RRM Glossary: A Detailed Reference to Restorative Reproductive Medicine

The Achieving-Related Pregnancy Rate (ARPR) is a use-effectiveness statistic developed within the Creighton Model FertilityCare System to measure pregnancy outcomes specifically among couples who have transitioned from avoiding conception to actively attempting it.⁸³ Unlike generic cumulative pregnancy rates, the ARPR isolates cycles in which fertility-focused intercourse was timed to the fertile window identified by Creighton Model charting. The denominator is controlled for intent and method use, which makes the resulting rate a more meaningful measure of fertility potential than unselected exposure statistics.

Open full entry →

Adenomyosis is a condition in which endometrial-like glands and stroma are present within the myometrium (uterine muscle wall), causing the uterus to enlarge and the junctional zone to thicken. The condition causes heavy periods, dysmenorrhea, dyspareunia, intermenstrual bleeding, and impaired fertility. It can also be asymptomatic and discovered incidentally.⁴⁸⁴⁹

Open full entry →

Adhesiolysis is the surgical division and removal of adhesions: bands of scar tissue that form between pelvic organs and surfaces following inflammation, prior surgery, or infection. Adhesions can distort pelvic anatomy, restrict organ mobility, occlude the fallopian tubes, and contribute to chronic pelvic pain and infertility. Adhesiolysis restores normal anatomical relationships by carefully separating and excising these fibrous attachments.

Open full entry →

Adhesion prevention refers to the set of surgical strategies employed before, during, and after pelvic surgery to minimize the formation of post-operative adhesions. Adhesions form when tissue surfaces that were separated by surgery heal in contact with each other. They can distort anatomy, impair tubal function, and contribute to chronic pelvic pain and infertility.

Open full entry →

Afollicularism is a sonographic ovulation disorder, developed and formalized by Dr. Thomas W. Hilgers within NaProTechnology, in which the cycle proceeds with regular menstrual bleeding but serial follicular ultrasound reveals the absence of meaningful follicular development across the entire periovulatory window.⁷⁸ No dominant follicle forms. No ovulation occurs.

Open full entry →

Anovulatory cycles are menstrual cycles in which the ovaries do not release an egg, though bleeding may still occur and be mistaken for a normal period. Anovulation is one of the most common causes of female infertility, accounting for roughly 30% of cases. The absence of ovulation means the corpus luteum never forms, progesterone is not produced, and the luteal phase does not occur.¹¹⁷

Open full entry →

Anti-adhesion barriers are materials placed during or at the close of pelvic surgery to physically separate tissue surfaces during the early healing period, reducing the formation of postoperative adhesions. When two traumatized peritoneal surfaces are in contact during healing, the resulting fibrin matrix can organize into permanent fibrous adhesions. Barrier materials interrupt this contact, giving each surface time to re-epithelialize independently.

Open full entry →

AMH is a glycoprotein produced by granulosa cells of small antral ovarian follicles. Its serum level reflects how many small follicles are currently active in the ovaries. That is a snapshot of this cycle's follicular activity, not a fixed inventory or a permanent verdict on reproductive potential.

Open full entry →

Antioxidant therapy is the use of compounds that neutralize reactive oxygen species (ROS) to reduce oxidative damage in the reproductive system. Oxidative stress occurs when ROS production exceeds the body's antioxidant defenses. In the reproductive system, excess ROS damages sperm DNA, impairs sperm motility, degrades oocyte quality, and disrupts the endometrial environment needed for implantation.³⁵⁵⁷

Open full entry →

Antiphospholipid Syndrome (APS) is an acquired autoimmune disorder in which the immune system produces antibodies against phospholipid-binding proteins, creating a hypercoagulable state that damages placental blood flow and causes thrombotic events. The three characteristic antibodies are lupus anticoagulant, anticardiolipin antibodies, and anti-beta-2 glycoprotein I antibodies.⁵²

Open full entry →

AFC (Antral Follicle Count) is a transvaginal ultrasound measurement taken in the early follicular phase that counts small, fluid-filled follicles visible in both ovaries, typically 2 to 10 mm in diameter. The total count from both ovaries is the AFC. It reflects the number of follicles beginning development at the start of that cycle and serves as a marker of ovarian reserve alongside AMH and FSH.⁷⁷¹⁰¹

Open full entry →

Assisted Reproductive Technology (ART) is the umbrella term for medical procedures in which eggs or embryos are handled outside the body to achieve pregnancy. The category includes in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), donor egg and donor sperm cycles, embryo banking, frozen embryo transfer, and gestational surrogacy. Note that intrauterine insemination (IUI), while sometimes grouped colloquially with fertility treatments, does not involve eggs handled outside the body and is classified separately from ART in CDC, HFEA, and SART reporting.⁹⁷

Open full entry →

Autoimmune and thrombophilic disorders are a category of conditions, acquired and inherited, that elevate clotting risk or disrupt immune tolerance in ways that impair implantation, placentation, and early pregnancy maintenance. They are among the identifiable, treatable causes of recurrent pregnancy loss that thorough evaluation can uncover. The category spans two overlapping groups: autoimmune conditions such as antiphospholipid syndrome and autoimmune thyroid disease, and inherited thrombophilias such as Factor V Leiden, the prothrombin G20210A mutation, and protein C or S deficiency.³⁷⁷⁵

Open full entry →

Azoospermia is the complete absence of sperm in the ejaculate, confirmed on at least two separate semen analyses after centrifugation.¹⁹³ It affects approximately 1% of men in the general population and up to 15% of men evaluated for infertility. The condition is classified into two mechanistically distinct categories: obstructive azoospermia (OAZ) and non-obstructive azoospermia (NOA).

Open full entry →

Basal Body Temperature (BBT) is the body's resting temperature, measured orally or vaginally first thing in the morning after at least three hours of uninterrupted sleep and before any activity, eating, or drinking. BBT rises 0.2 to 0.5 degrees C within one to three days after ovulation due to the thermogenic effect of progesterone released by the corpus luteum; this sustained shift produces a characteristic biphasic pattern on a cycle chart.⁹⁹ A thermal shift confirms that ovulation has occurred but cannot predict ovulation in advance. BBT is therefore useful for retrospective ovulation confirmation, luteal phase length measurement, and detection of anovulation, but is not reliable as the sole marker for identifying the fertile window. Accuracy depends on consistent timing, adequate sleep, and the absence of confounders (illness, alcohol, disturbed sleep, shift work). BBT is a core component of sympto-thermal methods and a secondary confirmatory marker in several other FABMs.

Open full entry →

The Base Infertile Pattern (BIP) is a woman's individual baseline of dryness or unchanging, featureless discharge that persists across consecutive days in the pre-Peak phase, during which conception is unlikely.⁷⁴

Open full entry →

The Billings Ovulation Method (BOM) is a mucus-only fertility awareness method developed by Australian physicians Drs. John and Evelyn Billings in the 1950s, based on the recognition that cervical mucus characteristics at the vulva change predictably across the cycle in response to estrogen and progesterone.⁷⁴ No thermometer, monitor, or instrument is required. BOM is taught through observation of sensation and appearance alone, making it one of the most globally accessible fertility awareness systems across varied cultural and resource settings.

Open full entry →

Biomarkers, in reproductive medicine, are observable biological signals that change predictably across the menstrual cycle and reflect underlying hormonal and physiologic events. Primary biomarkers include cervical mucus quality and sensation (rising estrogen), basal body temperature (rises after ovulation with progesterone release), urinary LH and estrogen metabolites (E1G), and serum hormone levels drawn at cycle-phase-specific intervals. Each marker maps to a distinct physiologic event rather than representing a single undifferentiated measure of fertility.⁸⁹

Open full entry →

Body literacy is an informed understanding of the body's biological signs and reproductive cycle, developed through systematic fertility charting and education. The concept of body literacy as a distinct framework emerged from women's health advocacy and is foundational to fertility awareness-based methods (FABMs).⁸⁸ Body literacy enables couples to recognize cycle abnormalities early, time intercourse and diagnostics appropriately, and engage actively in clinical care. For the male partner, it includes understanding how lifestyle factors affect sperm health and fertility timing. In RRM, body literacy converts raw cycle observations into clinical data that guides root-cause diagnosis and treatment.¹

Open full entry →

Body Mass Index (BMI) is a numerical index calculated by dividing weight in kilograms by height in meters squared (kg/m²), used as a population-level screening tool for weight-related health risk. The World Health Organization classifies BMI below 18.5 as underweight, 18.5 to 24.9 as normal range, 25.0 to 29.9 as overweight, and 30.0 or above as obese. BMI does not measure body composition or metabolic health directly, and its limitations are well documented at the individual level.^[69]

Open full entry →

CD138 (Syndecan-1) immunohistochemistry is a specialized staining technique applied to endometrial biopsy specimens to identify plasma cells, which are pathognomonic (definitively diagnostic) for chronic endometritis.²⁶ CD138 is a transmembrane proteoglycan specifically expressed on plasma cell membranes. Standard histologic staining (H&E) misses plasma cells at clinically significant rates; CD138 immunostaining substantially improves detection sensitivity, making it the current diagnostic standard when chronic endometritis is suspected.²⁶ Diagnostic thresholds vary by laboratory, but most published protocols flag one or more CD138-positive plasma cells per high-power field as abnormal. In the RRM workup, CD138 testing is considered particularly in couples with recurrent pregnancy loss or repeated implantation failure, where an undetected chronic endometritis may be a treatable contributing cause.

Open full entry →

Cervical factor infertility is the inability to conceive due to cervical mucus that is absent, insufficient in quantity, hostile in quality, or structurally compromised in a way that prevents sperm from reaching the upper reproductive tract. Cervical mucus serves as both a transport medium and a biological filter during the fertile window. When mucus is inadequate, sperm cannot survive the cervical environment long enough to reach the fallopian tubes. This makes cervical function an essential but frequently underassessed variable in fertility evaluation.⁷⁴

Open full entry →

ChartNeo is a digital cycle-charting platform developed by Dr. Phil Boyle as part of the NeoFertility restorative reproductive medicine framework.¹⁴⁶ It enables couples to record cycle observations, integrate hormonal monitoring data, and share charts with their clinician for cycle-timed evaluation and treatment.

Open full entry →

Chronic Endometritis (CE) is a persistent, low-grade inflammatory condition of the endometrial lining caused by abnormal bacterial colonization (e.g., Enterococcus, E. coli, Streptococcus). CE is often subclinical with no obvious symptoms. It significantly impairs endometrial receptivity and is strongly associated with recurrent implantation failure and recurrent pregnancy loss. Diagnosis requires office hysteroscopy (strawberry-pattern micropolypoid endometrium) confirmed by CD138 immunohistochemistry on endometrial biopsy. Treatment uses targeted antibiotics (typically doxycycline, amoxicillin, or based on culture). A cohort study found the biopsy and treatment group had significantly higher rates of pregnancy (HR 2.28) and live birth (HR 2.76) compared to hysteroscopy-only controls.⁵¹²⁶

Open full entry →

Chronic pelvic pain (CPP) is persistent or recurrent pain in the pelvis lasting six months or longer, unrelated to menstruation alone, that causes functional impairment or requires medical care. It is not a diagnosis. It is a symptom that demands one. CPP can arise from endometriosis, adenomyosis, pelvic adhesions, interstitial cystitis, irritable bowel syndrome, or pelvic floor dysfunction, and more than one cause often operates at the same time.^[208]

Open full entry →

Clinical Endorphin Deficiency (CED) is a clinical pattern, formalized within NaProTechnology by Dr. Thomas W. Hilgers, characterized by chronic pelvic pain, mood symptoms including depression and anxiety, and difficulty recovering from physical or emotional stress. The pattern reflects dysfunction in the endogenous opioid system: beta-endorphins and related opioid peptides modulate GnRH pulsatility at the hypothalamic level, with downstream effects on LH and FSH secretion and on ovarian function.⁷⁸ When endorphin tone is insufficient, that neuroendocrine signaling breaks down in ways that are clinically recognizable before they show up cleanly on standard hormone panels.

