Endometrial preparation for third-party parenting and cryopreserved embryo transfer

Endometrial preparation for third-party parenting and cryopreserved embryo transfer
The advent of third party parenting ushered in the era of artificial stimulation of the endometrium. Initially intended only for patients with ovarian failure, exogenous induction of endometrial receptivity was quickly shown to be as good as natural endometrial preparation, with the advantage that the timing of embryo transfer could be controlled. It is perhaps surprising that even though the ovary produces a variety of steroids, that estradiol (E2) and progesterone (P) alone would be needed to achieve optimal receptivity; no other substance has ever been shown to improve on the basic regimen of E2 and P.
Source: fertstert.org