Altered follicular development in clomiphene citrate versus human menopausal gonadotropin-stimulated cycles for in vitro fertilization.

The pattern of periovulatory and luteal phase serum estradiol (E2) and progesterone (P) as well as follicular fluid (FF) E2, P, androgen, gonadotropin, and prolactin concentrations of eight women undergoing clomiphene citrate (CC)/human chorionic gonadotropin (hCG) stimulation and eight women undergoing human menopausal gonadotropin (hMG)/hCG stimulation of follicular development for the purpose of in vitro fertilization were compared. Ovulation was induced with either a 5-day course of CC (100 mg/day beginning on day 5 of the cycle) or an individualized hMG regimen, and laparoscopy was performed 36 hours after hCG administration. The length of the luteal phase was significantly longer (P less than 0.05) in the CC-treated group as compared with the hMG-treated group. The pattern of serum E2 levels differed significantly (P less than 0.01) in that E2 levels were lower in the early and midluteal phase in CC-stimulated cycles; in addition, a delayed second E2 peak was observed in the late luteal phase in these women. Serum P levels, however, were lower in the hMG-stimulated group. Analysis of FF hormone concentrations revealed significantly (P less than 0.05) higher concentrations of E2 and androsterone in the FF of hMG-treated patients. It is concluded that follicular development in CC-stimulated cycles differs markedly from that in hMG-stimulated cycles. These differences may reflect either an altered follicular maturational process or may represent a direct inhibitory effect of CC on follicular steroidogenesis.