Study finds reducing cadmium exposure during pregnancy may improve birth outcomes

Oct. 6, 2014

Reducing women’s exposure to cadmium during pregnancy likely would cut down on adverse outcomes such as preterm labor, low birth weight and early pregnancy loss, a new University of North Carolina at Chapel Hill study has found.

Dr. Rebecca Fry

In an article published July 30 online in the Journal of Exposure Science and Environmental Epidemiology, Rebecca Fry PhD, associate professor of environmental sciences and engineering at UNC’s Gillings School of Global Public Health, and colleagues found above-average levels of cadmium, a toxic heavy metal, in the blood of pregnant women.

The study, “Cadmium levels in a North Carolina cohort: Identifying risk factors for elevated levels during pregnancy,” reported that while smoking cigarettes accounts for a significant portion of human exposure to cadmium, diet and proximity to industrial works are the other major sources of the metal for non-smokers.

The study found that blood cadmium levels among smokers were twice as high as levels in non-smokers and highlighted the public health issue that very few states in the U.S. perform any sort of prenatal screening for environmental toxicants.

More than 60 percent of the women in the study, which involved women living in Durham County (N.C.) who were receiving prenatal care either at Duke University Obstetrics Clinic or the Durham County Public Health Prenatal Clinic, had an elevated blood cadmium level. Smoking was associated with a 21 percent increase in risk for higher cadmium levels.

In addition to the adverse effects on newborns, chronic exposure to cadmium in adults has been associated with elevated risks for cancer and heart and lung disease.

To this point, very few data are available on cadmium levels among pregnant women. Given the health risks of smoking and cadmium exposure, the study urges more monitoring of exposure to toxic metals during pregnancy.

Non-smokers in the study group also experienced significant cadmium exposure, which emphasizes the need to understand factors that may affect cadmium levels among women without the most common source of exposure to the metal.

Fry’s study points out the need to promote smoking cessation during pregnancy. It also adds some urgency to collecting more data on cadmium exposure during pregnancy from more communities and provides information that can improve understanding of prenatal exposure as a public health issue and assist in the development of prevention programs.

Study co-authors include Sharon Edwards, statistician, Pamela Maxson, PhD, research director, and Marie Lynn Miranda, PhD, dean and professor, of the Children’s Environmental Health Initiative, School of Natural Resources and Environment, University of Michigan at Ann Arbor. Miranda also is professor in the departments of pediatrics and obstetrics and gynecology at University of Michigan.