Abstract
BACKGROUND: Infertility affects 8%-12% of couples worldwide; advanced maternal age combined with diminished ovarian reserve (DOR) significantly lowers IVF success. The flexible GnRH-antagonist and progestin-primed ovarian stimulation (PPOS), are increasingly adopted for freeze-all strategies in this poor-prognosis population; however, their relative effectiveness remains inconclusive. METHODS: This retrospective study (January 2017-April 2022) enrolled only women ≥ 35 years with diminished ovarian reserve (AMH < 1.2 ng/mL and/or AFC < 5). Two controlled ovarian stimulation protocols were compared: the flexible GnRH-ant protocol and the PPOS protocol. The participants were matched using propensity score matching (PSM) based on age, body mass index (BMI), anti-Müllerian hormone (AMH) level, and antral follicle count (AFC). We compared the ovarian responses to controlled ovarian stimulation treatments and assessed the pregnancy outcomes after FET between the two groups. RESULTS: This study included 141 patients with DOR who underwent the flexible GnRH-ant protocol (n = 58) or PPOS protocol (n = 83). In oocyte retrieval cycles, the flexible GnRH-ant group had higher numbers of retrieved oocytes, MII mature oocytes, normally fertilized oocytes, cleaved embryos, available embryos, and good-quality embryos than the PPOS group (all p < 0.001). However, in FET cycles, the two groups had similar rates of good-quality embryos and clinical outcomes. There were no significant differences between the flexible GnRH-ant protocol and PPOS protocol in clinical pregnancy rate, live birth rate, and chemical pregnancy rate. The implantation rate was also higher in the flexible GnRH-ant protocol (74.5% vs. 60.7%, p < 0.001). CONCLUSION: Although the quality and quantity of the embryos was different, the good-quality embryo rate and pregnancy outcomes were similar in FET cycles between the flexible GnRH-ant protocol and PPOS protocol in advanced maternal age with DOR.