Blastocyst vs cleavage‐stage embryo transfer: systematic review and meta‐analysis of reproductive outcomes

Abstract

Objectives (RR, 1.10 (95% CI,12 Correspondence to: Prof. W. P. Martins, SEMEAR Fertilidade, Av Aurea Apparecida Braghetto Machado, 220 Ribeirão Preto -SP, 14021-460 Brazil (e-mail: wpmartins@gmail.com) Accepted: 4 October 2016RCTs, 2418 women, I 2 = 64%), cumulative pregnancy (RR, 0.89 (95% CI,), four RCTs, 524 women, I 2 = 63%) and miscarriage (RR, 1.08 (95% CI,, 10 RCTs, 763 pregnancies, I 2 = 0%). There was moderate-quality evidence of a decrease in the number of women with surplus embryos after the blastocyst-stage embryo transfer (RR, 0.78 (95% CI,

Influence of cryopreservation on perinatal outcome after blastocyst‐ vs cleavage‐stage embryo transfer: systematic review and meta‐analysis

“…Furthermore, extending embryo culture could favor a single embryo transfer policy, which is recommended to ensure live births for infertile couples and to reduce the risk of multiple pregnancies. However, these advantages were recently questioned by Martins et al ,. and we concur with them that more well designed randomized trials are needed before a definitive conclusion can be drawn regarding this issue.…”

“…Despite theoretical advantages, the clinical efficacy of blastocyst‐stage vs cleavage‐stage transfer is debatable. In fact, while in 2016 a Cochrane meta‐analysis reported increased rates of clinical pregnancy and live birth after blastocyst transfer, a more recent meta‐analysis did not find any statistically significant differences in these outcomes between blastocyst‐ and cleavage‐stage transfer.…”

Fresh versus frozen-thawed blastocyst transfer in high responders

“…The reason why only included patients who had undergone blastocyst transfers in our study was to homogenize the study group. Discussions in the literature on the relative effects of blastocyst versus cleavage-stage embryo transfers on the maternal and neonatal outcomes are ongoing, as are discussions on the effects on implantation and pregnancy rates [20][21][22][23].…”

How should we report outcomes in reproductive medicine?

“…Theoretically, if the intervention under study is thought to influence the chances of ongoing pregnancy occurring, but not its course once established, then conclusions based on ongoing pregnancy will be similar to those based on live birth. Since ongoing pregnancy is reported much more often than is live birth, estimates of treatment effect based on ongoing pregnancy usually have much more precision than do estimates based on live birth 25 . Indeed, we have shown previously that conclusions drawn from the endpoints pregnancy and ongoing pregnancy are on average similar to those drawn from the endpoint live birth, albeit with more statistical power 26 .…”