Ovarian antibodies, FSH and inhibin B: independent markers associated with unexplained infertility.

Premature menopause and unexplained infertility are associated with ovarian antibodies, a marker of ovarian autoimmunity. In premature menopause, FSH is also elevated while in unexplained infertility FSH concentrations are often normal. The relationship of ovarian antibodies and FSH and inhibin B, as markers of follicle function, was investigated in unexplained infertility. Ovarian antibodies were determined by immunoassay in comparison to normal controls (n = 12); 51.9% were positive at two SD (P < 0.05) and 38.5% were positive at three SD above the control mean (P < 0.01). In this study three SD above the control mean was considered positive. In unexplained infertility, three out of 10 (30%) had elevated day 3 FSH (>10 mIU/ml) and ovarian antibodies, while 17/42 (40%) had normal FSH (<10 mIU/ml) and ovarian antibodies. In women with normal FSH, two out of seven (29%) had low inhibin B concentrations (<33 pg/ml) and ovarian antibodies, and 15/35 (43%) had normal inhibin B concentrations (> 33 pg/ml) and ovarian antibodies. Similarly, when women with and without ovarian antibodies were compared there was no difference in mean FSH or mean inhibin B concentrations. Thus, unlike other endocrine autoimmune disorders, hormone concentrations are not predictors of potential ovarian autoimmunity. This suggests that in unexplained infertility ovarian antibodies are an independent marker of potential ovarian failure, and may precede changes in regulatory hormones.