Open full entry →

Thrombophilia is an inherited or acquired condition that shifts the balance of the coagulation system toward clot formation, increasing the risk of pathological thrombosis. Inherited forms include Factor V Leiden, prothrombin G20210A mutation, antithrombin deficiency, protein C deficiency, protein S deficiency, and MTHFR variants associated with elevated homocysteine. The acquired form most relevant to reproductive medicine is antiphospholipid syndrome (APS), an autoimmune condition that generates antibodies against phospholipid-binding proteins.^[75]

Open full entry →

The compounding pharmacist collaboration in NaProTechnology is a structured clinical relationship connecting three roles: the NaProTechnology-trained physician, the FertilityCare practitioner, and a licensed compounding pharmacist who prepares individualized isomolecular hormone formulations. Dr. Thomas W. Hilgers formalized this clinical structure as part of NaProTechnology, not as an ancillary arrangement but as an integral component of the medical care model.⁷⁸

Open full entry →

In RRM, comprehensive evaluation is a systematic diagnostic workup of both partners, designed to find the root cause of reproductive dysfunction rather than assign a descriptive label. Tools include detailed cycle charting (using the Creighton Model or other FABMs), cycle-timed hormonal blood draws (taken at biologically meaningful days post-ovulation, not arbitrary cycle days), transvaginal ultrasound series (including saline infusion sonohysterogram -- a fluid-enhanced ultrasound to assess uterine cavity), hysterosalpingogram (HSG -- an X-ray procedure to evaluate tubal openness), semen analysis with DNA fragmentation index, and targeted testing for endocrine, immune, clotting, or genetic factors. Diagnostic laparoscopy and hysteroscopy (camera-based visualization of the pelvis and uterine interior) are employed when indicated for definitive diagnosis of endometriosis, pelvic adhesions, chronic endometritis, and isthmoceles.³

Open full entry →

Cooperative Estrogen Replacement Therapy (CERT) is a NaProTechnology protocol, developed by Dr. Thomas W. Hilgers, that targets estrogen deficiency across the reproductive cycle in specific clinical indications, including deficient cervical mucus production, selected subtypes of luteal phase deficiency, and other restorative care contexts where estrogen output is inadequate.⁷⁸

Open full entry →

Cooperative Progesterone Replacement Therapy (CPRT) is a NaProTechnology protocol, developed by Dr. Thomas W. Hilgers, that restores luteal phase progesterone production through cycle-timed supplementation in women with documented luteal phase deficiency or specific patterns of early pregnancy loss.⁷⁸

Open full entry →

The corpus luteum (CL) is a temporary endocrine structure that forms from the ruptured follicle after ovulation and produces the progesterone required to prepare the endometrium for implantation. It also secretes estradiol in moderate amounts. Without an adequately functioning corpus luteum, the endometrial environment cannot support implantation, and early pregnancy cannot be sustained.⁴⁴

Open full entry →

Corpus Luteum Deficiency (CLD) is a condition in which the corpus luteum produces insufficient progesterone to adequately support the endometrium for implantation and early pregnancy maintenance. CLD names the anatomical source of the deficit: the corpus luteum itself is underperforming. This distinguishes it from Luteal Phase Deficiency (LPD), which describes the hormonal pattern. CLD is the structural cause; LPD is the measurable consequence. A clinician can observe LPD on a progesterone profile without identifying CLD as the origin, and treat downstream without correcting upstream.

Open full entry →

RRM corrects the conditions causing reproductive dysfunction; it does not circumvent them, suppress them, or remove the affected organ.² Corrective approaches include surgical repair of the fallopian tubes, isthmocele reconstruction, adhesion excision, hormonal correction of luteal phase deficiency, antibiotic treatment of chronic endometritis, and varicocele repair for male-factor infertility. Each targets the cause. Bypass therapies circumvent the problem without treating it: IVF routes around a blocked tube, leaving the disease in place. Suppressive therapies quiet the symptom: hormonal contraception controls endometriosis pain while disease continues to progress. Hysterectomy removes the organ entirely. RRM treats none of these as acceptable defaults when a corrective path exists.¹

Open full entry →

Couple-based treatment is the clinical principle that both partners are evaluated and treated as a unit when infertility or recurrent pregnancy loss is the concern. Male factor is the sole cause of infertility in approximately 20% of couples and a contributing factor in another 30 to 40%.¹⁹³ Evaluating only the female partner means a significant portion of root causes go unaddressed from the first appointment.

Open full entry →

The Creighton Model FertilityCare System (CrMS) is a standardized, prospective method of natural family planning based on daily systematic observation and classification of cervical mucus at the vulva. Developed by Dr. Thomas Hilgers at the Pope Paul VI Institute, CrMS uses a precise notation system for mucus characteristics including color, consistency, and sensation. It is used by couples to achieve or avoid pregnancy and, in conjunction with NaProTECHNOLOGY, to identify cycle-phase abnormalities that guide targeted medical and surgical treatment. The CEIBA prospective cohort study, conducted across 17 CrMS centers in the USA and Canada, reported a 13-cycle pregnancy rate of 89.6% among couples using correct CrMS technique and timing intercourse to peak-type mucus days.⁸ CrMS is distinct from other fertility awareness-based methods: its developers classify it specifically as an NFP method, and its standardized notation forms the diagnostic data layer that NaProTECHNOLOGY relies on for cycle-timed blood tests and interventions. The Peak Day reference point established in CrMS charting is central to NaPro's hormone evaluation protocols.

Open full entry →

Cycle-Timed Diagnostics is the principle of ordering hormonal panels, ultrasound studies, and other diagnostic tests at cycle phases identified through fertility charting rather than on arbitrary calendar dates. The menstrual cycle is not hormonally uniform. Reproductive hormone levels vary substantially by cycle phase, and drawing blood outside the relevant phase can return values that appear normal while masking a real abnormality. Conversely, a value drawn in a phase-inappropriate window may flag as abnormal when it reflects normal cyclic variation. When clinicians know where a patient is in her cycle through FABM charting, they can order tests at the phases where each analyte carries diagnostic meaning. This principle transforms charting from a family planning tool into a clinical diagnostic instrument.³¹¹⁷ The luteal phase, the peak day event, and the follicle maturation study are examples of charting landmarks that anchor diagnostic timing. Named methods such as NaProTechnology and NeoFertility have formalized cycle-timed testing into structured diagnostic protocols; the specific phase-timing and test sequences each method uses are defined within those methods. Acyclic testing, in which blood is drawn without reference to cycle phase, remains the default in most conventional fertility workups. RRM clinicians consider this approach insufficient when cycle-phase-dependent hormones are under evaluation.

Open full entry →

Delayed Rupture Syndrome (DRS) is a sonographic ovulation disorder, developed and formalized by Dr. Thomas W. Hilgers within NaProTechnology, in which the dominant follicle collapses later than the timing of the woman's charted Peak Day observation would predict.⁷⁸ Rather than rupturing in close proximity to Peak Day, the follicle persists for a measurable interval beyond the expected window before eventually collapsing.

Open full entry →

DHEA (dehydroepiandrosterone) supplementation refers to the clinical use of this androgen precursor hormone to address low androgen levels in women with diminished ovarian reserve or related reproductive conditions. DHEA is produced primarily by the adrenal glands and serves as a precursor to both estrogen and testosterone. In the ovarian microenvironment, adequate androgen signaling supports follicular development and granulosa cell function. When androgen levels are low, follicular maturation may be impaired, and some clinicians consider DHEA supplementation as part of a broader restorative evaluation.¹⁴⁷

Open full entry →

Diminished Ovarian Reserve (DOR) is a reduction in the quantity and, often, the quality of the remaining egg supply in the ovaries relative to what is expected for a woman's age. DOR is most commonly age-related, but it can occur prematurely due to prior ovarian surgery, autoimmune conditions, endometrioma, genetic factors, or prior gonadotoxic treatment. It does not make pregnancy impossible. It makes it more urgent to act, and more important to understand why reserve is low.¹²⁰

Open full entry →

DPO, or days post ovulation, is a day-counting convention that numbers days relative to the estimated day of ovulation, with ovulation assigned as 0 DPO, the following day as 1 DPO, and so on through the remainder of the cycle. The convention is widely used in fertility-tracking apps and trying-to-conceive communities as a shorthand for locating cycle events relative to the fertile window, though the calendar-estimated ovulation date it relies on varies substantially between women and between cycles, whereas the fertile window itself is defined biologically by hormonal markers, with conception concentrated in the few days around ovulation.²⁴⁵²⁴⁶

Open full entry →

A dry day is a charted cycle day on which no cervical mucus is observed at the vulva, no bleeding is present, and no sensation of wetness or lubrication is noted. Dry days are a normal and expected feature of healthy cycles, appearing both before mucus begins to develop and after the peak symptom has passed. They are not days of abnormality. They are days of relative quiescence, each with a distinct hormonal explanation depending on where they fall.⁷⁴

Open full entry →

Early pregnancy loss (EPL) is the spontaneous loss of a clinically confirmed pregnancy before 13 weeks of gestation. It is the most common complication of pregnancy, affecting approximately 10 to 20% of confirmed pregnancies. The majority of isolated losses result from chromosomal aneuploidy in the embryo, and a single loss in an otherwise healthy couple carries a reasonable prognosis for subsequent success without intervention.¹²⁹

Open full entry →

EMMA and ALICE are molecular diagnostic tests that analyze the endometrial microbiome from a biopsy sample. EMMA (Endometrial Microbiome Metagenomic Analysis) measures the composition of bacteria present in the endometrium, including the proportion of Lactobacillus species, which research associates with better implantation outcomes, and the presence of dysbiotic organisms. ALICE (Analysis of Infectious Chronic Endometritis) identifies specific pathogenic bacteria associated with chronic endometritis, a condition linked to recurrent implantation failure and recurrent pregnancy loss.⁶⁵

Open full entry →

Empty Follicle Syndrome (EFS) is an ovulation disorder in which the dominant follicle reaches mature size and ruptures appropriately, yet no oocyte is recovered at the expected reproductive event.⁷⁸ Serial ultrasound demonstrates apparent follicular growth and collapse, but the cycle’s reproductive outcome fails at the oocyte level.

Open full entry →

Endometrial hyperplasia is an overgrowth of the uterine lining caused by prolonged estrogen exposure without adequate progesterone to oppose it. The glands proliferate and crowd, producing abnormal uterine bleeding as the most common presenting symptom. Atypical hyperplasia (also called endometrial intraepithelial neoplasia) carries a significant risk of progression to endometrial adenocarcinoma if left untreated; a long-term cohort study estimated cancer progression in roughly one quarter of cases.²⁰⁶ Non-atypical hyperplasia carries substantially lower cancer risk and often resolves with hormonal correction.

Open full entry →

ERA (Endometrial Receptivity Analysis) is a molecular diagnostic test that analyzes gene expression in an endometrial biopsy sample to estimate the personalized timing of the window of implantation (WOI): the period during which the endometrium is receptive to embryo implantation. The test analyzes the expression profile of several hundred genes. Based on results, the laboratory classifies the sample as receptive, pre-receptive, or post-receptive and recommends adjusted embryo transfer timing.²³²⁴

Open full entry →

Endometrial thickness is the measurement of the uterine lining obtained by transvaginal ultrasound, assessed at defined points in the menstrual cycle to evaluate implantation potential. A trilaminar (three-layer) pattern in the preovulatory phase indicates coordinated estrogen stimulation of the endometrium. Thickness below an adequate preovulatory range is associated with reduced implantation potential, though exact thresholds vary by population and cycle type.⁸⁷

Open full entry →

An endometrioma is an ovarian cyst formed when endometriotic tissue implants on or within the ovary and fills with old menstrual blood, producing the characteristic dark-brown "chocolate cyst" appearance. Endometriomas are not benign bystanders. They destroy healthy follicular tissue, reduce ovarian reserve, and impair oocyte quality by creating an inflammatory, iron-rich environment within the ovary itself.¹¹⁵

Open full entry →

Endometriosis is a chronic inflammatory condition in which tissue similar to the endometrium grows outside the uterine cavity, most commonly on the ovaries, fallopian tubes, pelvic peritoneum, and uterosacral ligaments. It affects approximately 1 in 10 women of reproductive age, and up to 50% of women presenting with infertility.²⁸ Despite this prevalence, the median time from symptom onset to diagnosis is 9 years,⁹⁸ a delay driven by normalized dismissal of pelvic pain and dysmenorrhea as routine. Endometriosis causes inflammation, adhesion formation, distorted pelvic anatomy, and impaired tubal and implantation function, all of which affect both the woman's health and a couple's fertility. RRM's standard surgical treatment is laparoscopic excision surgery, which demonstrates significantly greater improvement across symptom domains compared to ablation.²⁸ Hormonal suppression after surgery masks disease activity without treating the underlying condition: it does not stop disease progression. For complex pelvic disease, clinicians may employ PEARS, NARPS, or S-MAP techniques alongside adhesion prevention.

