Public health benefits of hair-mercury analysis and dietary advice in lowering methylmercury exposure in pregnant women

Abstract

Aim: To evaluate whether a public health intervention using focused dietary advice combined with a hair-mercury analysis can lower neurotoxic methylmercury exposure among pregnant women, without decreasing overall seafood intake. Methods: At the antenatal clinic at a Danish university hospital, a total of 146 pregnant women were consecutively recruited at the initial ultrasound scan. Dietary advice was provided on avoiding methylmercury exposures from large, predatory fish, and a hair sample from each participant was analysed for mercury, with the results being communicated shortly thereafter to the women. A dietary questionnaire was filled in. Follow-up three months later included a dietary questionnaire and a repeat hair-mercury analysis. Results: In the follow-up group, 22 percent had hair-mercury concentrations above a safe limit of 0.58 µg/g at enrolment, decreasing to 8 percent three months later. Average hair-mercury concentrations decreased by 21 percent. However, total seafood intake remained at the same level after three months. Conclusions: Elevated exposure to methylmercury among pregnant women is an important public health concern in Denmark. The observed lowering of hair-mercury concentrations associated with dietary advice corresponds to a substantial public health benefit that likely makes such intervention highly profitable.