Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha City, Hunan Province, China.
Reproductive & Genetic Hospital of CITIC-XIANGYA, Changsha City, Hunan Province, China.
PLoS One. 2018 Nov 26;13(11):e0207340. doi: 10.1371/journal.pone.0207340. eCollection 2018.
Frozen-thawed embryo transfer (FET) has become a routine procedure in assisted reproductive technology (ART). In FET, although blastocysts cultured from thawed cleavage-stage embryos are associated with better perinatal outcomes. it may increase cycle cancellation due to no suitable embryo to transfer. The overall clinical outcomes following transfer of thawed cleavage-stage FET and blastocysts cultured from thawed cleavage-stage embryos in young and advanced age patients remains unclear. Therefore, we aimed to identify the optimal FET strategy in young and advanced age women who undergo FET.
This retrospective study included 16,387 thaw cycles. We retrospectively analyzed data of couples who had completed the first FET cycle. Two FET strategies were studied: transfer of thawed cleavage-stage embryos (strategy A) or blastocysts cultured from thawed cleavage-stage embryos (strategy B). The clinical and neonatal outcomes of two FET strategies were compared in young (<35 years) and advanced (≥35 years) age women.
In young women, the clinical outcomes per transfer cycle were better in strategy B than strategy A. While the clinical pregnancy (59.29%, 52.60%) and live birth rates (49.37%, 43.88%) per thaw cycle were significantly higher in strategy A than in B. In women of advanced age, the clinical outcomes per transfer cycle were still better in strategy B than in A, and the clinical pregnancy (36.44%, 39.66%) and live birth rates (25.70%, 30.00%) per thaw cycle were significantly higher in strategy B than in A.
FET of blastocysts cultured from cleavage-stage embryos showed higher efficiency for per transfer cycle whether in younger or advanced age women. Whereas, when cycle cancellations due to no suitable embryo to transfer were considered, cleavage-stage FET was found to be more suitable for younger women, while FET of blastocysts cultured from cleavage-stage embryos was better suited for women of advanced age.
冻融胚胎移植（FET）已成为辅助生殖技术（ART）中的常规程序。在 FET 中，尽管从解冻卵裂期胚胎中培养的囊胚与更好的围产期结局相关，但由于没有合适的胚胎进行移植，可能会增加周期取消率。在年轻和高龄患者中，解冻卵裂期 FET 后和从解冻卵裂期胚胎中培养的囊胚的总体临床结局仍不清楚。因此，我们旨在确定接受 FET 的年轻和高龄女性的最佳 FET 策略。
本回顾性研究纳入了 16387 个解冻周期。我们回顾性分析了完成首次 FET 周期的夫妇的数据。研究了两种 FET 策略：解冻卵裂期胚胎移植（策略 A）或从解冻卵裂期胚胎中培养的囊胚移植（策略 B）。比较了两种 FET 策略在年轻（<35 岁）和高龄（≥35 岁）女性中的临床和新生儿结局。
在年轻女性中，策略 B 的每个移植周期的临床结局优于策略 A。而策略 A 的每个解冻周期的临床妊娠率（59.29%，52.60%）和活产率（49.37%，43.88%）均显著高于策略 B。在高龄女性中，每个移植周期的临床结局仍优于策略 B，策略 B 的每个解冻周期的临床妊娠率（36.44%，39.66%）和活产率（25.70%，30.00%）均显著高于策略 A。
无论在年轻还是高龄女性中，从卵裂期胚胎中培养的囊胚 FET 每移植周期的效率都更高。然而，当考虑由于没有合适的胚胎进行移植而导致的周期取消时，卵裂期 FET 更适合年轻女性，而从卵裂期胚胎中培养的囊胚 FET 则更适合高龄女性。
