Comparison of Cumulative Live Birth Rates Per Aspiration IVF/ICSI Cycle Between GnRH Antagonist Protocol and Progesterone-Primed Ovarian Stimulation Protocol for Infertility With Normal Ovarian Reserve: A Randomised Controlled Trial

Background: Oral progestin has been used to prevent premature ovulation during follicle stimulation protocols performed in combination with a freeze-only strategy. However, no studies have determined how oral progestin clinically compares to gonadotropin-releasing hormone (GnRH) antagonists in women with normal ovulation. This study aimed to compare the efficacy and safety of controlled ovarian stimulation between progestin-primed ovarian stimulation (PPOS) protocol and GnRH antagonist (GnRH-ant) protocol.Methods: Young women with infertility and normal ovarian reserve who underwent in vitro fertilisation (IVF) treatments were screened and randomly allocated to the PPOS or GnRH-ant group. Women in the PPOS group underwent freeze-all and delayed embryo transfer, whilst fresh embryo transfer was preferred for those in the GnRH-ant group. The primary endpoint was the cumulative live birth rate (CLBR). Secondary endpoints included the incidence of premature luteinising hormone (LH) surge and the number of viable embryos.Results: CLBRs were similar in the PPOS and GnRH-ant group (55.75% vs. 52.87%, respectively, P > 0.05). No premature LH surge was observed during ovarian stimulation in the PPOS group, although six (3.45%) cases were observed in the GnRH-ant group. On the trigger day, LH level was lower in the PPOS group than in the GnRH-ant group (2.30 ± 1.78 mIU/ml vs. 3.66 ± 3.52 mIU/ml, P < 0.01). There were no differences in the number of retrieved oocytes, mature oocytes, or viable embryos between the two groups. Other clinical outcomes including implantation rates (37.27% vs. 36.77%), clinical pregnancy rates (55.75% vs. 55.89%), and miscarriage rates (12.28% vs. 13.76%) were comparable between the PPOS group and GnRH-ant group (P > 0.05). There was also no significant differences in newborn weights for singleton or twin births between the two groups (P > 0.05).Conclusion: Live birth outcomes are similar for PPOS and GnRH antagonist protocols in women with normal ovarian reserve. PPOS is likely to play a promising role in the freeze-only strategy given its simplicity and convenience for the patient. Trial registration: This trial was registered in the China Clinical Trial Registry on September 6, 2018 (number: ChiCTR1800018246).