Can vitamin D supplementation during pregnancy improve offspring health?

Vitamin D is a fat-soluble nutrient and prohormone. It plays a critical role in bone formation, calcium metabolism, and also has an impact on immune function. As you can see in Figure 1, vitamin D levels are often low during pregnancy^[1][2]. Studies of vitamin D status in pregnant women have shown that low vitamin D levels can influence bone development in utero^[3] in the 19th week, and given the critical role of vitamin D in many features of growth development, it has been hypothesized that low levels of vitamin D might impact overall fetal health during pregnancy.

Previous randomized controlled trials have examined the role of vitamin D supplementation on maternal^[4], neonatal, and infant outcomes^[5]. These studies yielded equivocal results, with inconsistent findings and methodologies across studies. As low vitamin D levels are reported at high levels in the maternal population, it is critical that a robust understanding of how vitamin D supplementation impacts fetal and neonatal development and growth is developed. The purpose of the present study was to assess the full body of literature and paint a clear picture of the effects of vitamin D supplementation during pregnancy on offspring growth, morbidity, and mortality through a systematic review and meta-analysis of randomized controlled trials.

Vitamin D plays a critical role in growth in utero, yet deficiency occurs at high rates in pregnant women, worldwide. Randomized controlled trials examining the effect of vitamin D on offspring growth, morbidity, and mortality have yielded conflicting results. The study under review is a systematic review and meta-analysis of these randomized controlled trials aimed at examining the effect of vitamin D supplementation during pregnancy on offspring growth, morbidity, and mortality.