Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Liwan District, Guangzhou, China.
Reprod Health. 2021 Sep 9;18(1):181. doi: 10.1186/s12978-021-01229-1.
There remains a lack of evidence to demonstrate whether the initiation time of estrogen stimulation is flexible in the proliferative endometrial phase during the artificial cycle for frozen-thawed embryo transfer (AC-FET).
FET records were retrospectively reviewed from a large university-affiliated reproductive medicine center. Only the patients who were undergoing their first embryo transfer with a single blastocyst in the AC-FET cycles were included: thereby 660 cycles were recruited, and the patients were grouped according to their day of estrogen usage initiation as early initiation group (estrogen stimulation initiated during days 2-5 of menses, n = 128) and the late initiation group (estrogen stimulation initiated on or after the 6th day of menses, n = 532). The primary outcome was the ongoing pregnancy rates (OPR).
The rates of biochemical and clinical pregnancies were significantly higher in the late initiation group relative to those in the early initiation group, however, no significant differences were noted between the two groups for OPR. Furthermore, after adjusting for the results of the potential confounders, no impact was observed in the initiation time of estrogen stimulation on the OPR.
This study provides evidence that initiating the estrogen stimulation on after days 2-5 of menses do not exert adverse effects on the OPR in AC-FETs. Thus, AC-FET can be scheduled in a flexible manner without compromising on the pregnancy outcomes.
在冻融胚胎移植（FET）的人工周期中，增殖期子宫内膜阶段雌激素刺激的起始时间是否具有灵活性，目前仍缺乏证据。
本研究回顾性分析了一家大型大学附属医院生殖医学中心的 FET 记录。仅纳入首次接受 FET 且仅移植 1 个囊胚的患者：共纳入 660 个周期，根据雌激素起始使用日将患者分为早起始组（月经第 2-5 天开始雌激素刺激，n=128）和晚起始组（月经第 6 天或以后开始雌激素刺激，n=532）。主要结局是持续妊娠率（ongoing pregnancy rate，OPR）。
晚起始组的生化妊娠率和临床妊娠率显著高于早起始组，但两组的 OPR 无显著差异。此外，调整潜在混杂因素的结果后，雌激素刺激的起始时间对 OPR 没有影响。
本研究表明，在月经第 2-5 天之后开始雌激素刺激不会对 FET 的 OPR 产生不利影响。因此，可以灵活安排 FET，而不会影响妊娠结局。
