Controlled ovarian hyperstimulation (COH) determines an anticipation of endometrial maturation and a premature occurrence of the implantation window, as shown by histological, histochemical, and molecular studies and indirectly by clinical trials. There is growing agreement that in patients hyper-responding to COH and in those undergoing transfer at the blastocyst stage, deferring the transfer in a subsequent frozen cycle could increase pregnancy outcomes. For blastocysts, implantation after a fresh transfer may be limited as the implantation window is already closed while, in hyper-responders to COH, the anticipation magnitude could be more marked thus hampering implantation also for cleavage-stage embryos. Research should focus in depth on pregnancy outcomes and on the most suitable modality to prepare the endometrium for frozen transfers.

中文翻译：

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冷冻试管婴儿周期以规避子宫内膜的荷尔蒙风暴

正如组织学、组织化学和分子研究以及临床试验间接表明的那样，受控卵巢过度刺激 (COH) 决定了子宫内膜成熟的预期和着床窗口的过早发生。越来越多的人一致认为，对于对 COH 反应过度的患者和在囊胚阶段接受移植的患者，在随后的冷冻周期中推迟移植可能会增加妊娠结局。对于囊胚，新移植后的植入可能会受到限制，因为植入窗口已经关闭，而在对 COH 的超反应者中，预期幅度可能更加明显，从而阻碍了卵裂期胚胎的植入。研究应深入关注妊娠结果和最合适的方式来为冷冻移植准备子宫内膜。