Exposure to Metals during pregnancy tied to preterm birth, low birth weight babies

They found that metals can act as endocrine disruptors by altering prenatal hormone concentrations during pregnancy. This disruption may depend on when in the pregnancy the mother was exposed.

Prenatal exposure to metals can have enormous consequences even beyond health at birth. Alterations in sex-steroid hormones during pregnancy have been associated with inadequate fetal growth, which leads to low birthweight. Birth size is strongly associated with a child's growth and risk of chronic diseases, including obesity and breast cancer.

"Puerto Rico has one of the highest rates of Superfund sites of any of the U.S. jurisdictions with 18 active sites, which can contribute to the higher rates of exposure to toxic metals," said Rivera-Núnez.

Among pregnant women, metal exposure is higher in those living in Puerto Rico than in those in the continental United States.

"This is important because, compared to the U.S. overall, women in Puerto Rico have significantly higher rates of preterm birth [nearly 12 percent] and other adverse birth outcomes. Additionally, exposure to environmental pollution is exacerbated by extreme weather events, such as hurricanes, droughts and flooding, which may result in elevated exposures to Superfund sites," she added.

According to the study authors, future research should investigate how changes in markers of endocrine function affect birth and other health outcomes. Future studies also should look at essential metals in relation to maternal and fetal health, and metals as mixtures in relation to markers of endocrine function.