Association of vitamin D level and vitamin D deficiency with risk of preeclampsia: A systematic review and updated meta-analysis.

OBJECTIVES Because of the immune modulatory effects of vitamin D3 in preeclampsia, we intend to have a systematic review and meta-analysis on association of both 25-hydroxy vitamin D (25-OHD) level (parametric approach) and 25-OHD deficiency (non-parametric approach) with preeclampsia. As well, for the parametric part, we used receiver operating characteristic (ROC) curve model. MATERIALS AND METHODS We used Web of Science, PubMed and Science Direct data bases through searching in titles. Google Scholar search engine was used in order to find missing papers. Finally 23 studies were imported. Both random and fixed models were reported. RESULTS Based on the forest plot, lower levels of 25-OHD were significantly associated with risk of preeclampsia (fixed and random P < 0.001). Based on the forest plot, vitamin D deficiency (25-OHD < 20 ng/ml) was significantly associated with risk of preeclampsia (fixed P < 0.0001; random P = 0.0029; fixed OR = 1.33; random OR = 1.54). Based on ROC curve results, we found 2 cutoffs of 10.60 and 20.05 ng/ml. CONCLUSION Women with vitamin D deficiency at cutoff 20 ng/ml are more at risk of preeclampsia. This association can be specific up to 90% at 10.60 ng/ml cutoff. Treatment of vitamin D deficiency is necessary before pregnancy.