Update on vitamin D: More than just a nutrient

An increasing number of pregnancy complications have been ascribed or at least associated with vitamin D deficiency. Vitamin D has undergone a metamorphosis from nutrient to hormone and more recently has been recognised to have broader biological relevance. This includes potential immunogenic, oncogenic and metabolic actions. This review outlines the roles of vitamin D, the problems in accurate measurement and determining normal ranges and how this is important in an understanding of vitamin D in normal and abnormal pregnancy.