Arsenic exposure during pregnancy linked to low-birth-weight infants

Oct 15 2007

Bangladeshi women exposed to high levels of arsenic during pregnancy are at increased risk of having a low-birth-weight infant, reports a study in the October Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM).

Led by Dr. Karen L. Huyck of Harvard School of Public Health, the researchers evaluated several measures of arsenic exposure in 52 pregnant women in Bangladesh, average age 24 years. Arsenic exposure at various times during pregnancy was compared with the infants' final birth weight.

Women who had high levels of arsenic measured in hair samples during early pregnancy—around the end of the first trimester—were more likely to give birth to a low-birth-weight infant. Higher levels of arsenic measured in the mother's hair and drinking water during pregnancy were related to higher levels of arsenic in the infant's hair after birth.

The higher the mother's exposure to arsenic, the lower the infant's birth weight. For each one-microgram increase in the mother's hair arsenic level, birth weight decreased by 194 grams—nearly seven ounces. Mothers at the highest level of contamination had hair arsenic levels of over three micrograms (per gram).

Long-term exposure to arsenic in the environment has many adverse effects on human health. Although previous studies have linked arsenic exposure to low birth weight and other problems of pregnancy and childbirth, most did not use "biomarkers" of individual women's exposure during pregnancy.

Arsenic contamination of drinking water is a problem in many countries around the world—including the United States and some other developed countries. Arsenic contamination may come from industrial or natural sources. In Bangladesh, an estimated 133 million people are at risk of drinking water contaminated with arsenic. The women in the study lived in a rural area with a particularly high level of arsenic contamination.

The results show that high exposure to arsenic during early pregnancy increases the risk of having a low birth weight infant. The experience also demonstrates the feasibility of conducting large-scale prospective studies of reproductive outcomes in rural Bangladesh. The researchers plan further analysis of their data to clarify the relationship between arsenic exposure and pregnancy outcomes, with the goal of developing effective clinical and public health responses to the problem.

http://www.joem.org/