Vitamin D deficiency in early pregnancy and the risk of developing cerebral palsy: A case–control study

Aim To investigate whether maternal deficiency of vitamin D in early pregnancy increases the risk of cerebral palsy (CP) in offspring. Method This registry and biobank‐based case–control study consisted of mother–child pairs from Scania, Sweden. Cases ( n = 322) were identified from a nationwide CP‐register born between 1995 and 2014. Random population controls ( n = 343) and preterm controls ( n = 258) were identified from a birth registry. Serum samples taken during pregnancy were obtained from a biobank and 25(OH)D 3 concentrations were categorized into three groups: sufficient (≥ 75 nmol/L), insufficient (50–74.9 nmol/L), and deficient (< 50 nmol/L). Logistic regression was used to investigate associations between 25(OH)D 3 concentrations and CP. Separate analyses were completed among children born preterm and at term, as well as for subtypes of CP. Results Deficiency of 25(OH)D 3 was not associated with a significantly higher risk of CP compared with sufficient values in the studied groups of all children (odds ratio [OR]: 1.34; 95% confidence interval [CI]: 0.86–2.10), children born at term (OR: 1.48; 95% CI: 0.89–2.44), and children born preterm (OR: 0.74; 95% CI: 0.37–1.46). Interpretation No apparent association between 25(OH)D 3 and CP was observed; however, the relatively small sample size and reliance on a single vitamin D measurement may have limited the detection of modest effects.