Initial observational studies and a systematic review published 5 years ago have suggested that obstetric and perinatal outcomes are better in offspring conceived following frozen rather than fresh embryo transfers, with reduced risks of preterm birth, small for gestational age, low birth weight and pre-eclampsia. More recent primary studies are beginning to challenge some of these findings. We therefore conducted an updated systematic review and cumulative meta-analysis to examine if these results have remained consistent over time.

中文翻译：

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冷冻胚胎移植对母亲和婴儿是否更好？累积荟萃分析能否提供明确的答案？

最初的观察性研究和5年之前发表的系统评价表明，冷冻和新鲜胚胎移植后的后代在产科和围产期结局方面要好，早产风险降低，胎龄低，出生体重低和先兆子痫的发生率降低。最近的基础研究开始挑战其中一些发现。因此，我们进行了更新的系统评价和累积荟萃分析，以检查这些结果是否随着时间的推移保持一致。