Understanding the relationship between hormones and endometrial receptivity. The egg donation model

Comparative studies between women undergoing standard in vitro fertilization and recipients in whom donated embryos are transferred demonstrate striking differences in embryo implantation and ongoing pregnancy rates. Such characterizations imply that methods currently utilized for prescribed controlled ovarian hyperstimulation result in detrimental effects upon the endometrial environment. Endometrial receptivity to implantation appears to be unaffected by aging, at least through the sixth decade of life, in women properly prepared for embryo transfer using exogenously administered sex steroid. Although decreasing fertility inevitably occurs with time, this drop in success is determined by the aging ovary and should not be considered a uterine event.