Vitamin D deficiency increases risk in pregnancy, study finds

Vitamin D deficiency increases the risk of life-threatening pre-eclampsia during pregnancy fivefold, researchers reported Friday.

Some researchers have suspected that low levels of vitamin D contribute to the disorder, characterized by soaring blood pressure and swelling of the hands and feet, but the new study is the first to examine its role directly.

Pre-eclampsia, also known as toxemia, affects up to 7 percent of first pregnancies and can progress to eclampsia, which produces seizures and often fatal complications to the liver, kidneys, lungs, blood and nervous system. Eclampsia causes up to 70 percent of maternal deaths in developing countries.

Epidemiologist Lisa Bodnar and colleagues at the University of Pittsburgh School of Health Sciences identified 15 women who had pre-eclampsia and compared them with 220 who did not.

Although most of the women had levels of vitamin D lower than the optimum 80 nanomoles per liter, those with pre-eclampsia had significantly lower levels. Women whose levels were below 37.5 nanomoles per liter had five times the risk of developing the disorder, the team reported in the Journal of Clinical Endocrinology & Metabolism.

Most of the women were taking prenatal vitamins, which contain 200 to 400 international units (IUs) of vitamin D. "Experts believe you need to take 1,000 IUs per day to make a dent in increasing your levels [of the vitamin]," Bodnar said.