Programmed oocyte retrieval: clinical and biological effects of oral contraceptives administered before in vitro fertilization.

We have prospectively compared two regimens of suppression of the hypothalamic-pituitary-ovarian axis by oral contraceptives (OCs) for 15 or 30 days and two ovarian stimulation protocols. The latent phase, which represents a period of ovarian insensitivity, was prolonged and directly correlated to the duration of suppression. Thirty days' suppression, compared with 15 days', resulted in the cancellation of more cycles and a lower fertilization and pregnancy percentage. No significant increase in either serum progesterone or luteinizing hormone was noted in suppressed cycles. It is concluded that if programming is desired, OCs should be used for the shortest period possible. The variation in the length of the follicular phase indicates that there is a different 'fixed' day for retrieval for each suppression-stimulation protocol and this day should be established prospectively.