Basal and day 12 inhibin concentrations in the prediction of ovarian response to gonadotrophins in women with PCOS

BACKGROUND: In this study, we aimed to investigate whether basal and day 12 serum total inhibin concentrations in women with polycystic ovarian syndro me (PCOS) were of predictive value for the estimation of the ovarian respon se to gonadotrophins. METHODS: Ovulation induction with a very low dose gon adotrophin protocol, starting with 37.5 IU/day, was performed for 40 cycles on 35 patients with PCOS. Day 3 (basal) serum total inhibin, FSH and oestr adiol concentrations; day 12 dominant follicle diameter, inhibin and oestra diol concentrations and midluteal serum progesterone concentrations were me asured during the 40 cycles. The correlations between basal and day 12 inhi bin concentrations and some critical ovulation monitoring parameters were i nvestigated. RESULTS: Ovulation was obtained in 14 out of 40 cycles: 21% of cycles with basal inhibin <1.0 IU/ml; 33.3% of cycles with basal inhibin b etween 1.0-1.9 IU/ml; and 83.3% of those with inhibin concentrations greate r than or equal to2 IU/ml were ovulatory (P < 0.05). Ovulation was achieved in 91.6% of the cycles with a day 12 inhibin concentration greater than or equal to4 IU/ml. CONCLUSIONS: Basal inhibin concentrations may determine p oor and good responders to ovulation induction with very low dose gonadotro phin protocol in patients with PCOS. The day 12 inhibin concentration was f ound to be a more sensitive parameter than the oestradiol concentration in the prediction of follicular maturation.