Vitamin D status during pregnancy: time for a more unified approach beyond borders?

Maternal hypovitaminosis D during pregnancy has been associated with a plethora of adverse health effects on the offspring. Maternal vitamin D status during pregnancy is affected by local climatic conditions. The aim of this article was to report on difficulties related to the heterogeneity of studies available in current literature on vitamin D status during pregnancy and discuss the incorporation of geophysical data in future studies, in an attempt to optimize their design and facilitate their interpretation. We focused on current vitamin D trials during pregnancy and their association with local regional climatic condition in geographical regions such as the Mediterranean basin based on our perspective on the field. Conduction of studies from areas with similar geophysical conditions is necessary, in order to extend our knowledge with respect to the question of which populations and under which circumstances would benefit most from vitamin D supplementation. Future vitamin D studies could benefit from the adoption of a unified concept minimizing these variations by selecting populations residing in areas with similar geophysical conditions adjusting also for their social and dietary habits.