Open full entry →

The Essential Sameness Pattern (ESP) and Yellow Stamps are the CrMS construct for charting infertility windows when continuous discharge is present: the ESP defines pre-Peak infertile days through day-to-day identical observations, and Yellow Stamps are the chart symbol that records those days.⁷⁸

Open full entry →

Excision surgery is the complete surgical removal of endometriotic tissue by cutting it out at the margins, including lesion depth, rather than only destroying the surface. The operating surgeon resects each lesion from surrounding tissue under direct visualization, removing the disease in full. This stands in contrast to ablation and fulguration, which destroy only the visible surface while leaving deeper implants intact.

Open full entry →

The fallopian tube is a paired muscular and ciliated structure, roughly 10 to 12 centimeters in length, connecting each ovary to the uterine cavity and serving as the site of fertilization and early embryo transport.⁴⁶⁴⁷ Its function depends on intact mucosal cilia, coordinated muscular contractions, and normal secretory activity across all four anatomic segments.

Open full entry →

Fallopian tube recanalization (tubal cannulation) is a minimally invasive procedure that restores patency to a proximally blocked fallopian tube by passing a small catheter transcervically through the uterine cavity and into the tube under fluoroscopic or hysteroscopic guidance. Proximal tubal occlusion, located near the uterotubal junction, is distinct from distal disease and is frequently caused by mucus plugging, amorphous debris, or inflammatory fibrosis. A significant proportion of apparent proximal occlusions identified on HSG are not true anatomical blocks; recanalization resolves these in many cases in a single outpatient procedure without surgery.

Open full entry →

FEMM (Fertility Education and Medical Management) is a physician-integrated fertility awareness program that pairs cycle charting with hormonal science education and a structured framework for medical management based on cycle data. FEMM was developed through the Reproductive Health Research Institute and is taught through a tiered curriculum for both patients and clinicians.¹³³

Open full entry →

FEMM Education Levels are the three tiered learning pathways offered by the FEMM (Fertility Education and Medical Management) program, matched to the user's life stage and clinical need: Teen FEMM, Adult FEMM, and FEMM Medical Management. Each tier builds on the same underlying framework of restorative endocrinology and cycle-based health literacy, at different depths and with different applications.¹³³

Open full entry →

FEMM Medical Management is the clinical treatment tier of the FEMM (Fertility Education and Medical Management) program, in which trained FEMM Medical Providers use cycle charting data and cycle-timed laboratory evaluation to identify and treat hormonal and reproductive disorders. It is developed and supported by the Reproductive Health Research Institute (RHRI) and represents the physician-level application of FEMM's restorative endocrinology framework.¹³³

Open full entry →

The Fertilitas Study is a 5-year retrospective cohort study of 1,310 infertile couples treated with NaProTECHNOLOGY at a specialized reproductive medicine clinic in Spain, published in 2025 in Frontiers in Reproductive Health. It is one of the largest single-center NaProTECHNOLOGY outcome datasets published to date and provides real-world effectiveness data across a population with multiple unfavorable prognostic factors.¹⁴⁹³

Open full entry →

Fertility Awareness-Based Methods (FABMs) are scientific methods used to monitor and interpret biological signs of fertility (biomarkers) throughout the menstrual cycle. FABMs can be used for health monitoring, timing diagnostics and treatments in RRM, and achieving or avoiding pregnancy. A 2025 systematic review of 20,339 participants from 16 studies found FABMs, when used correctly, were associated with a success rate of over 90% for both contraceptive and conception purposes.⁶ FABMs encourage partner involvement, improve communication, and enhance body literacy by tracking biomarkers to determine fertility status. They also aid in identifying ovulation-related disorders such as PCOS and endometriosis. Specific methods include the Creighton Model FertilityCare System, the Billings Ovulation Method, the Sympto-Thermal Method, and the Marquette Method. Note: The Creighton Model FertilityCare System is specifically classified as an NFP method by its developers and is distinct from the FABM umbrella.⁵

Open full entry →

Fertility Charting is the systematic daily recording of fertility biomarkers according to a specific standardized method, such as the Creighton Model or another FABM. Biomarkers recorded typically include cervical mucus quality and quantity, cycle bleeding patterns, and supplementary signs such as basal body temperature or urinary hormone levels. Chart data function analogously to an ECG for the reproductive system, revealing hormonal patterns, potential abnormalities, and optimal windows for diagnostics, treatment timing, and intercourse. Tracking these observations across multiple cycles is essential: patterns invisible in a single cycle become diagnostically clear over time. Changes in charting patterns serve as a form of biofeedback to assess treatment efficacy.¹¹⁰⁰

Open full entry →

Fertility-focused intercourse (FFI) is the practice of a couple timing relations to align with the fertile window identified through FABM charting, particularly the days around and preceding the Peak Day.⁸³

Open full entry →

FertilityCare Practice is the named-method clinical discipline that integrates Creighton Model FertilityCare System charting instruction with NaProTechnology medical evaluation. A FertilityCare Practitioner (FCP) is a credentialed educator who teaches CrMS charting to clients, follows their charts longitudinally, and communicates findings to the NaProTechnology Medical Consultant who directs medical care. The FCP role is the instructional backbone of the NaProTechnology model: the clinical data that drives diagnosis flows through CrMS charting, and accurate charting requires consistent FCP support.⁷⁶⁴ FertilityCare Practitioners are credentialed through the American Academy of FertilityCare Professionals (AAFCP). The FertilityCare practice model is distinct from the NaProTechnology Medical Consultant role: the FCP instructs and monitors charting; the physician evaluates and treats. Other RRM methods have parallel educator structures: FEMM Teachers, Marquette instructors, and sympto-thermal educators serve comparable instructional functions within their respective clinical systems. Fertility charting is the shared foundation across all of these models.

Open full entry →

A FertilityCare Practitioner (FCP) is a credentialed educator trained to teach the Creighton Model FertilityCare System to individuals and couples. FCPs are not physicians. Their role is to teach accurate observation of biological cycle markers, support clients in building a standardized chart record, and identify patterns that warrant referral to a medical consultant. The credential is issued through the FertilityCare Centers of America training program.⁷

Open full entry →

Follicle development is the process by which a cohort of ovarian follicles is recruited each cycle, one dominant follicle is selected and matures to ovulatory size, and the remaining follicles regress through atresia. Under rising FSH stimulation during the follicular phase, a group of antral follicles begins to grow. By cycle days 5 to 7, one follicle achieves dominance through greater FSH receptor density and local estrogen production. That dominant follicle expands to approximately 18 to 24 mm, produces rising estradiol, and triggers the midcycle LH surge. The LH surge initiates the cascade that ends in follicle rupture, oocyte release, and corpus luteum formation.

Open full entry →

A Follicle Maturation Study (FMS) is a series of transvaginal ultrasounds performed across the follicular phase of the menstrual cycle to track follicular growth, the ovulation event, and post-rupture changes in real time. A single scan cannot reveal how ovulation actually unfolds. The series does. By imaging the follicle from growth through collapse and corpus luteum formation, clinicians can distinguish normal ovulatory release from several distinct disorders that a single hormone level or standard cycle assessment would miss.

Open full entry →

Follicle stimulation refers to the use of pharmacological agents to recruit follicle development and support ovulation in cycles where the natural process is absent or inadequate. Two principal agent classes are used: oral agents, including clomiphene citrate (a selective estrogen receptor modulator) and letrozole (an aromatase inhibitor); and injectable gonadotropins, preparations containing FSH alone or FSH combined with LH. The appropriate agent class depends on the underlying ovulatory disorder, the clinical method being applied, and how the patient's cycle is being monitored. A 2014 randomized trial in the New England Journal of Medicine found letrozole superior to clomiphene for live birth rates in women with PCOS-related anovulation.⁷⁶

Open full entry →

Follicle-Stimulating Hormone (FSH) is a glycoprotein gonadotropin secreted by the anterior pituitary gland in response to hypothalamic GnRH pulses, with the primary function of stimulating ovarian follicle recruitment and maturation during the follicular phase of the cycle. Each cycle, FSH recruits a cohort of follicles. One typically becomes dominant and proceeds to ovulation. That process depends on an FSH rise that begins in the late luteal phase of the prior cycle, well before menstruation starts.

Open full entry →

Follicular Deficiency is a clinical RRM concept describing an ovulatory pattern in which the dominant follicle reaches adequate size and ruptures on schedule but does not produce sufficient hormonal output to support fertilization and implantation. The defect is functional, not anatomic. The follicle looks normal on ultrasound. It ruptures. The problem is invisible to imaging and only becomes legible through the hormonal record the cycle leaves behind.⁷⁸ This distinguishes it from the four named ovulation disorders in Hilgers' Sonographic Ovulation Classification: luteinized unruptured follicle, immature follicle syndrome, afollicularism, and empty follicle syndrome.

Open full entry →

Fulguration, ablation, and cauterization are techniques that destroy endometriotic tissue at the surface using electrical energy, laser, or heat, without removing the underlying lesion. The tissue is burned or vaporized in place. Because the destruction is superficial, lesion depth is not addressed and the tissue is not extracted for pathologic confirmation.

Open full entry →

Functional and nutritional medicine is a whole-person approach to health that addresses micronutrient status, metabolic function, gut health, blood-sugar regulation, sleep, stress, and weight as root contributors to reproductive outcomes. Rather than treating fertility as a single-organ question, this approach recognizes that ovulation, implantation, and early pregnancy maintenance depend on systemic metabolic conditions. Deficiencies in folate, vitamin D, zinc, iron, omega-3 fatty acids, and B vitamins, as well as elevated inflammatory markers and uncontrolled insulin resistance, can each disrupt the hormonal signaling that governs the reproductive cycle.³

Open full entry →

An hCG trigger is an injectable dose of human chorionic gonadotropin given during a monitored cycle to induce final follicular maturation and ovulation by mimicking the body's natural LH surge. The trigger works because hCG is structurally similar to LH and binds the same receptor, producing the hormonal signal needed for the dominant follicle to complete maturation and rupture.¹²² Timing of the injection is guided by follicle development monitoring, typically via ultrasound assessment of follicular size alongside cycle observation data.

Open full entry →

Heteromolecular artimones (HMA) are hormone-like compounds whose molecular structure differs from the hormones the human body produces naturally. The term was coined by Dr. Thomas W. Hilgers as part of NaProTechnology, specifically to contrast with isomolecular hormones, which replicate endogenous molecular structure. Examples include norethindrone, medroxyprogesterone acetate, conjugated equine estrogens, and ethinyl estradiol: the active agents found in most oral contraceptives and many conventional hormone replacement formulations.⁷¹

Open full entry →

The RRM principle that reproductive dysfunction rarely involves one organ system in isolation. In clinical practice, this means evaluating the endocrine, immune, metabolic, and inflammatory systems alongside pelvic anatomy, in both partners, to understand what is driving the presenting problem.¹ Thyroid dysfunction alters cycle length and luteal function. Insulin resistance drives anovulation in PCOS. Chronic inflammation affects implantation. These connections are not incidental. RRM treats them as primary diagnostic targets. The same framework applies to male reproductive health: systemic conditions such as metabolic syndrome and hormonal imbalance directly impair sperm production and function. This approach is grounded in internal medicine diagnostics and differs from "holistic" wellness language. The evaluation is clinical, systematic, and evidence-based.

