Richard J Paulson1. 1. Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA. RPaulson@USC.edu
Abstract
OBJECTIVE: To review and synthesize information from the scientific literature pertaining to the hormonal induction of endometrial receptivity before ET. DESIGN: Critical review of selected scientific literature, synthesis and formulation of opinion. SETTING: Not applicable. PATIENT(S): Prospective recipients of oocyte donation or candidates for frozen embryo transfer. INTERVENTION(S): Hormonal treatment for the purpose of induction of endometrial receptivity. MAIN OUTCOME MEASURE(S): Successful induction of endometrial receptivity, as substantiated by live birth rates, pregnancy rates, implantation rates or by measuring putative markers of endometrial receptivity. RESULT(S): The practice of assisted reproductive technology, particularly third-party parenting, in which the source of oocytes is separated from the endometrium, has allowed a separate assessment of embryo and endometrial development. Endometrial receptivity can be induced by exogenously administered E(2) and P in a variety of regimens. The degree of synchrony between embryo and endometrium influences the probability of embryo implantation and may be controlled by initiating P stimulation at different times relative to the stage of embryo development. Many substances have been investigated as adjuncts to E(2) and P in the induction of endometrial receptivity, but at the present time, their value is unproven. CONCLUSION(S): Estrogen and P are the only hormones necessary to prepare the endometrium for implantation.
OBJECTIVE: To review and synthesize information from the scientific literature pertaining to the hormonal induction of endometrial receptivity before ET. DESIGN: Critical review of selected scientific literature, synthesis and formulation of opinion. SETTING: Not applicable. PATIENT(S): Prospective recipients of oocyte donation or candidates for frozen embryo transfer. INTERVENTION(S): Hormonal treatment for the purpose of induction of endometrial receptivity. MAIN OUTCOME MEASURE(S): Successful induction of endometrial receptivity, as substantiated by live birth rates, pregnancy rates, implantation rates or by measuring putative markers of endometrial receptivity. RESULT(S): The practice of assisted reproductive technology, particularly third-party parenting, in which the source of oocytes is separated from the endometrium, has allowed a separate assessment of embryo and endometrial development. Endometrial receptivity can be induced by exogenously administered E(2) and P in a variety of regimens. The degree of synchrony between embryo and endometrium influences the probability of embryo implantation and may be controlled by initiating P stimulation at different times relative to the stage of embryo development. Many substances have been investigated as adjuncts to E(2) and P in the induction of endometrial receptivity, but at the present time, their value is unproven. CONCLUSION(S): Estrogen and P are the only hormones necessary to prepare the endometrium for implantation.