Preliminary study of blood methylmercury effects on reproductive hormones and relevant factors among infertile and pregnant women in Taiwan

Methylmercury (MeHg) is the most poisonous mercury species and an endocrine-disrupting chemical that could cause reproductive and developmental harm effects in animals. In this study, we recruited 310 infertile women and 57 pregnant women and investigated their blood MeHg levels. The distribution of blood reproductive hormone, selenium and zinc levels, and the difference of relevant factors by the reference level of blood MeHg (5.8 μg/L) of infertile women were further examined. Results showed that greater percentages of sashimi consumption, frequencies of Chinese herbal medicine use, alcohol consumption, and lack of physical activity were observed in infertile women than those for pregnant women. Blood MeHg concentration was significantly greater in infertile than that in pregnant women. Significant concentration differences for FSH and LH by the dichotomized reference level of blood MeHg (5.8 μg/L) in infertile women were not observed, which may stem from that these reproductive hormones in participated infertile women were mostly in the normal reference range. Consumption of fish and sashimi represented the major source of MeHg exposure in infertile women. MeHg levels were elevated in infertile women, and consistent with fish consumption frequency. Compared to the referent level of blood MeHg levels <5.8 μg/L, the elevated blood MeHg levels (⩾5.8 μg/L) in infertile women were 3.35 and 4.42 folds risk in categorized frequencies of fish consumption 1-2 meals per week and more than 3 meals per week, respectively. The obtained results provide evidences and help updating the advisory of fish consumption and improving women's reproductive health.