Open full entry →

Hormonal abnormalities are disruptions in the reproductive endocrine system that impair follicle development, ovulation, luteal function, or early pregnancy support. The hormones most frequently evaluated in reproductive medicine include FSH, LH, estradiol, progesterone, prolactin, TSH, and AMH. Each operates within a tightly regulated feedback network. A disorder in one axis typically propagates through others, which is why isolated single-hormone testing outside cycle context misses the clinical picture.⁸⁹

Open full entry →

Hormone replacement therapy (HRT) is the exogenous administration of estrogen, progesterone, or both, to address the decline in hormonal production that occurs during perimenopause, menopause, or in conditions such as premature ovarian insufficiency (POI). HRT reduces vasomotor symptoms (hot flashes, night sweats), slows bone loss, and may lower cardiovascular risk when initiated in the early postmenopausal window. Documented risks include venous thromboembolism and, with combined estrogen-progestogen therapy, a modest increase in breast cancer risk that varies by formulation, duration, and timing of initiation.⁷³

Open full entry →

Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast immediately after implantation, and it is the hormone detected by all standard pregnancy tests. Its first biological role is to rescue the corpus luteum from regression, sustaining progesterone production until the luteo-placental shift at approximately 8 to 10 weeks of gestation. Without this rescue signal, the corpus luteum involutes and progesterone falls, ending the pregnancy before the placenta is ready to take over steroid production.

Open full entry →

Hydrosalpinx is a distally occluded, fluid-filled fallopian tube resulting from prior infection, endometriosis, or adhesive disease that seals the fimbrial end.⁴⁷ The accumulated serosal fluid is not inert: it is biochemically hostile to embryo implantation, and its retrograde flow into the uterine cavity disrupts the endometrial environment.

Open full entry →

Hyperprolactinemia is an elevated serum prolactin level that suppresses pulsatile GnRH secretion, reducing LH and FSH and disrupting ovulation. The result is anovulatory cycles, shortened or absent luteal phases, and impaired fertility. Galactorrhea (spontaneous nipple discharge) may accompany elevated prolactin but is not always present.¹¹⁹

Open full entry →

Hypothyroidism is a condition of insufficient thyroid hormone production, most commonly caused by autoimmune Hashimoto's thyroiditis in iodine-sufficient regions. It is diagnosed by elevated TSH with low or normal free T4. Subclinical hypothyroidism is a milder form: TSH is elevated while free T4 remains within normal range. Both conditions affect reproductive function. Subclinical hypothyroidism is associated with ovulatory dysfunction, impaired implantation, and increased miscarriage risk even when symptoms are absent.¹¹³

Open full entry →

A hysterosalpingogram (HSG) is a radiographic procedure in which radiopaque contrast dye is injected through the cervix into the uterine cavity and fallopian tubes under fluoroscopic X-ray guidance.¹⁷ HSG provides a real-time image of uterine cavity shape and tubal patency. It detects structural uterine abnormalities including polyps, fibroids, intrauterine adhesions, and septal defects, as well as proximal or distal tubal obstruction. HSG has limitations: false-positive tubal occlusion results from tubal spasm occur, and peritoneal endometriosis or pelvic adhesions are not visible on HSG. In the RRM infertility evaluation, HSG is often an early step in the tubal assessment workup. It may be followed by diagnostic laparoscopy for definitive assessment of pelvic pathology. When proximal tubal obstruction is identified on HSG, clinicians may proceed to selective salpingography or transcervical catheterization of the fallopian tubes, a therapeutic extension of the diagnostic study that is a distinctive RRM/NaPro surgical technique.

Open full entry →

Diagnostic hysteroscopy is the direct endoscopic visualization of the uterine cavity and cervical canal using a thin, illuminated camera introduced through the cervix, without incision. It provides a real-time view of the endometrium and uterine walls that no imaging test fully replicates. Major professional society guidelines recognize diagnostic hysteroscopy as the definitive standard for evaluation of intrauterine pathology.¹⁷¹⁸

Open full entry →

Operative hysteroscopy is the therapeutic use of a hysteroscope to treat intrauterine pathology identified during visualization, using specialized instruments passed through the operative channel of the scope. It extends the diagnostic procedure directly into treatment: the same cavity view used for diagnosis becomes the operative field, without abdominal incision or the need for a separate surgical admission in most cases.¹⁷¹⁸

Open full entry →

Immature Follicle Syndrome (IFS) is an ovulation disorder in which the dominant follicle ruptures before reaching the size associated with follicular maturity, preventing reliable release of a fully developed oocyte.⁷⁸ A follicle that collapses prematurely cannot support normal oocyte development or adequate corpus luteum formation.

Open full entry →

The Immune-Modifying Framework is a clinical orientation adopted in some restorative reproductive medicine practices for couples experiencing recurrent pregnancy loss or unexplained implantation failure, in which immune system contributors are evaluated and addressed as part of the diagnostic workup. The framework is most explicitly developed within NeoFertility's clinical approach under Dr. Phil Boyle, though related immunological evaluation appears across multiple named-method practices. The core premise is that dysregulated immune activity at the implantation interface can be a diagnosable contributor to pregnancy failure, rather than an idiopathic outcome.³⁷²⁰⁹

Open full entry →

Infertility is the failure to achieve a clinical pregnancy after 12 months of regular unprotected intercourse, or after 6 months for women aged 35 and older. The World Health Organization estimates infertility affects approximately 17.5% of adults globally, or roughly 1 in 6 people.¹¹² Primary infertility refers to couples who have never achieved pregnancy. Secondary infertility refers to those who have previously conceived but cannot again. See Secondary Infertility for the distinct clinical picture that condition presents.

Open full entry →

Insulin resistance is a state in which cells fail to respond normally to insulin, requiring progressively higher circulating insulin levels to achieve normal glucose uptake. In reproductive medicine, insulin resistance is most clinically significant in PCOS, where it is present in an estimated 50 to 70% of affected individuals regardless of body weight.³⁹ The mechanism linking insulin resistance to ovulatory dysfunction is direct: hyperinsulinemia stimulates ovarian theca cells to overproduce androgens, which disrupts follicle maturation and suppresses ovulation.

Open full entry →

Intracytoplasmic sperm injection (ICSI) is a laboratory procedure in which a single sperm is selected, immobilized, and injected directly into a mature egg using a fine glass needle. It was developed in the early 1990s as a solution for severe male factor infertility where conventional IVF fertilization rates were poor. ICSI bypasses the natural process of sperm-egg recognition and zona pellucida penetration entirely.

Open full entry →

Intratubal pressure (ITP) is a quantitative measure of fallopian tube patency obtained by recording the pressure required to advance contrast through the tube during selective hysterosalpingography, converting the standard binary open-or-closed assessment into graded resistance data.

Open full entry →

Intrauterine adhesions (Asherman's syndrome) are bands of scar tissue that form inside the uterine cavity, binding the walls together and disrupting the endometrial lining. They develop after uterine trauma: most commonly a dilation and curettage (D&C), uterine surgery, or severe intrauterine infection. Severity ranges from thin, filmy adhesions across a small segment of the cavity to dense fibrotic obliteration of most or all of it.¹⁷¹⁸

Open full entry →

An intrauterine device (IUD) is a small, T-shaped contraceptive device placed inside the uterine cavity. Two primary types exist: copper and hormonal. The copper IUD works without hormones. Copper ions impair sperm motility and inhibit fertilization. At higher concentrations, copper may also alter the endometrial environment in ways that affect implantation, though the primary mechanism operates before fertilization.

Open full entry →

Isomolecular hormones (IMH) are hormone preparations that are chemically identical to those the human body produces, including progesterone identical in molecular structure to that secreted by the corpus luteum and estradiol identical to that produced by the ovaries. The term was developed by Dr. Thomas W. Hilgers as part of NaProTechnology to distinguish these preparations from heteromolecular alternatives, hormone compounds that differ in molecular structure from endogenous hormones.⁸²

Open full entry →

Hysteroscopic isthmocele repair is a minimally invasive surgical procedure that addresses a cesarean scar defect (isthmocele or niche) by resecting the thin residual myometrial layer at the defect's inferior edge from inside the uterine cavity, reducing the niche depth and improving drainage of retained menstrual blood. Surgeons perform the procedure with a resectoscope or operative hysteroscope, without abdominal incisions. It represents the less invasive of the two primary surgical approaches to isthmocele correction.¹⁵¹⁷

Open full entry →

Laparoscopic isthmocele repair is surgical correction of a cesarean scar defect via laparoscopic access, involving excision of the fibrotic niche tissue and multilayer reconstruction of the uterine muscular wall at the lower uterine segment. Unlike the hysteroscopic approach, laparoscopic repair directly restores wall thickness and structural integrity by closing the defect in anatomical layers. This distinguishes it as the preferred technique when fertility preservation is the clinical goal or when residual myometrial thickness is below safe thresholds for hysteroscopic resection.¹⁵¹⁶

Open full entry →

Intrauterine insemination (IUI) is a procedure in which washed and concentrated sperm are deposited directly into the uterine cavity via a thin catheter, timed to coincide with ovulation. Fertilization, if it occurs, takes place in the fallopian tube. IUI bypasses the cervical environment but does not involve handling eggs outside the body. It is less technically demanding than IVF and does not require egg retrieval or laboratory fertilization. Indications include donor sperm use, mild male factor infertility, cervical factor infertility, and some cases of undiagnosed subfertility. Per-cycle pregnancy rates vary substantially by age, sperm parameters, and underlying cause.

Open full entry →

In vitro fertilization (IVF) is a form of assisted reproductive technology in which oocytes are retrieved from the ovaries following controlled ovarian hyperstimulation, fertilized with sperm in a laboratory culture dish, and the resulting embryo or embryos transferred to the uterus. RRM does not perform IVF. The distinction is not merely procedural. IVF bypasses the reproductive system rather than restoring it: the underlying anatomical, hormonal, and immunologic conditions that prevented conception remain uncorrected after the procedure. RRM's position is that those underlying conditions, in most couples, are diagnosable and treatable. Controlled hyperstimulation routinely produces more embryos than will be transferred in a single cycle. Embryos not transferred may be frozen, donated, used for research, or discarded. Each of those outcomes is a consequential decision, not a logistical one. Known risks include ovarian hyperstimulation syndrome (OHSS),⁹⁵ elevated rates of preterm birth and low birthweight compared to spontaneous conception,⁹⁶ and multiple pregnancy when more than one embryo is transferred. Per-cycle live-birth rates decline substantially with advancing maternal age; HFEA registry data show IVF live-birth rates of approximately 22% per embryo transferred for women aged 35-37, falling further at older ages.⁹⁷ The question RRM asks is different: not how to work around a failing reproductive system, but what is causing it to fail, and whether that cause can be corrected. See IVF vs. RRM: Key Conceptual Distinctions and NaProTECHNOLOGY for the restorative alternative.

Open full entry →

IVF vs. RRM is a conceptual comparison framework that contrasts two fundamentally different paradigms for treating infertility: assisted reproductive technology, which bypasses the reproductive system, and restorative reproductive medicine, which identifies and treats the underlying causes preventing natural conception. The distinction is not a matter of degree. It is a difference in the question being asked. IVF asks: how do we produce a pregnancy despite the barrier? RRM asks: what is the barrier and can it be resolved?

Open full entry →

Laparoscopic Ovarian Wedge Resection (LOWR) is a surgical procedure in which a wedge-shaped section of androgen-producing ovarian cortex is removed laparoscopically to normalize hormonal balance and restore ovulation in select patients with PCOS. The procedure reduces ovarian androgen production, which in PCOS drives the cycle of elevated LH, follicular arrest, and anovulation. LOWR has been performed using microsurgical technique with the goal of restoring spontaneous ovulation while avoiding the ovarian hyperstimulation risk associated with pharmacologic ovulation induction. In NaProTECHNOLOGY practice, LOWR is considered a surgical option for patients whose ovulation fails to respond to medical management. Clinicians performing LOWR use careful hemostasis and adhesion prevention to preserve ovarian reserve and reduce post-surgical scarring risk.

