Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China; National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China; Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China; Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing, China.
Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, China.
Reprod Biomed Online. 2023 Aug;47(2):103197. doi: 10.1016/j.rbmo.2023.03.008. Epub 2023 Mar 15.
Does the time interval between oocyte retrieval and frozen embryo transfer (FET) affect pregnancy outcomes after a freeze-all strategy?
Retrospective study including a total of 5995 patients who underwent their first FET following a freeze-all cycle between 1 January 2017 and 31 December 2020. Patients were divided into immediate (the interval between oocyte retrieval and the day of first FET ≤40 days), delayed (>40 days but ≤180 days) and overdue groups (>180 days). Pregnancy and neonatal outcomes were analysed, and multivariable regression analysis was used to study the effect of FET timing on the live birth rate (LBR) in the entire cohort and the different subgroups.
The LBR was significantly lower in the overdue group than in the delayed group (34.9% versus 42.8%, P = 0.002); however, after adjusting for confounding factors, the difference was not statistically significant. The immediate group had a comparable LBR (36.9%) to the other two groups in both the crude and adjusted analyses. Multivariable regression analysis showed no impact of FET timing on LBR in the whole cohort or in the subgroups according to ovarian stimulation protocol, trigger type, insemination method, reason for freezing all, FET protocol or transferred embryo stage.
The time interval between oocyte retrieval and FET does not impact reproductive outcomes. Unnecessary delays in FET should be avoided to shorten the time to live birth.
取卵后与冻融胚胎移植（FET）之间的时间间隔是否会影响冷冻所有策略后的妊娠结局？
这是一项回顾性研究，共纳入了 5995 名于 2017 年 1 月 1 日至 2020 年 12 月 31 日期间接受首次 FET 的患者。患者分为即刻组（取卵后与首次 FET 日的时间间隔≤40 天）、延迟组（>40 天但≤180 天）和过期组（>180 天）。分析妊娠和新生儿结局，并采用多变量回归分析研究 FET 时机对整个队列和不同亚组活产率（LBR）的影响。
过期组的 LBR 明显低于延迟组（34.9%比 42.8%，P=0.002）；然而，在调整混杂因素后，差异无统计学意义。即刻组在未调整和调整分析中与其他两组的 LBR 相当（分别为 36.9%）。多变量回归分析显示，FET 时机对整个队列或根据卵巢刺激方案、扳机类型、授精方法、冷冻所有原因、FET 方案或移植胚胎阶段的 LBR 均无影响。
取卵后与 FET 之间的时间间隔不会影响生殖结局。应避免 FET 不必要的延迟，以缩短活产时间。
