Vitamin D deficiency during pregnancy increases the risk of pre-eclampsia, gestational diabetes, preterm birth, and low birthweight. A recent meta-analysis led by Dr. Cristina Palacios, associate professor in the Department of Dietetics and Nutrition, investigated whether the current vitamin D recommendation, which is 200 to 600 international units per day (IU/d), is enough in pregnancy for promoting positive health outcomes. They also evaluated if there are negative health effects when using more than the current upper limit recommendation (4000 IU/d). “It is not clear if very high doses, which have been used in several studies, lead to adverse events.” Dr. Palacios said.
This review compared the effects of 601 IU/d or more versus 600 IU/d or less and 4000 IU/d or more versus 3999 IU/d or less, of vitamin D alone or with any other nutrient on pregnancy and neonatal health outcomes.
“Supplementing pregnant women with more than the current vitamin D recommendation may reduce the risk of gestational diabetes but it doesn’t appear to make a difference in the risk of the other outcomes,” Dr. Palacios said. “Also, providing vitamin D supplementation above the upper limits did not provide any benefits but the adverse events were reported differently in most trials, so it was difficult to evaluate this component. That said, vitamin D supplementation continues to appear to be safe and recommended during pregnancy but the actual levels to reduce risks of the outcomes evaluated are not clear.”Friday Letter Submission, Publish on December 27