Open full entry →

Diagnostic laparoscopy is a minimally invasive surgical procedure that directly visualizes the peritoneal cavity, pelvic organs, and abdominal structures through small incisions using a camera-equipped scope. It is the gold-standard method for diagnosing endometriosis and pelvic adhesions, conditions that imaging alone frequently fails to detect. Definitive diagnosis of endometriosis requires direct visualization and histological confirmation by biopsy.⁹⁸

Open full entry →

Operative laparoscopy is a minimally invasive surgical approach that treats pelvic and abdominal pathology identified during laparoscopic visualization, addressing structural causes of pain, infertility, or pregnancy loss in the same or a planned subsequent procedure. Conditions commonly treated include endometriosis (via excision), ovarian endometrioma (via cystectomy), and pelvic adhesions (via adhesiolysis). Additional indications include uterine fibroids, tubal disease, isthmocele, and laparoscopic ovarian wedge resection in selected PCOS cases.

Open full entry →

A limited mucus cycle is a CrMS chart pattern in which observable cervical mucus is significantly reduced in quality, quantity, or duration during the pre-ovulatory phase, reflecting suboptimal estrogen stimulation of the cervical crypts.⁷⁸ It represents one classification on the Mucus Cycle Score spectrum and signals that follicular estrogen output during that cycle was below the threshold associated with normal mucus production.

Open full entry →

Low-dose naltrexone (LDN) is naltrexone (an opioid antagonist) used at sub-therapeutic doses, far below the 50 mg dose prescribed for opioid or alcohol dependence. At low doses, transient opioid receptor blockade triggers a compensatory increase in the body's own endorphin production and modulates T-regulatory cell activity, reducing pro-inflammatory cytokines such as TNF-alpha and IL-6.⁹⁰ This immune-modulating effect has been studied in chronic inflammatory conditions including multiple sclerosis and fibromyalgia.⁹¹⁹⁰ In RRM, LDN is considered by some clinicians as an adjunct in patients with suspected immune-mediated implantation failure, clinical endorphin deficiency, or endometriosis-associated immune dysregulation. Its use for these indications is off-label. Clinicians considering LDN should evaluate the individual patient's immune profile and reproductive history. No specific dosing protocol is published here; consult an RRM clinician.

Open full entry →

The Luteal Phase (LP) is the second half of the menstrual cycle, beginning at ovulation and ending at the onset of menstruation or, if conception occurs, continuing under the hormonal rescue of early pregnancy. It is defined clinically by the transformation of the ruptured follicle into the corpus luteum, which secretes progesterone and estradiol to prepare the endometrium for implantation. In a healthy cycle, the luteal phase typically spans 12 to 16 days.⁴⁴

Open full entry →

Luteal Phase Deficiency (LPD) is a hormonal condition in which the corpus luteum produces insufficient progesterone, the luteal phase is too short, or the endometrium fails to respond adequately to progesterone, impairing implantation and early pregnancy support. The most common causes are impaired follicular development leading to an under-capable corpus luteum, hypothyroidism, hyperprolactinemia, and disrupted GnRH pulsatility. The NaPro post-Peak duration threshold for a short luteal phase is 8 days, not the older 11-day BBT-phase criterion from the Vollman/Jones era. These measured different endpoints with different methods.⁴⁴⁴⁵

Open full entry →

Luteinized Unruptured Follicle (LUF) syndrome is a condition in which the dominant follicle undergoes luteinization, signaling progesterone production, without physically rupturing to release the oocyte. Ovulation appears to have occurred by hormonal parameters, and menstrual cycles typically proceed at normal intervals, yet fertilization cannot take place because the egg was never released. LUF syndrome is a clinically underappreciated contributor to infertility that goes undetected without serial ultrasound monitoring across the cycle.³

Open full entry →

Luteinizing Hormone (LH) is a glycoprotein gonadotropin secreted by the anterior pituitary in a pulsatile pattern, responsible for two essential events: the mid-cycle LH surge that triggers the ovulatory cascade, and ongoing stimulation of the corpus luteum to produce progesterone after ovulation.

Open full entry →

Male factor infertility refers to any condition arising from the male partner that reduces a couple's ability to conceive, including abnormalities of sperm count, motility, morphology, sperm DNA integrity, hormone levels, or reproductive anatomy. Male factor is the sole cause in approximately 20% of infertile couples and contributes alongside female factors in a further 20 to 45%.¹²⁵ Evaluating the male partner is not optional in RRM; it is a prerequisite.

Open full entry →

The Marquette Method is a fertility awareness approach developed at Marquette University's Institute for Natural Family Planning that uses the Clearblue fertility monitor to measure urinary metabolites of estrogen and luteinizing hormone (LH), providing objective low, high, and peak fertility readings in addition to optional cervical mucus observation.¹³⁴ The monitor's hormonal readings reduce the interpretive variability that can occur with mucus-only or temperature-only methods, particularly for women with atypical cycle patterns.

Open full entry →

The Marquette Method Clinical Protocol is a structured approach to fertility charting developed at the Marquette University Institute for Natural Family Planning, principally by Dr. Richard Fehring and colleagues beginning in the late 1990s. The protocol centers on the Clearblue Easy Fertility Monitor, a device that reads urinary levels of estrone-3-glucuronide (E1G) and luteinizing hormone (LH) to identify the fertile window objectively. Optional cervical mucus observation is layered alongside the monitor readings, making it one of the earliest named sympto-hormonal methods in the fertility-awareness literature.¹³⁴²³¹

Open full entry →

Mature reproductive age is a clinical designation for women aged 35 and older who are attempting pregnancy, acknowledging that fertility potential, egg quality, and time-to-pregnancy change meaningfully as the ovarian reserve that was built across childhood declines with accelerating pace through the mid-thirties and beyond. The designation does not imply a fertility cliff. It signals that a couple presenting at this stage benefits from greater clinical urgency and diagnostic depth.

Open full entry →

Menopause is the permanent cessation of menstruation, defined by 12 consecutive months of amenorrhea without an alternative clinical cause. In industrialized populations, the mean age at menopause is approximately 51 to 52 years, with a typical physiologic range of 45 to 55 years.²¹⁸ The biological basis is depletion of ovarian follicles: estradiol production falls to persistently low levels, and FSH rises in sustained elevation as the pituitary attempts to drive an ovarian response that no longer comes.

Open full entry →

Methylated folate (L-methylfolate, or 5-methyltetrahydrofolate) is the biologically active form of folate that cells use directly, without enzymatic conversion. Most prenatal vitamins and fortified foods supply synthetic folic acid, which requires a functional MTHFR enzyme to convert it into usable form. Carriers of common MTHFR gene variants, C677T and A1298C, have reduced MTHFR enzyme activity and convert folic acid less efficiently than those without the variants.

Open full entry →

Microsurgery is a surgical technique that uses optical magnification, either through loupes or an operating microscope, paired with fine instruments and delicate suture materials to work on small or fragile anatomical structures.¹⁸⁴ In reproductive surgery, microsurgical principles include minimal tissue trauma, precise hemostasis, tension-free anastomosis, and meticulous layer-by-layer closure.

Open full entry →

Mini-laparotomy is a small-incision open abdominal surgical approach, typically using a horizontal incision of 3 to 7 cm placed low on the abdomen, that provides direct access to pelvic structures when a laparoscopic approach is not suitable. It occupies a practical middle ground: more access than laparoscopy can offer in certain cases, substantially less morbidity than a full laparotomy.

Open full entry →

Minimally Invasive Gynecologic Surgery (MIGS) is a recognized gynecologic subspecialty focused on laparoscopic, hysteroscopic, and robotic surgical techniques for treating disorders of the female reproductive tract.¹⁸⁵¹⁸⁶ MIGS fellowship-trained surgeons complete structured advanced training in operative laparoscopy and hysteroscopy after residency, with dedicated focus on tissue-sparing and minimally invasive approaches to complex gynecologic pathology.

Open full entry →

Molimina (from Latin: exertions) is a cluster of mild, predictable premenstrual symptoms that reflect normal luteal-phase progesterone activity. Typical features include slight breast tenderness, a sense of pelvic fullness, mild fluid retention, subtle mood shifts, and premenstrual mucus changes. These symptoms arise because the corpus luteum is producing progesterone. They resolve when menstruation begins.²²⁰

Open full entry →

The Mucus Cycle is the discrete window of fertile-type cervical mucus within a single menstrual cycle, beginning at the Point of Change (the first observable shift from the dry baseline) and ending on Peak Day. The mucus cycle is the fertile window in practical terms. It is distinct from the mucus pattern, which refers to the full sequence of charted cervical observations across the entire cycle, including pre-Peak dry days, the mucus cycle itself, and post-Peak dry days. Hilgers documented this architecture in CrMS training materials, charting the mucus cycle as its own bounded phase between menstruation and post-Peak dryness.⁷⁹ The length and character of the mucus cycle varies. A shortened or atypical mucus cycle can indicate low estrogen output, cervical factor infertility, or approaching anovulation. Tracking the mucus cycle across several months reveals patterns invisible in single-cycle data.

Open full entry →

The Mucus Cycle Score (MCS) is a CrMS-derived quantitative measure that summarizes the cervical mucus observations across the pre-ovulatory phase of a single cycle to estimate the quality of estrogen-driven follicular activity for that cycle.⁷⁸ It provides a single-cycle index of mucus adequacy, derived entirely from external vulvar observations recorded through the VDRS.

Open full entry →

The mucus pattern is the recognizable sequence of cervical secretion changes that unfolds across a single menstrual cycle, observable through vulvar sensation and visual inspection. Estrogen produced by the maturing follicle stimulates cervical crypts to generate secretions that become progressively more fluid, stretchy, and lubricative as ovulation approaches. After ovulation, progesterone shifts the pattern abruptly: secretions become sparse, tacky, or absent entirely. This estrogen-to-progesterone transition marks the boundary between the pre-peak phase and the post-peak phase of the cycle.⁷⁴

Open full entry →

Mucus quality descriptors are the standardized observation vocabulary used by fertility awareness-based methods (FABMs) to describe the physical characteristics of cervical secretions at each observation point in the cycle.⁷ Different methods use different vocabulary systems. The Creighton Model FertilityCare System (CrMS) defines a specific set of standardized descriptors that encode sensation, appearance, color, and stretch into a structured chart entry.⁷ The Billings Ovulation Method uses its own descriptor language, centered on the sensation experienced at the vulva.⁷⁴ Sympto-thermal approaches also incorporate mucus descriptors alongside basal body temperature observation.

Open full entry →

Myo-inositol is a naturally occurring carbocyclic sugar that functions as a secondary messenger in insulin signaling and follicle-stimulating hormone (FSH) pathways within ovarian tissue. Its role in reproductive physiology centers on insulin sensitization: disrupted inositol metabolism is a recognized feature of the insulin resistance seen across PCOS phenotypes, particularly Phenotypes A and B, where hyperandrogenism and metabolic dysfunction overlap.⁴¹⁴²

Open full entry →

Myomectomy is the surgical removal of uterine fibroids (leiomyomas) while preserving the uterus.¹⁸³ A restorative approach favors myomectomy over hysterectomy when fibroids are contributing to infertility, recurrent pregnancy loss, or abnormal uterine bleeding, because the goal is to restore normal uterine anatomy rather than remove the organ.

Open full entry →

NaPro Medical is the non-surgical treatment arm of NaProTECHNOLOGY, using Creighton Model cycle charts to guide hormone evaluation and corrective medical care. Rather than suppressing the cycle, NaPro Medical reads it. Trained NaPro clinicians use cycle charting data to time laboratory panels to specific phases of the menstrual cycle, identify patterns of hormonal dysfunction, and develop treatment plans targeted to the underlying condition.¹¹¹²

Open full entry →

NaPro Surgery is the specialized surgical arm of NaProTECHNOLOGY, applying reconstructive pelvic surgery techniques aimed at restoring anatomy and function rather than simply removing tissue. The hallmark principles are near-adhesion-free technique, excision-based treatment of endometriosis, and fertility preservation throughout every step of the procedure.¹⁰⁸⁰

Open full entry →

NaProTECHNOLOGY (Natural Procreative Technology) is a women's health science developed by Dr. Thomas Hilgers at the Pope Paul VI Institute that monitors and maintains reproductive and gynecologic health by working cooperatively with the menstrual and fertility cycles. It uses the Creighton Model FertilityCare System to identify biological markers of cycle function, then applies targeted medical (NaPro Medical) and surgical (NaPro Surgery) treatments to correct identified abnormalities. NaProTECHNOLOGY does not employ methods that are suppressive, circumventive, or destructive of reproductive function. It is the most extensively published clinical approach within Restorative Reproductive Medicine. Sanchez-Mendez et al. (2025), in a cohort of 1,310 couples, reported cumulative live-birth rates of 50% at 24 months and 62.1% at 36 months or longer.⁹³ These figures are comparable to, or exceed, cumulative live-birth rates reported after multiple IVF cycles in equivalent populations.

