Effects of oral contraceptives administered at defined stages of ovarian follicular development

Objective: To elucidate the effects of initiating oral contraceptives (OC) at defined stages-of ovarian follicle development. Design: Prospective longitudinal study. Patient(s): Forty-five healthy women between the ages of 18 and,35 years, randomized to initiate OC when a follicle,diameter of 10, 14, or 18 mm was first detected. Intervention(s): The OC administration at defined stages of dominant follicle development. Main Outcome Measure(S): Fates of all dominant follicles and serum concentrations of E2-17 beta, LH, and P before and after initiating OC. Result(s): No ovulations (0/16) were observed when OC use was initiated at a follicle diameter of 10 mm, 4/14 (29%),follicles ovulated when OC were initiated at 14 mm, and 14/15 (93%) ovulated when OC were, initiated at 118 mm. When ovulation did not occur, follicles regressed or became anovulatory cysts. Peak LH and E-2 levels were lowest in the 10-mm group, moderate in the 14-mm group, and greatest in the 18-mm group. Peak endocrine levels in all treatment groups were lower than the historic reference group. Conclusion(S): Follicular development, ovulation, and endocrine concentrations were not suppressed effectively. when OC were initiated at late stages of dominant follicle development.