Human Chorionic Gonadotropin (hCG)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 13, 2026

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.

Structurally, hCG closely resembles LH. It binds the same receptors. This structural similarity is the basis for two therapeutic applications in RRM practice: exogenous hCG can substitute for the mid-cycle LH surge to trigger ovulation, and serial post-Peak injections can provide ongoing luteal phase support when corpus luteum function is suboptimal. Both are cycle-timed, cause-based interventions. The goal is supporting what the body is trying to do, not overriding it.

In recurrent pregnancy loss, hCG supplementation in early pregnancy has been studied as a support strategy. Quenby and Farquharson published a randomized controlled trial of 81 women with idiopathic recurrent loss. In women with oligomenorrhea, hCG supplementation raised the pregnancy success rate from 40% to 86%, a statistically significant improvement. No benefit was seen in women with regular cycles.¹ The implication for RRM practice: cycle type matters. Evaluation before treatment matters.

Serial quantitative hCG levels in early pregnancy are a critical early monitoring tool. A doubling time slower than expected, or a plateau, prompts investigation rather than watchful waiting. That proactive posture is part of what distinguishes RRM care in early pregnancy.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.