[Coordination of follicle antrum: from luteal estradiol to the premenstrual antagonist].

The foremost objective of controlled ovarian hyperstimulation (COH) is to ensure the adequate functional and morphologic maturation of early antral follicles to increase the number of viable oocytes and the probability of conception. One of the key points of such a procedure is the achievement of adequate synchronization of follicular growth so that ovulation can be triggered when most follicles have reached concomitant maturation. However, to obtain a good follicular coordination during COH, the physiological heterogeneity of selectable follicles observed during the early follicular phase should probably be overcome. Luteal E2 administration reduces size discrepancies of early antral follicles during the early follicular phase. This approach constitutes a simple and promising method to foster follicular growth synchronization during COH. Luteal GnRH antagonist reduces the mean antral follicle size and reduces heterogeneity of selectable follicles. If these results are confirmed, the luteal administration of E2 or GnRH antagonists represents a potential, more physiological alternative to GnRH agonist or oral contraceptive pretreatment.