Low Vitamin D Levels During Pregnancy May Increase Risk of Severe Preeclampsia
PITTSBURGH, Jan. 24, 2014
– Women who are deficient in vitamin D in the first 26 weeks of their pregnancy may be at risk of developing severe preeclampsia, a potentially life-threatening disorder diagnosed by an increase in blood pressure and protein in the urine, according to research by the University of Pittsburgh Graduate School of Public Health
In one of the largest studies to date, researchers studied blood samples collected from 700 pregnant women who later developed preeclampsia in an effort to examine a woman’s vitamin D status during pregnancy and her risk of developing preeclampsia. The full study, funded by the National Institutes of Health
(NIH), is available online in the journal Epidemiology
, and will publish in the March print issue.
“For decades, vitamin D was known as a nutrient that was important only for bone health,” said lead author Lisa Bodnar, Ph.D., M.P.H., R.D
., associate professor in Pitt Public Health’s Department of Epidemiology. “Over the past 10 to 15 years, scientists have learned that vitamin D has diverse functions in the body beyond maintaining the skeleton, including actions that may be important for maintaining a healthy pregnancy.”
Dr. Bodnar and her colleagues also studied blood samples from 3,000 mothers who did not develop preeclampsia. The samples were collected between 1959 and 1965 at 12 U.S. sites enrolled in the Collaborative Perinatal Project. The blood was well-preserved, and researchers were able to test for vitamin D levels decades later.
Scientists controlled for factors that could have affected a woman’s vitamin D status, including race, pre-pregnancy body mass index, number of previous pregnancies, smoking, diet, physical activity and sunlight exposure, which is the body’s primary source of vitamin D.
The researchers found that vitamin D sufficiency was associated with a 40 percent reduction in risk of severe preeclampsia. But there was no relationship between vitamin D and mild preeclampsia. The overall risk of severe preeclampsia in the women sampled was 0.6 percent, regardless of vitamin D status.
“If our results hold true in a modern sample of pregnant women, then further exploring the role of vitamin D in reducing the risk of preeclampsia would be warranted,” said Dr. Bodnar. “Until then, women shouldn’t automatically take vitamin D supplements during pregnancy as a result of these findings.”
Additional co-authors include: Hyagriv N. Simhan, M.D., Janet M. Catov, Ph.D., James M. Roberts, M.D., and Jill C. Diesel, M.P.H., all of the University of Pittsburgh; and Robert W. Platt, Ph.D., of McGill University
This research was supported by NIH grant HD 056999.