The importance of the follicular phase to success and failure in in vitro fertilization.

One hundred seventy-five cycles in patients with irreparable tubal disease were stimulated by human menopausal gonadotropin/human chorionic gonadotropin for the purpose of in vitro fertilization. As judged by the height of the peripheral estradiol response, the patients were classified as high, intermediate, or low responders. In addition, the estradiol pattern of the response was found to be separable into six categories. The pregnancy rate was found to be related to the height and to the pattern of peripheral response. The overall pregnancy rate in this consecutive series was 19% but varied according to the height and pattern of response from 40% to 0%.