Abstract

PIP: Literature on the hormonal control of ovoimplantation is reviewed. Areas reviewed include the timing of events of early pregnancy and the initiation of ovoimplantation, the role of ovarian hormones in implantation and the hypothalamohypophyseal regulation of implantation, the morphological and metabolic effects of ovarian hormones on the relationships between the ovum and endometrium, lysis of the zona pellucida, the effects of ovarian hormones on changes in endometrial receptivity and the conditioning of the endometrium by these hormones, the recognition of ovarian hormones by endometrial cells and cell transcriptional events, and the mechanisms of the repression and activation of the blastocyst.