Its been well known that exposure to metals during pregnancy is associated with adverse birth outcomes in experimental and epidemiological studies. However, the underlying mechanism(s) are not well understood.
A new study by Rutgers University shows that some metals may disrupt the endocrine system, responsible for regulating our body’s hormones. These disruptions may contribute to children’s later health and disease risk.
According to the study, exposure to metals such as nickel, arsenic, cobalt, and lead may disrupt women’s hormones during pregnancy.
Lead author Zorimar Rivera-Núnez, an assistant professor in the Department of Biostatistics and Epidemiology at the Rutgers School of Public Health, said, “A delicate hormonal balance orchestrates pregnancy from conception to delivery and perturbations of this balance may negatively impact both mother and fetus.”
For the study, scientists analyzed blood, and urine samples from 815 women enrolled in the Puerto Rico Test site for Exploring Contamination Threats (PROTECT) study.
PROTECT is an ongoing prospective birth cohort studying environmental exposures in pregnant women and their children around the northern karst zone, including urban and mountainous rural areas of Puerto Rico.
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 birth weight. Birth size is strongly associated with a child’s development and risk of chronic diseases, including obesity and breast cancer.
Rivera-Núnez said, “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.”
“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.”
According to the study authors, future research should investigate how changes in endocrine function markers affect birth and other health outcomes. Future studies should also look at essential metals to maternal and fetal health and metals as mixtures to endocrine function markers.
- Zorimar Rivera-Núñez et al. Association of biomarkers of exposure to metals and metalloids with maternal hormones in pregnant women from Puerto Rico. DOI: 10.1016/j.envint.2020.106310