Reproductive Biology Insights

Case presentation of a healthy G2P2 patient in her late 30s, treated with in vitro fertilization–intracytoplasmic sperm injection for severe male factor infertility. The patient was treated with a gonadotropin-releasing hormone antagonist cycle (GnRH-An). GnRH-An (Cetrorelix) daily injections were started on cycle day 7 and switched to a different GnRH-An preparation (Ganirelix) due to an allergic reaction. Serum hormone levels and ultrasound monitoring were uneventful until day 13, when a corpus luteum cyst was detected, in addition to multiple intact follicles. Serum progesterone increased to 45 nmol/L, while serum luteinizing hormone (LH) remained low. Thirty-six hours following a day 13 human chorionic gonadotropin (HCG) triggering, 18 cumulus-oocyte complexes were successfully retrieved, resulting in the development of two blastocysts. This is an example for an isolated single-follicle ovulation without compromising the rest of the cohort. A possible explanation is an increased concentration of LH receptors on a specific follicle or increased sensitivity to endogenous GnRH in GnRH-An cycles. Clinicians facing a similar scenario should consider not cancelling the cycle in case additional intact follicles are present.