Secretion of inhibin B during ovarian stimulation is decreased in infertile women with endometriosis

Objective(s): To determine the levels and pattern of inhibin B secretion du ring ovarian stimulation in patients with endometriosis and to evaluate the correlation between inhibin B levels and variables of follicular and oocyt e development. Design: Retrospective cohort study. Setting: IVF center. Patient(s): Women with endometriosis (n = 20) and tubal factor (n = 10) as the only cause of infertility. Intervention(s): Inhibin B levels were measured during gonadotropin stimula tion on day 1, days 8-11, day of hCG administration, and oocyte retrieval. Main Outcome Measure(s): Patterns and levels of inhibin B secretion were co mpared in the two groups. Other variables analyzed were age, days of gonado tropin stimulation and total ampules used, oocytes retrieved, and the ferti lization and pregnancy rate. Result(s): Inhibin B levels and number of oocytes retrieved were significan tly lower in patients with endometriosis than in the control group. Two pat terns of inhibin B secretion were noted: It peaked in the midfollicular pha se or on the day of hCG administration. In contrast, E-2 levels peaked on t he day of hCG administration. Inhibin B in the midfollicular phase in both groups correlated positively with number of oocytes retrieved. In addition, E-2 and inhibin B levels in the midfollicular phase correlated positively. Conclusion(s): Decreased inhibin B secretion in patients with endometriosis suggests impaired granulosa cell function. Inhibin B may serve as an alter nate marker to assess follicular development or to predict the number of oo cytes retrieved. (Fertil Steril(R) 2000;74:35-40. (C) 2000 by American Soci ety for Reproductive Medicine).