What is the optimal timing of embryo transfer when there are only one or two embryos at cleavage stage?

Abstract

Today, most IVF programs have moved to blastocyst transfer but there is still uncertainty regarding when to transfer if there are only one or two embryos at the cleavage stage. The aim of this study was to compare the pregnancy rate of day 3 transfers vs. blastocyst stage transfers in patients who had only one or two embryos on day 3. We conducted a retrospective study of 102 patients with one or two cleavage stage embryos that had their embryos transferred on day 3 and 429 patients had their embryos cultured to day 5 for transfer. The number of mature oocytes (4.0 vs 4.6, p = NS) and number of cleavage stage embryos on day 3 was similar in the two groups (1.3 vs. 1.5, p = NS). The clinical pregnancy rate per retrieval (22% vs. 24.6%, p= NS) and the ongoing pregnancy rate per retrieval (20% vs. 20.2%, p = NS) was comparable between the groups. Fifty seven (13.2%) of the patients had cleavage embryo arrest and did not have an embryo to transfer on day 5. We conclude that the cumulative pregnancy rate is the same for patients with 1–2 cleavage stage embryos regardless of whether the embryo is transferred on day 3 or day 5.

摘要

如今, 大多数体外受精项目已经转移到囊胚移植, 但如果卵裂期只有1个或2个胚胎, 何时进行移植仍存在不确定性。本研究的目的是在第3天仅有一个或两个胚胎的患者中, 比较第3天移植与囊胚期移植的妊娠率。我们对102例有1个或2个卵裂期胚胎的患者进行了回顾性研究, 这些患者在第3天接受了胚胎移植, 429例患者的胚胎培养至第5天进行移植。两组第3天成熟卵母细胞的数量（4.0 vs 4.6, p＝NS）和卵裂期胚胎数量相似（1.3 vs. 1.5, p＝NS）。两组之间的每次取出的临床妊娠率（22% vs. 24.6%, p＝NS）和每次取出的持续妊娠率（20% vs. 20.2%, p＝NS）相当。50例（13.2%）患者发生卵裂期胚胎停止发育, 第5天未移植胚胎。我们的结论是, 无论胚胎移植是在第3天还是第5天, 具有1-2个卵裂期胚胎的患者的累积妊娠率相同。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• Cleavage stage
• blastocyst stage
• embryo transfer timing

Disclosure statement

No potential conflict of interest was reported by the authors.