Comparison of predictive values of inhibins A and B, and plasma estradiol in IVF patients treated with GnRH agonists and recombinant FSH

The objectives of this study were to determine the mean plasma inhibin A and B kinetics in normoovulatory patients treated by GnRH agonist and rec-FSH and to compare their predictive value with that of plasma estradiol on retrieved oocytes number and pregnancy rate. The study was carried out retrospectively in 36 normoovulatory IVF patients stimulated by GnRH agonist from D21 and rec-FSH from D2 of the following cycle. Two groups of 18 patients (having obtained or not a pregnancy) were paired for age and cause of infertility. Estradiol was measured by direct immunoassay. Inhibin A and B were measured by ELISA (Serotec Limited, Oxford, UK). Inhibin A was correlated with estradiol until P-2 (P0: day of follicles aspiration). Inhibin B rose earlier, its concentration reached its maximum at P-5. Plasma estradiol and inhibin A kinetics were not different among pregnant and nonpregnant women. There was a trend for a broader plasma Inhibin B surface under the curve in pregnant than in nonpregnant women. Estradiol and Inhibin A were correlated to the oocytes number at the end of stimulation (P-2 and D10). Inhibin B was correlated earlier than estradiol and inhibin A, at P-8 and D7. Plasma inhibin A did not demonstrate a better predictive value than estradiol neither of the oocytes number nor the chance of pregnancy. Inhibin B could be useful for early decision of cycle cancellation or stimulation adjustment.