Combined clomiphene citrate (CC) and human menopausal gonadotropins (hMG) in a fixed schedule for follicular recruitment during in vitro fertilization: effects on premature luteinizing hormone (LH) surges.

Recognizing the association between plasma progesterone (P) and an imminent LH surge, we investigated the frequency of P elevation in our stimulation protocol (clomiphene citrate-human menopausal gonadotropins). P was measured retrospectively on the day before, the day of, and the day after human chorionic gonadotropin hCG administration. The means +/- 2 standard deviations for P were as follows: day before hCG, 0.58 +/- 0.86; day of hCG, 0.64 +/- 0.56; and day after hCG, 1.47 +/- 1.22. Seven patients (8%) had P levels greater than 2 SD above the mean. Significant P elevations prior to hCG are infrequent with this protocol, and in the few patients with raised P a trend toward lowered fertilization was noted. The low incidence of P elevation may be secondary to the administration of hCG in a timely manner on the sixth day of estradiol (E2) rise.