Programmed versus natural frozen embryo transfer: which is the best nest?

Programmed versus natural frozen embryo transfer: which is the best nest?
For implantation to occur, the endometrium needs to be in a receptive state that closely matches the developmental stage of the embryo. Coordinating the transfer of a frozen embryo is key given the ideal window of implantation (WOI) in the mid-secretory phase is short. The time of maximum uterine receptivity is from post-ovulatory days 6-10 (cycle days 22-24 of an idealized 28-day cycle). During this phase, stromal cells undergo pseudo-decidualization and an epithelial cell-like appearance due to the accumulation of glycogen and lipid droplets.
Source: fertstert.org