LAUSR

Objective: The sequential administration of estrogen (E2) and progesterone (P4) administration allows precise manipulation of endometrial growth to prepare for a frozen embryo transfer (FET) cycle. Findings from previous studies on ideal endometrial preparation regimens for FET may be confounded by the fact that they did not control for embryo quality or the number of embryos transferred. The exact limits of endometrial compliance and flexibility with which FETs can be scheduled remains unknown. This study evaluated whether the duration of estradiol supplementation in the follicular phase of an FET cycle impacts clinical outcome.