Open full entry →

A NaProTechnology Medical Consultant (NFPMC) is a physician who has completed formal postgraduate training in NaProTechnology through an accredited program. Training routes include the fellowship at the Pope Paul VI Institute for the Study of Human Reproduction and the AAFCP Medical Consultant program. The credential is distinct from standard OBGYN or reproductive endocrinology training. It requires coursework in Creighton Model chart interpretation, NaPro diagnostic protocols, and NaPro surgical approaches.⁶⁴

Open full entry →

Prematurity Prevention is a NaProTechnology clinical protocol developed by Dr. Thomas W. Hilgers for managing pregnancies at elevated risk for preterm birth. It addresses a defined set of risk factors: prior preterm delivery, second-trimester pregnancy loss, cervical insufficiency, and specific obstetric histories that indicate heightened vulnerability. The Prematurity Prevention protocol is a structured approach to identifying and supporting at-risk pregnancies from early gestation rather than waiting for preterm labor to present.⁷⁸

Open full entry →

NaProTECHNOLOGY (NaPro) is the most established and extensively studied approach within Restorative Reproductive Medicine, developed by Dr. Thomas Hilgers at the Pope Paul VI Institute and built on the Creighton Model FertilityCare System. RRM is the broader paradigm: it describes any medical approach that diagnoses and treats the root causes of reproductive dysfunction in cooperation with normal physiology, without bypassing or suppressing it. NaPro practitioners may or may not identify their work under the RRM label. Other approaches sharing this philosophy include: NeoFertility, Marquette Method-based medical management, and FEMM-based care. All share a common framework: biomarker data from cycle charting guides cycle-timed evaluation, root-cause diagnosis, and restorative treatment. None use suppressive medications as primary therapy or bypass conception through assisted reproductive technology.¹

Open full entry →

Natural Family Planning (NFP) is the traditional, values-based umbrella term for methods of achieving or avoiding pregnancy by tracking the body's natural fertility signs. The term carries historical roots in Catholic teaching and healthcare, where observing the cycle was understood as cooperation with natural physiology. In clinical and secular contexts today, Fertility Awareness-Based Methods (FABMs) is the broader, more common term; NFP and FABMs overlap substantially but are not identical categories.⁶

Open full entry →

Natural fertility is the inherent biological capacity of a couple to achieve pregnancy through natural conception, without removing gametes, without external fertilization, and without bypassing any part of the reproductive system.⁸⁷ In healthy couples, the chance of conception in a given cycle is approximately 20-25%, declining with age and with unaddressed conditions such as endometriosis, tubal disease, ovulatory dysfunction, or male-factor impairment including sperm DNA fragmentation and low sperm count.³ RRM treats the conditions that have impaired natural fertility rather than substituting a laboratory step for impaired physiology. Medical treatment, surgical correction, and cycle-timed protocols support conception through native reproductive pathways. Restoring natural fertility for couples who want it is RRM's primary clinical goal.

Open full entry →

Natural killer (NK) cells are lymphocytes of the innate immune system with two populations relevant to reproductive medicine: circulating NK cells (CD56dim), which perform immune surveillance in the bloodstream, and uterine NK cells (CD56bright), which are the predominant immune cells in the endometrium during the secretory phase and early pregnancy.^[209]

Open full entry →

Near Adhesion-Free Reconstructive Pelvic Surgery (NARPS) is a surgical approach developed to systematically minimize the formation of new adhesions during and after complex pelvic surgery.⁸⁰ The central premise is that while postoperative adhesion formation cannot be eliminated entirely, it can be reduced substantially through deliberate, technique-level choices at every stage of the operation.

Open full entry →

Near-contact laparoscopy is a surgical visualization technique in which the laparoscope is positioned in close proximity to the peritoneal surface, achieving higher magnification and improved resolution compared to standard operating distance. The technique was developed to identify subtle endometriotic implants: atypical, early-stage, or non-pigmented lesions that are routinely missed when the camera is positioned at conventional distance from tissue.¹⁷⁰ Standard laparoscopy, performed at working distances of 10 cm or more, can fail to resolve the fine detail needed to characterize peritoneal abnormality accurately.

Open full entry →

NeoFertility is a restorative reproductive medicine clinical framework developed in Dublin, Ireland, that integrates cycle charting, targeted hormonal investigation, and surgical correction to identify and treat the root causes of infertility, recurrent pregnancy loss, and at-risk pregnancy.¹⁴⁶ The approach builds on the diagnostic foundation of NaProTechnology while expanding the evaluation panel to include reproductive immunology, androgen profiling, and in-depth assessment of both partners.

Open full entry →

Neosalpingostomy is a laparoscopic surgical procedure that creates a new opening at the fimbriated (distal) end of a fallopian tube that has become blocked or destroyed, typically by a hydrosalpinx. The companion procedure, fimbrioplasty, reconstructs and restores a partially obstructed or agglutinated fimbrial end where some tissue remains viable. Both address distal tubal disease, which differs anatomically and etiologically from proximal occlusion. Pelvic inflammatory disease, prior infection, and endometriosis-related adhesions are the most common causes of distal damage.

Open full entry →

Nutritional and lifestyle medicine is a clinical framework that addresses the metabolic and behavioral contributors to reproductive health, treating them as root causes rather than background factors. Diet quality, body composition, sleep, stress load, physical activity, and environmental exposures all influence hormone production, cycle regularity, sperm quality, and endometrial function. When these factors are inadequate or dysregulated, fertility is affected in measurable, addressable ways.⁷⁰

Open full entry →

OAT syndrome (oligoasthenoteratospermia) is a combined sperm parameter deficit defined by three simultaneous abnormalities: low sperm concentration (oligospermia), reduced progressive motility (asthenospermia), and abnormal morphology (teratospermia). Each parameter is measured against WHO 2021 reference values: concentration below 16 million per milliliter, progressive motility below 30%, and normal morphology below 4% by Kruger strict criteria.¹⁷¹ When all three fall below threshold together, the combined deficiency is termed OAT syndrome.

Open full entry →

An oral contraceptive (OC) is a hormone-based medication taken by mouth to prevent pregnancy. Combined oral contraceptives (COCs) contain synthetic estrogen and progestin. Progestin-only pills contain progestin alone. Both work primarily by suppressing pituitary gonadotropin release, which prevents ovulation. The monthly cycle is not regulated by these medications; it is suppressed. What appears as a period during the pill-free interval is a withdrawal bleed, not a naturally occurring menstrual cycle.

Open full entry →

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of ovarian stimulation protocols used in ART, in which pharmacologically elevated gonadotropin levels cause the ovaries to produce an excessive number of follicles, triggering systemic vascular and fluid changes that range in severity from mild bloating to life-threatening thromboembolism.⁶² Mild OHSS is common. Severe OHSS requires hospitalization and can involve ascites, pleural effusion, hemoconcentration, and renal impairment. The condition is classified by grade, and major professional society guidelines address its prevention and management.⁹⁵

Open full entry →

Ovarian reserve describes the pool of follicles currently available in the ovaries, estimated through surrogate markers: AMH, AFC, and basal FSH. Clinicians cannot count oocytes directly. These markers are proxies for follicular activity, not a permanent verdict on reproductive potential. Low AMH or low AFC signals a smaller-than-average visible follicular pool. It does not explain why, and it does not close the door on natural conception. One competent follicle per cycle is all that is needed.

Open full entry →

Oxidative stress is a cellular imbalance in which reactive oxygen species (ROS) production exceeds the body's antioxidant defenses, causing damage to lipids, proteins, and DNA.³⁵ At physiological concentrations, ROS participate normally in folliculogenesis, oocyte maturation, sperm capacitation, and early embryo development. When that balance tips toward excess, the same molecules become destructive.

Open full entry →

Partial Rupture Syndrome (PRS) is an ovulation disorder in which the dominant follicle decreases in size at the expected time of ovulation but does not fully collapse, leaving a partial cystic residual rather than completing the rupture process.⁷⁸ Rupture initiates but stalls. The oocyte-cumulus complex is not fully expelled.

Open full entry →

Patient-centered care is a healthcare orientation that places the individual's values, preferences, expressed needs, and active participation at the center of clinical decision-making, while ensuring information transparency and coordination across providers. The framework identifies several interconnected dimensions of care quality: respecting patient preferences, providing emotional support, ensuring access to information, involving family and close partners, and maintaining continuity across the care team.

Open full entry →

PCOS (Polycystic Ovary Syndrome) is the most common endocrine disorder in reproductive-age women, affecting approximately 10-13% of this population worldwide.³⁹ Diagnosis requires two of three Rotterdam criteria: oligo- or anovulation, clinical or biochemical signs of hyperandrogenism (elevated androgens causing acne, hirsutism, or irregular cycles), and polycystic ovarian morphology on ultrasound.⁹⁴ Insulin resistance, present in the majority of affected women regardless of BMI, is a central pathophysiologic driver that sustains androgen overproduction, follicular arrest, and anovulation. In NaProTECHNOLOGY and RRM practice, PCOS is approached restoratively: lifestyle modification and dietary changes to address insulin resistance (a 5% reduction in body weight can restore ovulation in overweight patients), insulin sensitization with agents such as metformin or myo-inositol, cycle charting and ovulation monitoring, targeted hormonal support, and in refractory cases, laparoscopic ovarian wedge resection. Long-term hormonal suppression is not a restorative treatment for PCOS.

Open full entry →

PCOS phenotypes are the four distinct clinical subtypes of polycystic ovary syndrome (PCOS), defined by the 2003 Rotterdam consensus based on which combination of three diagnostic criteria a patient presents. The three criteria are hyperandrogenism (clinical or biochemical), ovulatory dysfunction, and polycystic ovarian morphology (PCOM) on ultrasound. A PCOS diagnosis requires any two of the three. That two-of-three requirement produces four possible combinations, each designated a phenotype.⁹⁴³⁹

Open full entry →

Peak Day is the last day in a menstrual cycle on which cervical mucus is clear, stretchy (like raw egg white), or lubricative, and is used as a primary ovulation reference point in mucus-based fertility awareness methods, including the Creighton Model FertilityCare System.⁸ Peak Day correlates closely with follicular rupture, occurring within plus or minus two days of ovulation in approximately 95% of cycles.⁸ Crucially, Peak Day is identified retrospectively: a woman recognizes it the day after it occurs, when fertile-type mucus has ceased. The day after Peak Day is called post-peak day 1 (P+1). In NaProTECHNOLOGY, Peak Day is the reference anchor for cycle-timed diagnostic blood draws, particularly the post-peak day 7 (P+7) progesterone and estradiol measurements used to evaluate luteal phase adequacy. Accurate Peak Day identification is foundational to NaPro hormonal support protocols and to the diagnostic value of the entire charting system.

Open full entry →

The peak symptom is the last day in a menstrual cycle on which cervical mucus is observed as clear, stretchy, or lubricative, regardless of the total amount of discharge present. Quality is the marker, not volume. A day with abundant but cloudy or tacky mucus does not qualify. A day with minimal but clear or lubricative discharge does. This distinction matters because the peak symptom identifies the end of the fertile window with precision: research shows ovulation typically occurs within 24 to 48 hours before or after this day.¹⁰⁰

Open full entry →

PEARS (Pelvic Excision And Repair Surgery) is a form of plastic reconstructive surgery of the pelvis developed by Dr. Thomas Hilgers at the Pope Paul VI Institute.⁷⁸ The name reflects the procedure's dual mandate: complete excision of pelvic disease and systematic anatomic repair.

