Center for Reproductive Medicine, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China.
Department of Science and Development, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China.
J Int Med Res. 2021 Dec;49(12):3000605211062461. doi: 10.1177/03000605211062461.
This study aimed to compare the clinical outcomes for transfer of Day 3 (D3) double cleavage-stage embryos and Day 5/6 (D5/6) single blastocysts in the frozen embryo transfer (FET) cycle to formulate a more appropriate embryo transplantation strategy.
We retrospectively analyzed 609 FET cycles from 518 women from April 2017 to March 2021. All FETs were assigned to the D3-DET group (transfer of a Day 3 double cleavage-stage embryo), D5-SBT group (transfer of a Day 5 single blastocyst), or D6-SBT group (transfer of a Day 6 single blastocyst). Clinical outcomes were comparatively analyzed.
There were no significant differences in the biochemical pregnancy rate, clinical pregnancy rate, or ongoing pregnancy rate between the D3-DET and D5-SBT groups, but these rates in the two groups were all significantly higher compared with those in the D6-SBT group. The implantation rate in the D5-SBT group was significantly higher than that in the D3-DET group. The twin pregnancy rate in the D5-SBT and D6-SBT groups was significantly lower than that in the D3-DET group.
This study suggests that D5-SBT is the preferred option for transplantation. D6-SBT reduces the pregnancy rate, making it a more cautious choice for transfer of such embryos.
本研究旨在比较冻融胚胎移植（FET）周期中第 3 天（D3）双卵裂期胚胎和第 5/6 天（D5/6）单个囊胚的临床结局，以制定更合适的胚胎移植策略。
我们回顾性分析了 2017 年 4 月至 2021 年 3 月 518 名女性的 609 个 FET 周期。所有 FET 均被分配到 D3-DET 组（移植第 3 天的双卵裂期胚胎）、D5-SBT 组（移植第 5 天的单个囊胚）或 D6-SBT 组（移植第 6 天的单个囊胚）。比较分析临床结局。
D3-DET 组和 D5-SBT 组的生化妊娠率、临床妊娠率和持续妊娠率无显著差异，但均显著高于 D6-SBT 组。D5-SBT 组的着床率显著高于 D3-DET 组。D5-SBT 和 D6-SBT 组的双胎妊娠率显著低于 D3-DET 组。
本研究表明，D5-SBT 是首选的移植方案。D6-SBT 降低了妊娠率，因此对于此类胚胎的转移是一种更谨慎的选择。
