Vitamin D in pregnancy and offspring health

The prevalence of vitamin D insufficiency is increasing in western societies. The major source of vitamin D in healthy individuals of normal mobility is through the action of sunlight on the skin, but increased skin pigmentation or behaviours that reduce sun exposure, such as increased time spent indoors or extensive skin covering while outdoors, predispose to vitamin D insufficiency in the absence of dietary supplementation. Although vitamin D has been classically associated with bone mineralization, the wide distribution of vitamin D receptors provides the basis for a more extensive role for vitamin D. Thus, there is accumulating evidence for an involvement of vitamin D in the regulation of cell proliferation and differentiation, brain development, immune responses, the renin-angiotensin system and cardiovascular function. A recent disturbing recognition of startlingly low vitamin D levels amongst women of reproductive age, and indeed, in pregnant women, places in sharp focus our scant understanding of the ramifications of this on offspring health, not only in the immediate neonatal period but, as a result of the recent spotlight on the early origins of adult disease and syndrome X, on the long term outcomes of maternal vitamin D insufficiency.