Open full entry →

Pelvic adhesions are bands of fibrous scar tissue that form between pelvic structures following inflammation, infection, endometriosis, or prior surgery, tethering organs that should move freely relative to one another. They distort anatomy, restrict tubal and ovarian mobility, impair sperm and ovum transport, and generate chronic pain through mechanical traction on innervated tissue.

Open full entry →

Pelvic floor physical therapy (PFPT) is a specialized rehabilitation discipline that evaluates and treats musculoskeletal contributors to chronic pelvic pain, dyspareunia, voiding and bowel dysfunction, and post-surgical or postpartum pelvic floor impairment. Pelvic floor therapists assess hypertonic or hypotonic pelvic floor muscles, myofascial trigger points, scar tissue restrictions, and neuromuscular coordination patterns. Treatment addresses the physical layer of conditions that also have gynecologic or hormonal contributors.²⁰⁸

Open full entry →

Perimenopause is the biological transition period preceding menopause, typically spanning 4 to 10 years, during which ovarian function declines progressively and menstrual cycle patterns become irregular. The staging criteria established by the Stages of Reproductive Aging Workshop (STRAW+10) define early perimenopause by variable cycle length and late perimenopause by cycles 60 or more days apart, concluding at the final menstrual period.²¹⁸ This transition follows biology, not a specific calendar age, though it most commonly begins in the mid-forties.

Open full entry →

In RRM, personalized treatment is built on what the diagnostic evaluation finds, not on the presenting symptom. No two couples with infertility have the same diagnosis, and treatment in RRM reflects that. Plans are assembled from cycle-timed diagnostics and may include targeted hormonal therapy, ovulation induction, luteal phase support, nutritional and lifestyle prescription, and specialized surgery.³ Patient goals shape surgical decisions: a woman who wants future fertility and a woman who does not require different approaches to the same structural finding. Male-partner treatment is personalized in the same framework -- varicocele repair timing, antioxidant protocols, and hormonal correction are determined by each man's specific workup, not a uniform andrology algorithm.¹

Open full entry →

PGT-A (Preimplantation Genetic Testing for Aneuploidy) is a laboratory procedure performed on an embryo biopsy during IVF to screen for chromosomal aneuploidy before transfer. Cells are removed from the trophectoderm of a blastocyst and analyzed by next-generation sequencing or array comparative genomic hybridization to determine chromosomal copy number. Embryos classified as euploid (chromosomally normal) are selected for transfer; aneuploid embryos are typically discarded or frozen and not transferred.

Open full entry →

The Point of Change (POC) is the cycle day when a woman's Base Infertile Pattern is broken for the first time: discharge changes in character, sensation shifts, and the fertile window opens.⁷⁴

Open full entry →

Poor cervical mucus production is a reduction in the quantity, quality, or fertile-window duration of cervical mucus that impairs sperm ascent and reduces the effective fertile window. Fertile-type mucus, characterized by clear, fluid, stretchy secretions, creates a biological channel for sperm transport and filters morphologically abnormal sperm. When this mucus is absent or limited, fertilization potential falls even when ovulation is otherwise occurring.⁷⁴

Open full entry →

The post-peak phase is the portion of the menstrual cycle that runs from the day after Peak Day through the last day before the next menstrual bleed, corresponding to the progesterone-dominant luteal period. Once the peak symptom has passed and ovulation has occurred, progesterone produced by the corpus luteum takes over. Cervical secretions become sparse or absent. The mucus pattern shifts from fertile to non-fertile within a matter of days.

Open full entry →

Postpartum fertility refers to the return of ovulatory cycles and conception potential following childbirth, a process shaped significantly by breastfeeding behavior and the hormonal transition out of the postpartum state. Breastfeeding suppresses ovulation through sustained prolactin elevation, delaying cycle return by weeks to months depending on feeding frequency and exclusivity. The lactational amenorrhea method (LAM) relies on this biology: exclusive breastfeeding, amenorrhea, and age of the infant under six months together provide highly effective contraception, with effectiveness exceeding 98% when all three criteria apply.²⁰⁷

Open full entry →

The pre-peak phase is the portion of the menstrual cycle that runs from the first day of menstruation through and including Peak Day, encompassing the follicular and periovulatory period. During this phase, estrogen rises progressively as a follicle matures, driving the mucus pattern from absent to increasingly fertile in quality. Cervical secretions become more fluid, stretchy, and lubricative as the cycle approaches the peak symptom.

Open full entry →

Premature Ovarian Insufficiency (POI) is the loss of normal ovarian function before age 40, characterized by amenorrhea, elevated FSH, and reduced estrogen production. The diagnosis requires two FSH measurements above 25 IU/L taken at least four weeks apart in the context of menstrual irregularity or absence before age 40.⁷³ POI is distinct from diminished ovarian reserve (DOR), where reserve is reduced but follicular activity continues, and from natural menopause, which occurs in the fifth decade.

Open full entry →

Premenopause is the reproductive life stage preceding perimenopause, spanning the years of regular ovulatory cycling from adolescence through the late thirties or early forties. Hormonal patterns during premenopause are comparatively stable: estradiol and progesterone follow predictable monthly rhythms, FSH remains within normal range, and AMH sits at or near its lifetime peak. This is the window of highest natural fertility for most women.

Open full entry →

Premenstrual Bleeding (PMB) is a Creighton Model biomarker consisting of brown spotting or light bleeding that appears before the onset of true menstrual flow, on days that should be post-Peak infertile days.⁴⁴

Open full entry →

Premenstrual syndrome (PMS) is a pattern of cyclical physical, cognitive, and emotional symptoms that appear in the luteal phase of the menstrual cycle and resolve with or shortly after the onset of menses. Common features include irritability, mood lability, bloating, breast tenderness, fatigue, and difficulty concentrating. The defining characteristic is the cyclical pattern: symptoms appear predictably after ovulation and clear with menstruation.^[66]

Open full entry →

Recurrent Pregnancy Loss (RPL) is defined as two or more clinical pregnancy losses before 20 weeks of gestation. RPL is clinically distinct from isolated early pregnancy loss: a single loss is common and often attributable to sporadic chromosomal error, while recurrent loss warrants systematic evaluation for treatable maternal and paternal contributors. Assessment includes peripheral karyotype analysis of both partners, antiphospholipid antibody testing, uterine anatomical evaluation (SHG, HSG, or hysteroscopy), thyroid and prolactin screening, and evaluation for hereditary thrombophilias. RRM pursues identification of underlying conditions including hormonal (progesterone deficiency, thyroid dysfunction), anatomical (isthmocele, septum, fibroids), immunologic (APS, NK cell activity), and metabolic factors. RPL affects an estimated 2 to 5% of couples attempting pregnancy.³⁶³⁷

Open full entry →

Reproductive Endocrinology is the study of hormonal regulation of reproduction, encompassing the hypothalamic-pituitary-gonadal axis and its effects on ovulation, implantation, and pregnancy maintenance. As a conventional subspecialty, Reproductive Endocrinology and Infertility (REI) developed with close ties to assisted reproductive technology, making IVF a central clinical pathway for many fellowship-trained practitioners. Restorative reproductive medicine, in practices such as NaProTechnology and NeoFertility, applies the same endocrine science to a different goal. Hormonal evaluation is timed to cycle phases identified through cycle-timed diagnostics rather than drawn on arbitrary calendar dates, and findings direct restorative treatment rather than bypass procedures. Conditions such as hypothyroidism, hyperprolactinemia, diminished ovarian reserve, and hormonal abnormalities that contribute to infertility or pregnancy loss are identifiable through targeted endocrine workup and are treated at the source.²³ Key hormones in this evaluation include FSH, LH, TSH, and hCG, each interpretable only within the context of the cycle phase at the time of the draw.

Open full entry →

Reproductive health optimization is the overarching RRM goal of improving the overall health and function of the reproductive system, encompassing fertility, cycle regularity, absence of pain or abnormal bleeding, hormonal balance, and long-term gynecologic wellness. Achieving pregnancy is a result of restored health, not a standalone procedural endpoint.¹ The menstrual cycle itself carries independent health value: regular ovulation protects bone density, cardiometabolic function, and mood across a woman's lifespan.⁸⁹ For this reason, RRM serves women who are not trying to conceive as fully as those who are. Male reproductive health optimization follows the same logic: sperm quality, hormonal health, and lifestyle factors are evaluated and treated as part of couple-centered care.

Open full entry →

The Reproductive Health Research Institute (RHRI) is a research and training organization focused on fertility-awareness-based medicine, founded to generate peer-reviewed evidence supporting cycle-informed clinical practice.¹⁴⁵ RHRI is the academic arm of the FEMM framework. Its published work spans FABM method efficacy, the health significance of chronic anovulation, and hormonal biomarker evaluation relevant to reproductive conditions including PCOS, thyroid-related cycle disruption, and immune-mediated pregnancy loss.

Open full entry →

Reproductive Immunology is the study of immune system contributions to implantation failure, recurrent pregnancy loss, and fertility-related conditions. Research in this field has clarified several immune pathways relevant to reproductive outcomes. Antiphospholipid syndrome (APS) elevates thrombotic risk at implantation sites and is a treatable cause of recurrent pregnancy loss.⁵² Elevated uterine natural killer cell activity and autoimmune and thrombophilic disorders appear in a subset of couples with otherwise unexplained implantation failure.³⁷ Chronic endometritis disrupts the endometrial environment and associates with recurrent implantation failure and pregnancy loss.²⁶ The endometrial microbiome is an adjacent area of investigation: microbial imbalance in the uterine environment correlates with implantation outcomes independent of structural pathology.⁶⁵ RRM clinicians may incorporate reproductive immunology evaluation when the clinical picture suggests an immune contributor, particularly in couples with recurrent pregnancy loss or thrombophilia.

Open full entry →

In RRM, 'restorative' refers to the goal of repairing, healing, and optimizing the natural function of the reproductive system, in contrast to suppressive or bypass approaches. The restorative approach contrasts with suppressive therapies (e.g., hormonal contraception used to mask cycle symptoms) and bypass therapies (e.g., IVF circumventing tubal disease without treating it). It encompasses removal of problematic devices, reversal of prior procedures such as tubal ligation, and male-side correction such as varicocele repair. Each intervention works with the body's biology rather than substituting for it.¹ The term is specific to RRM and does not appear in standard medical classification systems. Clinicians across multiple specialties apply the principle, but reproductive medicine has made it most explicit as a framework for guiding both diagnosis and treatment decisions.

Open full entry →

Restorative Andrology is an approach to male fertility evaluation and treatment that prioritizes identifying and correcting the underlying causes of male factor infertility rather than bypassing them with sperm-retrieval procedures. Male factor is the sole cause of infertility in approximately 20% of couples and a contributing factor in another 30-40%.¹⁹³ Identifiable and correctable causes include varicocele (the most common treatable male factor), sperm DNA fragmentation, oxidative stress, hormonal imbalance, and ductal obstruction.¹⁹³⁵⁵³ Surgical correction restores the male partner's contribution to natural conception where anatomy or obstruction is the underlying problem.⁵³¹²⁵ Vasectomy reversal is a restorative option for couples where prior vasectomy is the barrier. Full semen analysis per WHO reference criteria is the starting point for male evaluation.¹⁷¹ Restorative andrology stands in contrast to the standard convention of proceeding directly to ICSI, which bypasses male pathology without treating it and carries procedural risks of its own.⁶³

Open full entry →

Restorative Reproductive Medicine (RRM) is a specialized field of medicine that identifies and treats the underlying health conditions causing reproductive dysfunction in women and men, working with the body's natural physiology rather than bypassing or suppressing it.¹ RRM applies across the reproductive lifespan to conditions including infertility, recurrent miscarriage, PCOS, endometriosis, PMS/PMDD, irregular or painful periods, hormonal dysfunction, male factor conditions, and perimenopause. Care draws on cycle charting as a clinical diagnostic instrument, targeted medical workup, hormone and pharmacologic therapies, restorative surgery and andrology, and lifestyle interventions.² RRM is an umbrella field. NaProTechnology is one well-developed method within it; others include FEMM Medical Management and NeoFertility. The goal is a body functioning at its healthy physiologic state, with fertility restored as a natural outcome of that health.³

Open full entry →

Root cause diagnosis is the foundational RRM principle that reproductive health problems (including infertility, abnormal bleeding, and chronic pain) are symptoms of identifiable underlying causes, not final diagnoses in themselves.⁴ Underlying causes may include hormonal imbalances, structural abnormalities (e.g., tubal blockage, uterine defects), inflammatory conditions, autoimmune disorders, metabolic dysfunction, iatrogenic factors such as C-section scar defects, or male-factor contributions such as sperm DNA fragmentation and varicocele. Both partners are evaluated systematically, including semen analysis with DNA fragmentation index. RRM does not accept "unexplained infertility" as a final answer. That label almost always means under-investigated.³

Open full entry →

S-MAP (Systematic Mapping of the Abdomen and Pelvis) is an operative protocol developed within NaProTechnology and refined by IIRRM-trained surgeons that requires a structured, sequential inspection of all abdominal and pelvic regions before any surgical intervention begins. The protocol establishes a reproducible examination sequence: every anatomic region is evaluated before excision, lysis, or reconstruction, so that no area of disease is passed over in the urgency of addressing the most visible pathology first.

