Vitamin D and its impact on maternal-fetal outcomes in pregnancy: A critical review

Abstract

The role of vitamin D beyond its classical function in calcium homeostasis has been of significant interest in recent years. There has been expanding research on the pleiotropic role of vitamin D in pregnancy and the implications of its deficiency on maternal-fetal outcomes. Several studies have associated low maternal vitamin D status to adverse outcomes in pregnancy, including preeclampsia, gestational diabetes, preterm births, low birth weight, and others. Several randomized controlled clinical trials of Vitamin D supplementation during pregnancy have also been conducted. Though some of the studies found improvement in pregnancy outcomes with vitamin D supplementation, others have not shown any association. In this article, we have critically reviewed the observational and interventional studies, published primarily within the past two years (January 2014 to February 2016) on the influence of vitamin D deficiency on pregnancy and the impact of its supplementation. The potential underlying mechanisms of vitamin D in regulating each of the outcomes have also been discussed.

Keywords: Pregnancy; maternal outcomes; neonatal outcomes; vitamin D; vitamin D supplementation.

Figure 1

The schematic diagram depicts the adverse maternal and fetal outcomes associated with vitamin D deficiency.

Figure 2

The sxhematic diagram depicts the activation of vitamin D by two hyroxylation steps, one each in liver and kidney, followed by the normal physiological role of vitamin D in each organ. The specific maternal and fetal repercussion of vitamin D deficiency are mentioned below the dotted line.