Vitamin D deficiency in pregnant women and newborns in Lagos, Nigeria

We aimed to determine the prevalence of Vitamin D deficiency among pregnant women and their newborns in order to make recommendations for Vitamin D supplementation, if necessary. It was a cross-sectional study carried out over a period of 12 months. Information such as use of Vitamin D supplements, number of daytime hours spent outdoors and dressing style was obtained from 166 pregnant women in Lagos, Nigeria; maternal and cord blood 25(OH)D concentration was determined using ELISA. The prevalence of Vitamin D deficiency (<20 ng/mL) in the mothers and newborns was 4.8% and 29.5%, respectively, while insufficiency (21–29 ng/mL) was 28.3% and 46.1%, respectively. Vitamin D supplement use during pregnancy, daytime outdoor exposure and mothers’ dressing style were significantly associated with maternal serum 25(OH)D concentration (p <.05). Our study showed that despite a sunny environment like ours, inadequate serum 25(OH)D concentration is still considerable among pregnant women and their newborns and suggests a need for Vitamin D supplementation in pregnant women.Impact StatementWhat is already known on this subject? Vitamin D is an essential vitamin that plays a major role in maintaining pregnancy and ensuring adequate skeletal formation in the foetus. Studies have shown that there is high Vitamin D deficiency in pregnant women in the temperate regions of the world and thus Vitamin D supplements are being offered to these pregnant women. Studies have also shown that the foetal/neonatal serum Vitamin D level is a reflection of the maternal level. What the results of this study add? The results of this study adds that there may be some factors preventing adequate delivery of Vitamin D from the maternal circulation to the foetal circulation, because despite a low prevalence of Vitamin D deficiency in the mothers, their neonates had a high deficiency rate. What the implications are of these findings for clinical practice and/or further research? The implications of these findings are; further research is warranted in order to find what could be causing a reduced delivery of Vitamin D from the mothers to their foetuses, so as to prevent it if possible. Second, these findings suggest that our pregnant women should still receive a form of Vitamin D supplements, so as to raise their serum Vitamin D to a level which would guarantee optimal foetal concentration.