Researchers from the University of Pittsburgh Schools of the Health Sciences said the risk of preeclampsia was present even with supplementation of up to 400 International Units (IU).
Writing in the Journal of Clinical Endocrinology and Metabolism, lead author Lisa M. Bodnar, assistant professor of epidemiology said, "Women who developed preeclampsia had vitamin D concentrations that were significantly lower early in pregnancy compared to women whose pregnancies were normal."
"And even though vitamin D deficiency was common in both groups, the deficiency was more prevalent among those who went on to develop preeclampsia," she added.
Preeclampsia, also known as toxaemia, is marked by soaring blood pressure and swelling of the hands and feet. If the condition worsens, it can lead to seizures, premature delivery, maternal and fetal illness and death worldwide.
According to the Preeclampsia Foundation, the condition affects up to 7 percent of first pregnancies, and health care costs associated with preeclampsia are estimated at 7 billion U.S. dollars a year in the United States alone.
Infants born to mothers with preeclampsia have a risk of mortality five times greater than those born to women with normal pregnancies.
Vitamin D is a fat soluble vitamin that aids in the absorption of calcium, helping the body produce and maintain strong bones. Only a few foods, like egg yolks, fatty fish and cod liver oil, naturally contain vitamin D.
Much of the vitamin D we get comes from fortified foods, such as milk, breakfast cereals, margarine and some brands of orange juice. Another source is sunlight. The skin produces vitamin D when it is exposed to UV-B rays in sunlight.
The National Institutes of Health says fifteen minutes of sunlight a few times a week (without sunscreen to block the UV rays) meets the bodies need for vitamin D.
