Maternal and neonatal vitamin D levels and hyperbilirubinemia: A systematic review and meta-analysis

Vitamin D (Vit D) deficiency during pregnancy may have potential adverse effects on the health of mothers and neonates. The relationship between Vit D deficiency and neonatal hyperbilirubinemia is unknown. The aim of this study is to determine the relationship between Vit D levels in mothers and neonates and the occurrence of neonatal hyperbilirubinemia.

This systematic review and meta-analysis were guided by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A literature search was conducted in electronic databases: PubMed, Cochrane, CINAHL, Scopus, Web of Science, Ovid MEDLINE, and MEDLINE Ultimate until the end of 2024 to find studies published in English that investigated Vit D levels in mothers or neonates and their associations with hyperbilirubinemia. The Newcastle Ottawa Scale (NOS) tool was used to assess the quality of the articles included. A random effects model was used for (subgroup) meta-analyses, assessing heterogeneity with I-squared, publication bias with funnel plot, Egger and Begg tests, and conducting meta-regression to explore heterogeneity sources.

Of the 29 studies included in this systematic review, 25 were eligible for meta-analysis. Despite the overall lack of significant results in some aspects of this meta-analysis, the random-effects model showed that Vit D levels were significantly lower during pregnancy in mothers of neonates with hyperbilirubinemia compared to mothers of neonates without hyperbilirubinemia (MD: -7.98 nmol/L, 95%CI: -11.02 to -4.94, I2: 49.82 %, p < 0.001). Additionally, Vit D levels were significantly lower in neonates with hyperbilirubinemia compared to neonates without hyperbilirubinemia (MD: -19.53 nmol/L, 95%CI: -25.42 to -13.64, I2: 93.76 %, p < 0.001).

This review suggests that higher maternal Vit D levels during pregnancy may lead to higher Vit D levels in neonates and ultimately a lower risk of neonatal hyperbilirubinemia.