Vitamin D supplementation should be routine in pregnancy: FOR: Recent research supports routine vitamin D supplementation in pregnancy.

Abstract

Today our society worldwide is undergoing some major behavioural changes that have increased the risk of vitamin D deficiency. The risk factors include the risks of skin cancer, the extensive use of sun block, the reduction in exposure to sun light and the failure of the administration of cod liver oil to reduce the incidence of rickets in children, the increasing sedentary lifestyle of children, the apparel choice of certain social groups, and the migration of dark-skinned ethnic groups to northern countries, where sunlight is insufficient for them. There has been recent research to support routine vitamin D supplementation of all women beginning early in pregnancy. Our research group has now completed three longitudinal studies suggesting that vitamin D deficiency is associated with preterm birth, depression during pregnancy and metabolic dysregulation in overweight and obese women during the first year postpartum (Prossner et al. Reprod Sci 2013;20:3; Hobel et al. Reprod Sci 2014;21:3; Pepkowitz et al. PAS 2014, abstract 3545.3). Important findings are that the cord blood levels are consistently 59–61% of the maternal levels (does this increase the risk of the fetus during the first year of life?). With the incidence of vitamin D deficiency (<20 ng/ml) and insufficiency (20–29 ng/ml) during pregnancy ranging 43%–55%, a significant number of newborns are vitamin D deficient at birth. Our findings in the study of obesity suggest that the incidence of vitamin D deficiency and inflammation is very high, indicating that overweight and obese women may have significant metabolic dysregulation and are at significant risk. Hence, our studies have led to a better understanding of what the requirements are during pregnancy to protect the mother and her fetus. We have proposed that the normal level of vitamin D during pregnancy should be at least 40 ng/ml. There are three important recent papers that support our recommendation, which is a life course perspective for women and children. One paper documents an association between maternal higher circulating levels of vitamin D (>30 ng/ml), just above the peak insufficient level, and improved psychomotor development in infants (Morales et al. Pediatrics 2012;130:e913–20). A more recent paper in a randomised, double-blind, placebo-controlled supplementation trial in New Zealand beginning at 27 weeks of gestation (1000 versus 2000 IU for the mothers and 400 versus 800 IU for the child), documented the importance and safety of vitamin D supplementation to significantly increase the proportion of infants with vitamin D levels >20 ng/ml (Grant et al. Pediatrics 2013;133:e143–53). The question remains as to the value and amount (dose) of supplementation beginning in early pregnancy. A recent paper on supplementation with 4000 IU/day in Pakistani women known to be vitamin D deficient found that this regimen was inadequate in achieving normalisation of maternal and neonatal vitamin D status (Hossain et al. J Clin Endocrinol Metab 2014; 99:2448–2455). Finally, to complete the life course perspective, a recent paper confirms the association between all-cause dementia and Alzheimer's disease suggesting that vitamin D supplementation may be important across the life course of individuals (Littlejohns Neurology 2014;83:1–9). The next debate will be whether or not routine vitamin D supplementation in women should begin during the preconception period. None declared.