Study highlights relationship between prenatal arsenic exposure and adverse health outcomes in newborns

Rebecca Fry, PhD (left) and SRP trainee Jessica Laine.

In a recent study, researchers in Dr. Rebecca Fry’s lab have demonstrated that pregnant women in Gómez Palacio, Mexico are being exposed to potentially harmful levels of inorganic arsenic in their drinking water and highlighted a negative relationship between maternal arsenic metabolite concentrations in urine and adverse health outcomes for the newborn. The paper, Maternal Arsenic Exposure, Arsenic Methylation Efficiency, & Birth Outcomes in the Biomarkers of Exposure to Arsenic (BEAR) Pregnancy Cohort in Mexico, published in the February 2015 issue of Environmental Health Perspectives, was named the Article of the Month in March by the Children’s Environmental Health Network.

This study examined the association of inorganic arsenic exposure during pregnancy and corresponding birth outcomes in the BEAR cohort in Mexico. Exposure to elevated levels of inorganic arsenic in drinking water is a major public health concern, as arsenic has been linked to numerous adverse health outcomes. Some studies indicate that pregnant women exposed to arsenic risk having newborns with low birthweight, preterm birth, and miscarriage. Additionally, individuals exposed to arsenic prenatally or in early childhood are at risk of adverse health effects later in life, including cancer.

The BEAR study sought to understand the effects of prenatal inorganic arsenic exposure and metabolism on the health of the fetus. Researchers assessed the extent of arsenic exposure and monitored the presence of certain arsenic metabolites, which indicate exposure, in the urine of 200 pregnant women from the Gómez Palacio area in the state of Durango in northern Mexico. Residents in this area are believed to be exposed to levels of inorganic arsenic in drinking water that exceed 50 μg/L, which is 5 times the level recommended in the World Health Organization’s (WHO) drinking water guidelines, and twice as a high as Mexico’s maximum contaminant levels (MCL). Researchers then examined the connection of arsenic metabolites to adverse health outcomes in the newborns.

The study found that concentrations of inorganic arsenic in the women’s drinking water ranged from <0.5 to 236 μg/L, and more than half of the women had drinking water arsenic concentrations that exceeded the WHO’s recommended guideline. The study also found that maternal concentrations of arsenic metabolites in urine were negatively associated with newborn birth weight, length, and gestational age. This means higher levels of arsenic metabolites increased the likelihood that a baby would be born smaller and earlier.

“These data highlight the health risks for infants associated with prenatal exposures to toxic substances and support efforts for increased environmental monitoring,” says Dr. Fry.

The long-term goal of the BEAR study is to continue to examine the effects of environmental exposure to arsenic on the health of women and children in order to provide information to protect individuals from preventable exposure.