Abstract：
What is the effect of a single low-dose recombinant hCG injection after embryo transfer (ET) in letrozole-induced modified natural frozen embryo transfer cycles (mNC-FET)?. An observational study was conducted in the university-affiliated referral clinic between 2022 and 2024. Women aged 18-42 with at least one vitrified blastocyst obtained from the previous cycle(s) were included. Ovulation induction for endometrial preparation was initiated with oral letrozol (5 mg/day) for five days. Ovulation was triggered using 6500 IU rec hCG sc when the leading follicle > 17 mm, endometrial thickness > 7.5 mm, and serum progesterone (P) < 1.5 ng/ml. All women received 30 mg dydrogesterone/day po for additional five-day luteal support. On the 6th day, ET was performed. Based on a quasi-randomized design, a group of women additionally received a half single bolus of (3250 IU) rec hCG (sc) on the morning of 3rd day of ET (hCG group). Women who did not receive additional hCG were assigned as controls. One hundred fifty-four women were detected to be eligible for the study among 2150 initiated FET cycles during the period. Demographic data of the groups, including mean women\'s age, BMI, serum AMH, and infertility etiologies, were comparable in terms of variables. Mean serum progesterone values and the number of transferred embryos were also similar. A significantly higher ongoing pregnancy/started cycle was documented in the hCG group than in controls (46.7% vs 33.6% respectively, p = 0.03*). A single low-dose hCG injection after ET may improve the OPRs of women in letrozole mNC-FET cycles.
摘要：
胚胎移植（ET）后单次低剂量重组hCG注射在来曲唑诱导的改良自然冷冻胚胎移植周期（mNC-FET）中的作用是什么？2022年至2024年在大学附属转诊诊所进行了一项观察性研究。包括18-42岁的具有至少一个从先前周期获得的玻璃化胚泡的女性。用口服来曲唑(5mg/天)开始子宫内膜制备的排卵诱导,持续5天。当前导卵泡>17毫米时，使用6500IUrechCGsc触发排卵，子宫内膜厚度>7.5毫米，血清孕酮（P）<1.5ng/ml。所有女性接受30毫克地屈孕酮/天po额外的5天黄体支持。第六天,进行ET。基于准随机设计，一组女性在ET的第3天早晨（hCG组）额外接受了半单次推注（3250IU）rechCG（sc）。没有接受额外hCG的女性被指定为对照。在此期间，在2150个启动的FET周期中，检测到154名妇女符合研究条件。这些群体的人口统计数据，包括平均女性年龄，BMI,血清AMH,和不孕症病因，在变量方面具有可比性。平均血清孕酮值和移植胚胎的数量也相似。hCG组的持续妊娠/开始周期明显高于对照组（分别为46.7％和33.6％，p=0.03*)。ET后单次低剂量hCG注射可能会改善来曲唑mNC-FET周期中女性的OPR。
