Elevated serum thyroid-stimulating hormone is associated with decreased anti-Mullerian hormone in infertile women of reproductive age

Thyroid dysfunction and autoimmune thyroiditis are associated with fertility in women of reproductive age. Anti-Mullerian hormone (AMH), a known biomarker of ovarian function, may be affected by impaired thyroid function; however, the relationship between AMH and thyroid hormone has not been elucidated. In this case-control study, to identify the impact of thyroid hormone on ovarian reserve, we recruited 67 consecutive Japanese infertile patients and 27 normal fertile women aged 30-39 years without impact factors on thyroid and ovarian functions between 2012 and 2013. We assessed patient age, BMI and AMH, prolactin, TSH and FT4 levels of all study participations as independent variables. To evaluate the relationship between AMH and thyroid hormone, we matched patients by age and body mass index as confounding factors using 1:1 matching for statistical analysis of healthy fertile women and infertile patients and obtained 23 pairs. Then, independent variables were subjected to multiple regression analysis. Multiple regression analysis showed that both thyroid-stimulating hormone (TSH) levels and patient age were negatively correlated with AMH levels in infertile patients (patient age and TSH: standardized partial regression coefficient (beta), -0.534 and -0.361; p = 0.003 and 0.036, respectively), but not in normal fertile women. AMH levels were inversely correlated with TSH levels in infertile women of reproductive age.