Neurodevelopmental Outcomes in the Offspring of Women with Vitamin D Deficiency and Women Who Received Vitamin D Supplementation During Pregnancy

Vitamin D is an essential nutrient, involved in various biological processes including calcium homeostasis, bone health, immune function, and brain development. Vitamin D from the mother crosses the placenta during pregnancy, directly impacting the neurodevelopment of the fetus. Vitamin D insufficiency is a substantial global health problem, influencing almost 47.9% of individuals, with especially high predominance rates among pregnant women. Background/Objectives: Preclinical studies suggest that maternal vitamin D deficiency results in significant alterations in the development of the offspring’s brain. Nonetheless, randomized clinical trials in humans have produced conflicting results on the beneficial effect of high-dose vitamin D supplementation during pregnancy on neurodevelopmental outcomes. This review aims to evaluate the association of maternal prenatal vitamin D levels and vitamin D supplementation during pregnancy with offspring neurodevelopment. Methods: This study thoroughly reviewed the literature and searched throughout PubMed, ScienceDirect, Cochrane Library, and Google Scholar, adhering to PRISMA guidelines. Studies assessing maternal vitamin D levels, supplementation, and offspring neurodevelopmental outcomes were included based on predefined eligibility criteria. Results: Among 9686 screened studies, only 20 met the inclusion criteria, representing 18,283 mother–child pairs. A small, non-significant trend suggested a positive association between higher maternal vitamin D levels and offspring cognitive, language, motor, and social-emotional development. The strongest associations were observed in cognitive performance and language acquisition, though inconsistencies emerged across studies. Cord blood vitamin D levels showed no consistent effects on neurodevelopment. Maternal vitamin D supplementation during pregnancy demonstrated no reliable benefits for offspring neurodevelopment, with results varying by study design and participant characteristics. Conclusions: Large-scale, multicenter randomized trials, with standardized neurodevelopmental assessments at multiple ages are needed to define the effects of vitamin D deficiency and supplementation during pregnancy on offspring neurodevelopmental outcomes. Future research should investigate the confounding factors contributing to inconsistencies, including supplementation protocols, genetic variations, and assessment methodologies. Clarifying these aspects will enhance the understanding of maternal vitamin D’s role in fetal neurodevelopment and aid in refining prenatal supplementation guidelines.