Open full entry →

A Saline Infusion Sonohysterogram (SIS) is a transvaginal ultrasound procedure in which sterile saline is infused into the uterine cavity to enhance visualization of the endometrium and detect structural abnormalities inside the uterus. By distending the cavity with fluid, the clinician gains a clear acoustic window that a standard pelvic ultrasound cannot provide. SIS detects endometrial polyps, submucosal fibroids, intrauterine adhesions, uterine septa, and can reveal an isthmocele (cesarean scar defect), including measurable defect dimensions and residual myometrial thickness.^1516160

Open full entry →

Secondary infertility is the inability to conceive after 12 months of regular, unprotected intercourse (or 6 months for women 35 or older) in a couple who has previously achieved at least one pregnancy, regardless of the outcome of that prior pregnancy. It is more common than many clinicians acknowledge. And it is too often met with the worst possible clinical response: reassurance that prior success means nothing is wrong.

Open full entry →

Selective salpingography is a fluoroscopic or hysteroscopic procedure in which a catheter is guided through the cervix and selectively positioned at the tubal ostium of each fallopian tube, allowing contrast dye to be injected into each tube individually to assess patency. Unlike a standard hysterosalpingogram (HSG), which fills both tubes simultaneously from the uterine cavity, selective salpingography isolates each tube to evaluate the proximal segment with greater precision.⁸⁴¹⁶¹

Open full entry →

Semen analysis is the primary initial laboratory assessment for male-factor infertility, evaluating sperm concentration, total motility, progressive motility, morphology, semen volume, and additional parameters according to World Health Organization reference criteria.¹⁷¹ It is among the first investigations ordered when a couple presents with difficulty conceiving, reflecting that male factor is the sole cause in approximately 20% of couples and a contributing cause in an additional 30 to 40%.

Open full entry →

A shortened luteal phase is a post-ovulatory phase lasting fewer than 11 days, measured from the day of confirmed ovulation (Peak Day) through the onset of the next menstruation. The luteal phase exists to sustain the hormonal environment needed for implantation: the corpus luteum produces progesterone, and a curtailed phase compresses the window available for endometrial preparation and embryo attachment. Shortened luteal phase is one differential within the broader evaluation of luteal phase deficiency.⁴⁴⁴⁵

Open full entry →

Sonographic ovulation classification is a serial transvaginal ultrasound framework, developed within NaProTechnology practice, that characterizes the quality of the periovulatory event and distinguishes anatomically normal ovulation from six distinct pathological patterns and one anovulatory variant.

Open full entry →

Sperm DNA Fragmentation Index (DFI) is a measure of the proportion of sperm with damaged or broken DNA strands. Standard semen analysis evaluates sperm count, motility, and morphology. It does not assess DNA integrity. A semen sample can appear normal on standard analysis while carrying a high burden of DNA strand breaks.¹⁹

Open full entry →

Sperm DNA fragmentation (extended) refers to the assay methods used to measure strand breaks and chromatin damage in sperm DNA beyond what standard semen parameters detect. The principal platforms are SCSA (Sperm Chromatin Structure Assay), TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling), COMET assay, and sperm chromatin dispersion (SCD). Each measures DNA damage through a different mechanism, and each carries a distinct sensitivity profile.¹⁹²¹ The clinical concern threshold varies by assay; no single universal cutoff applies across platforms.

Open full entry →

The sympto-hormonal method is a fertility awareness-based method (FABM) that combines physical fertility signs, specifically cervical mucus observation and basal body temperature, with objective urinary hormone testing to identify the fertile window and confirm ovulation.⁶ The urinary tests typically measure LH (luteinizing hormone) and estrone-3-glucuronide (E1G), a urinary estrogen metabolite. Together, these markers provide both a hormonal lead signal before ovulation and a biochemical confirmation after it.

Open full entry →

The Sympto-Thermal Method (STM) is a fertility awareness approach that combines observation of cervical mucus changes with basal body temperature (BBT) tracking to identify both the opening and closing of the fertile window within each cycle. Cervical mucus signs identify the beginning of the fertile phase as estrogen rises; the sustained rise in basal body temperature after ovulation confirms that the fertile phase has ended, as progesterone from the corpus luteum elevates resting temperature by approximately 0.2 to 0.5 degrees Celsius.

Open full entry →

Tail-End Brown Bleeding (TEB) is a Creighton Model biomarker defined as two or more days of brown or black discharge at the conclusion of menstrual flow, after the heavier bleeding days have passed.⁷⁸

Open full entry →

The Peak Plus Series is a NaProTechnology and Creighton Model protocol of serial serum progesterone draws timed to specific days after the identified Peak Day, designed to characterize progesterone production across the full arc of the luteal phase rather than at a single point in time.

Open full entry →

Thyroid-Stimulating Hormone (TSH) is secreted by the anterior pituitary gland and regulates the thyroid's output of thyroxine (T4) and triiodothyronine (T3). When thyroid hormone output falls, TSH rises. When output is excessive, TSH falls. It is the primary screening marker for thyroid dysfunction.

Open full entry →

Time to pregnancy (TTP) is the number of months from the start of unprotected intercourse attempting conception to the achievement of a confirmed pregnancy, and it is the primary population-level measure of couple fecundability. In couples with normal fertility using fertility-aware, timed intercourse, studies estimate that approximately 81% conceive within 6 cycles and 92% within 12 cycles.¹⁹⁷ These probabilities decline with advancing age. When a couple has not conceived after 12 months of appropriately timed attempts, or 6 months at age 35 or older, infertility evaluation is indicated.⁸⁷

Open full entry →

Transcervical catheterization of the fallopian tubes (TCFT) is a procedure that advances a specialized catheter-guidewire system through the cervix and uterine cavity to the uterotubal junction, under fluoroscopic guidance, to diagnose and clear partial proximal tubal occlusion. It is performed in conjunction with selective salpingography and intratubal pressure measurement, which together distinguish true mechanical obstruction from spasm or contrast artifact.⁸⁴

Open full entry →

Transdermal estrogen is estradiol delivered through the skin via patch, gel, or cream, bypassing first-pass hepatic metabolism. Unlike oral estrogen, which passes through the liver before reaching systemic circulation, transdermal delivery maintains estradiol-to-estrone ratios closer to premenopausal physiological levels. This pharmacokinetic difference reduces hepatic stimulation of coagulation factors, C-reactive protein, and triglycerides, which has clinical relevance for women with thrombophilic risk factors, metabolic concerns, or elevated cardiovascular risk.²³⁰

Open full entry →

Tubal factor infertility is infertility caused by structural or functional damage to the fallopian tubes, including proximal or distal occlusion, peri-tubal adhesions, post-infectious scarring, and tube-damaging sequelae of prior surgery.⁴⁷ It accounts for a substantial proportion of female-factor diagnoses and is frequently under-investigated when couples are routed toward assisted reproduction before anatomy has been fully evaluated.

Open full entry →

Tubal ligation reversal (tubo-tubal anastomosis) is a microsurgical procedure that reconnects the segments of the fallopian tube separated or occluded during prior sterilization, restoring natural tubal patency and allowing natural conception to resume. The surgery involves precise re-anastomosis of the two tubal ends under magnification, with meticulous attention to lumen alignment and mucosa-to-mucosa apposition. It can be performed laparoscopically, robotically, or via mini-laparotomy.

Open full entry →

"Unexplained infertility" is a clinical label assigned when standard evaluation, which typically includes semen analysis, ovulation assessment, hormonal screening, and tubal patency testing, returns normal results. It affects an estimated 15 to 25% of couples presenting for infertility care. RRM does not accept this as a final diagnosis. In RRM, unexplained means undiagnosed.

Open full entry →

Uterine fibroids, or leiomyomas, are benign smooth-muscle tumors of the uterus that are classified by their anatomic location, which directly determines their fertility impact.¹⁸³ They are among the most common findings in reproductive-age women and range from clinically insignificant to a primary driver of implantation failure and pregnancy loss depending on their size, number, and relationship to the uterine cavity.

Open full entry →

An isthmocele (also called a cesarean scar defect or uterine niche) is a myometrial deficiency at the anterior wall of the lower uterine segment, occurring at the site of a prior cesarean scar where the uterine wall failed to heal with full thickness. The defect creates a pouch where menstrual blood pools and drains slowly, producing the characteristic symptom of prolonged post-menstrual brown spotting. Blood retained in the niche creates a microenvironment hostile to sperm transit and may impair embryo implantation, contributing to secondary infertility and elevated early pregnancy loss risk in women with an inadequate residual myometrial wall.¹⁵¹⁶³⁴

Open full entry →

A uterine septum is a fibromuscular band of tissue that partially or completely divides the uterine cavity, arising from incomplete resorption of the Mullerian ducts during fetal development. It is the most common congenital uterine anomaly. A septum does not alter the external uterine contour, distinguishing it from a bicornuate uterus.

Open full entry →

The Vaginal Discharge Recording System (VDRS) is the structured observation-and-coding framework used in the Creighton Model FertilityCare System to convert each day's cervical mucus observation into a standardized chart entry that any trained clinician can read and interpret consistently.⁷ Each observation combines a mucus type descriptor, stretch measurement, color category, and sensation qualifier into a coded record.⁶⁴

Open full entry →

A varicocele is an abnormal dilation of the pampiniform plexus veins within the scrotum, present in approximately 15% of men in the general population and in 35% or more of men evaluated for infertility.⁵³ The enlarged veins impair the countercurrent heat-exchange mechanism that keeps the testis cooler than core body temperature. This thermal dysregulation suppresses spermatogenesis and amplifies oxidative stress, damaging sperm DNA and reducing both sperm concentration and motility.³⁵

Open full entry →

Vasectomy reversal is microsurgical reconnection of the vas deferens after prior vasectomy, restoring the pathway for sperm to reach the ejaculate and enabling natural conception. Two techniques exist. Vasovasostomy joins the cut ends of the vas deferens directly and applies to most cases. Vasoepididymostomy bypasses the vas deferens and connects directly to the epididymis; surgeons must use it when secondary epididymal obstruction has developed upstream, a complication more common with longer obstructive intervals. The choice is made intraoperatively based on fluid analysis and is not determined in advance.

Open full entry →

Vulvar observation is the practice of assessing cervical secretions at the external vulva, using folded white tissue and attention to sensation, appearance, and elasticity of any discharge present.⁷ It is the primary data-collection step in several FABMs, including the Creighton Model FertilityCare System, the Billings Ovulation Method, and FEMM. The observation is performed at each bathroom visit throughout the day.

Open full entry →

The window of implantation (WOI) is the hormonally defined period during the secretory phase of the menstrual cycle when the endometrium becomes receptive to a developing embryo. Receptivity arises from progesterone exposure following ovulation, which triggers secretory transformation of the endometrial lining. Without adequate ovulation and normal corpus luteum function, the secretory transformation is incomplete and receptivity is impaired.⁴⁴

Open full entry →