P-608 Cumulative live birth rates after 3 consecutive embryo transfers in freeze-all cycles following gonadotropin-releasing hormone antagonist protocol versus progesterone-primed ovarian stimulation

Abstract Study question Do cumulative live birth rates in freeze-all cycles differ between gonadotropin-releasing hormone (GnRH) antagonist protocol and progesterone-primed ovarian stimulation (PPOS)? Summary answer GnRH antagonist and PPOS protocols have similar cumulative live birth rates in freeze-all cycles. What is known already GnRH antagonists and progesterone have been used for pituitary suppression in ovarian stimulation cycles. While PPOS protocol has the advantage of oral usage and lower cost, data regarding the laboratory and clinical outcome is limited and confounding. Freeze-all cycles might provide a better model to assess the impact of PPOS protocol and GnRH antagonist protocol on laboratory, clinical outcomes and cumulative live birth rates. Study design, size, duration A retrospective cohort study on IVF cycles performed (n = 568) between January 2020 and May 2022.The entire cohort of embryos were cryopreserved at the blastocyst stage.Inclusion criteria were 18-42 years of age,ICSI for severe male factor infertility.Exclusion criteria were PGD and severe endometriosis.Indications for cryopreservation in the antagonist group were high ovarian response (n:102),endometrial polyps (n:34),high follicular phase P4(n:48) and elective purposes(n:260).PPOS was used due to a transient shortage of GnRH antagonist in the market (n:124). Participants/materials, setting, methods 568 women (GnRH antagonist:444; PPOS:124) were included in the analysis.The primary outcome was the cumulative live birth rate (CLBR) after 3 consecutive embryo transfer cycle, and the secondary outcome parameters were the number of M-II oocytes, fertilization rate and blastocyst utilization rate. Student’s t-test was used for normally distributed continuous data and Fisher’s exact tests for categorical data were used. A generalized estimating equation model and logistic regression analysis were performed to adjust for confounding factors. Main results and the role of chance The mean age of the GnRH antagonist group was 34.1 ± 5.3 and 34.5 ± 5.7 years in PPOS group (p = 0.38). The baseline characteristics including BMI, serum AMH levels, duration of infertility, duration of stimulation and gonadotropin ampules used were similar in both groups. Estradiol and progesterone levels at the time of ovulation trigger were higher in GnRH antagonist cycles (2383.5 ± 1375.4 vs 2034.5 ± 1218.3, p = 0.02 and 0.7 ± 0.6 vs 0.5 ± 0.4, p = 0.01, respectively) The mean number of cumulus-oophorus complexes (12.9 ± 7.4 vs 11.5± 10.0, p = 0.61), M-II oocytes (10.0± 6.1 vs 9.1± 6.1, p = 0.14), frozen blastocysts (4.8± 3.5 vs 4.7± 3.6, p = 0.71) were similar between GnRH antagonist and PPOS groups, respectively. Fertilization rates (84.4% vs 87.2%, p = 0.12) and blastocyst utilization rates (63.4% vs 65.9%, p = 0.34) were also similar between GnRH antagonist and PPOS groups, respectively. The number of transferred embryos and the number of unused blastocysts were similar between groups. The CLBRs after one IVF cycle and 3 consecutive frozen-thawed blastocyst transfers were comparable in GnRH antagonist and PPOS cycles (56.8% and 53.2%, p = 0.37, respectively). Limitations, reasons for caution This was a retrospective study with relatively small sample size performed at a single fertility center, which may limit the generalizability of our findings. Wider implications of the findings If the fresh embryo transfer is not intended, PPOS protocol can be used in all patient types with cost-effective and patient-friendly manner. Trial registration number 2024.013.IRB2.012