Natural Cycle Frozen Embryo Transfer: Evaluating Optimal Protocols for Preparation and Timing.

Background: While natural cycle frozen embryo transfer (NC-FET) is becoming increasingly common, significant practice variation exists in the use of ovulation induction medications, administration of ovulation trigger, and timing of embryo transfer without consensus as to the optimal protocol.

Aims: The objective of this study is to evaluate the association of key aspects of the NC-FET protocol with implantation, pregnancy and live birth.

Settings And Design: This was a retrospective cohort study of blastocyst stage NC-FET cycles from October 2019 to July 2021 at a single academic fertility centre.