PurposeTo determine whether the cycle regimens that are used for endometrial preparation are associated with the birthweight (BW) after assisted reproductive technology (ART) using frozen‐thawed embryo transfer (FET).MethodsThe BW of singletons who were born by ART using FET was compared retrospectively, according to whether a FET was conducted in a hormone replacement therapy cycle (HRT, n = 403) or an ovulatory cycle (OVL, n = 117). The BW after timed intercourse (NAT, n = 162) also was investigated.ResultsThere were no significant differences in the age of the mothers, percentage of primiparas, gestational periods, Body Mass Index, and sex ratio between the HRT and OVL cycles. The average BW from HRT was significantly greater than that of OVL. The BW from HRT was also greater, compared with NAT, while statistical significance was not achieved between OVL and NAT. The putative factors affecting the BW, such as ovarian stimulation protocols, endometrial thickness, and the stage and quality of embryos, could not explain the difference in the BW between the HRT and OVL cycles.ConclusionAn increased BW from ART using FET seems to be ascribable to conditions of the endometrium, but not cryopreservation procedures per se, which might provide a mechanistic framework for understanding heavier neonates who are born by FET.

Purpose We asked whether the relationship between anti‐Műllerian hormone (AMH) value and the response to ovarian stimulation (OS) might be AMH value‐related and differ for each regimen, aiming at getting clues as to how to choose OS protocols according to AMH levels. We further addressed how AMH value connects with ART outcome. Methods A total of 1112 women undergoing egg retrieval in ART were included. We adopted four OS protocols, that is, clomiphene, clomiphene + low‐dose gonadotropins (Gns), GnRH (Gn‐releasing hormone) + Gns (short), and GnRH antagonist. Results Anti‐Műllerian hormone showed a stronger correlation with egg number compared with age over a wide age range. When patients were stratified into four groups by AMH value (<1, 1‐2, 2‐3, and 3≦ ng/mL), the relationship between AMH and egg number differed among differential OS regimes. The number of eggs rose as AMH and total doses of Gn increased. When analyzed for each AMH group, egg number, but not AMH, was associated with pregnancy rate. Conclusion Different AMH levels exhibit characteristic responses to distinct OS regimens. To improve ART outcomes, personalized OS should be selected so as to maximize egg number, which seems to be a more precise variable than AMH for predicting pregnancy.

Purpose To evaluate the efficacy of an oral gonadotropin‐releasing hormone antagonist (GnRH Ant), relugolix (R), for assisted reproductive technology (ART). Methods We enrolled women undergoing ART using a GnRH Ant for controlled ovarian stimulation. We compared R; 20 mg/day with cetrorelix acetate (C); 0.125 mg. C was administered to 88 women in 2019, and R to 93 women in 2020. Clinical outcomes associated with ART were assessed in both groups. Results The luteinizing hormone levels on the day of human chorionic gonadotropin injection in the R group (1.26 ± 0.93 IU/L) were significantly lower than those in the C group (2.85 ± 3.02 IU/L). There were no cases in which egg retrieval was canceled in both groups. The total doses of gonadotropins administered were greater in the R group compared with the C group. The number of days of GnRH Ant administration in the R group (1.71 ± 0.57 days) was significantly longer compared with the C group (1.48 ± 0.58 days). The number of oocytes collected, fertilization rates, and pregnancy rates (R; 47.1% vs C; 45.8%) did not differ between the two groups. Conclusion An orally active GnRH Ant, relugolix, when used in controlled ovarian stimulation for ART, showed comparable clinical outcomes with cetrorelix.

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