Pregnancy is associated with an increased risk of vitamin D deficiency beyond that of the general population. The aim of the current analysis was to synthesize the current evidence on the dose-outcome relationship of vitamin D/serum 25 hydroxyvitamin D (25-OHD) and complications during pregnancy. An additional aim was to estimate the economic burden attributable to inadequate levels of serum 25-OHD. Published literature on the effects of vitamin D supplementation/serum 25-OHD on pregnancy complications, including randomized control trials and non-interventional studies, was searched in bibliographic databases including Pubmed, Google Scholar, Scopus and EMBASE. A positive and significant treatment effect was obtained for pre-eclampsia (OR = 0.75 95% CI 0.662-0.843), but not for preterm birth (OR = 0.783, 95% CI 0.49-1.251) or small for gestational age (OR = 0.76 95% CI 0.38-1.28). Inadequate vitamin D accounted for 14.04% of risk for pre-eclampsia. It is estimated that addressing vitamin D inadequacy in pregnant women in England and Wales would reduce the number of cases of pre-eclampsia by 4126; and would result in a net saving of £18.6 million for the NHS in England and Wales. The current results suggest that based on current evidence a public health policy preventing vitamin D inadequacy in pregnant women is likely to have a positive impact on the NHS budget in England and Wales. This is contingent upon further evidence regarding the vitamin D dose-pregnancy outcome relationship becoming available.
Keywords: 25-hydroxyvitamin D; gestational diabetes mellitus; preeclampsia; pregnancy outcomes; preterm birth; small for gestational age; vitamin D deficiency; vitamin D supplementation.