Effects of Elevated Levels of Manganese and Iron in Drinking Water on Birth Outcomes

We examined the impact of elevated exposure levels of pregnant women to manganese and iron through drinking water on pregnancy outcomes. We conducted an epidemiological study among 16,408 pregnant women of Kaunas. We assessed each woman at her residence for exposure to manganese and iron levels measured in four Kaunas public water supply networks. We used a logistic regression to model the association between drinking water quality and birth outcomes controlling the confounding variables. Analysis yielded an increase in adjusted odds ratios (AOR) for term low birth weight (LBW) for moderate exposure level, 1.53 (95% confidence interval (CI) 0.89-2.66); and 1.70 (95% CI 1.07-2.71) for high exposure level. Maternal exposure was associated with a mean reduction of 21 g (SE, 9 g; p=0.02) in birth weight. No associations were observed between manganese and iron levels and preterm birth. These findings suggest that elevated levels of manganese and iron in drinking water are associated with a reduction in birth weight in term-born infants. However, further individual-level epidemiologic studies are necessary to investigate the factors that contribute to the increased sensitivity of some pregnant women.