Review-Vitamin D and the prevention of preeclampsia: A systematic review.

To identify the effect of Vitamin D in reducing the risk of preeclampsia in pregnant women. The review was conducted from December 2011 to March 2012 at the University of Sheffield. Studies were included from the Medline data base, Web of Science (Web of Knowledge), Ovid database and Google Scholar. Studies were limited to published literature only; published between January 1992 to March 2012. A total of seven studies were selected for this review based on the inclusion criteria. One was non-randomized clinical trial, three were cohort studies and three were nested case-control studies. The clinical trial showed a positive association between Vitamin D supplements and the reduction of preeclampsia risk in pregnant women. In addition, one large cohort and two nested case-control studies also showed a protective effect of vitamin D in preventing the risk of preeclampsia. However, the other two cohort studies and a nested case-control study could not find any association between vitamin D levels and the risk of preeclampsia in pregnant women. The studies included in this review show conflicting results about the association of vitamin D levels and the risk of preeclampsia. However, in this review more than half of the studies showed a positive link between Vitamin D deficiencies and Preeclampsia. There is a clear need for further trials and other robust studies to identify the effect of Vitamin D on preeclampsia.