Arsenic Exposure May Pose Risks to Unborn Babies

Arsenic exposure in the womb linked to obesity, early puberty in female mice

Arsenic is a naturally occurring chemical found in the earth’s crust that is known to be toxic to humans in high doses. But it may be harmful in low doses as well.

A new study from the National Institutes of Health (NIH) found that female mice exposed in the womb to low levels of arsenic may begin puberty early and become obese as adults.

This finding is significant because the levels of arsenic that the mice were exposed to is equal to 10 parts per billion — the US Environmental Protection Agency’s (EPA) maximum amount of arsenic allowed in drinking water.

Research is still needed to determine whether low-level arsenic exposure in human drinking water could produce the same effects.

"We unexpectedly found that exposure to arsenic before birth had a profound effect on onset of puberty and incidence of obesity later in life," said study co-author Humphrey Yao, PhD, a reproductive biologist at the National Institute of Environmental Health Sciences, in a press release. "Although these mice were exposed to arsenic only during fetal life, the impacts lingered through adulthood."

Dr. Yao and team exposed one group of mice to low levels (10 parts per billion) of arsenic via their drinking water. Another group was exposed to higher levels (42.5 parts per million) — a dose known to have negative effects on mice. These groups were then compared to a third control group.

The mice were exposed to the arsenic in their gestation period, which Dr. Yao and team said corresponds to a human female’s first trimester.

Both male and female mice who were exposed to arsenic, regardless of the level, gained more weight as they aged than the control group. Female mice also experienced an earlier onset of puberty.

This study was published online Aug. 26 in the journal Environmental Health Perspectives.

The National Institutes of Health funded this research. No conflicts of interest were disclosed.