Anti-Mullerian hormone levels decline under hormonal suppression: a prospective analysis in fertile women after delivery

Background: AMH's reported stability during periods of hormonal change makes it a practical tool in assessing ovarian reserve. However, AMH declines with age and age-specific cut-offs remain to be established in women with proven fertility. This study aims to determine age-specific ranges of AMH in women with proven fertility. Methods: Two hundred-ten fertile women, aged 18-40 years, were prospectively recruited for AMH measurements within 14 days after delivery and age stratified into 3 groups (18-30, 31-36 and 37-40 years). Eligibility required spontaneous conception within a maximal period of six months. Autoimmune diseases, chemotherapy, radiation, ovarian surgery and polycystic ovary syndrome precluded inclusion. Results: 95% confidence intervals of AMH declined with advancing female age from 0.9-1.1 to 0.6-0.9 and 0.2-0.4 ng/mL (P < 0.001). AMH levels were not statistically associated with day of blood draw after delivery or pregnancy characteristics. Neither were they predictive of resumption of menses. They, however, at all ages were lower than reported in the literature for infertile patients. Conclusions: Like infertile populations, fertile women demonstrate declining AMH with advancing age. Uniformly lower levels than in infertile women suggest that AMH levels do not appear as stable under all hormonal influences as previously reported.