ENDOMETRIAL RECEPTIVITY IN IN VITRO FERTILIZATION AND EMBRYO TRANSFER (IVF & ET)

Abstract

Endometrial receptivity is a self limiting period in which the endometrial eptithelium acquires a functional and transient ovarian steroid dependent status that allows blastocyst adhesion. A normal human endometrium is controlled by the ovarian sex steroid hormones estrogen and progesterone, which. elicit their actions by binding to specific high- affinity receptors.•

Extensive and successful research efforts have been made to determine when the uterus becomes receptive to embryo and what are the decisive factors that are involved in this intricate process.

The early concept that the endometrium is optimally receptive to implantation only during a defined period seems also to be valid in humans. Although the exact time frame of the so-called "implantation window" still is fuzzy it is well accepted it encampasses the fifth to the seventh days after ovulation • and is surrounded by a • refractory endometrial status.