Does Vitamin D During Pregnancy Improve Birth Outcomes?
(HealthDay News) — Prenatal vitamin D supplementation during pregnancy may have some benefits, although the evidence is low quality, according to research published online Nov. 29 in The BMJ.
Daniel E. Roth, M.D., Ph.D., from the University of Toronto, and colleagues conducted a systematic review and meta-analysis of trials to estimate the effects of vitamin D supplementation during pregnancy on 11 maternal and 27 neonatal/infant outcomes. Data from 43 trials with 8,406 participants were eligible for meta-analyses.
The researchers found that vitamin D increased maternal/cord serum concentration of 25-hydroxyvitamin D, with a weak dose-response effect. Maternal clinical outcomes were rarely determined or reported, and no evidence of benefits was seen with available data. The mean birth weight was increased with vitamin D, and there was a reduction in the risk for small-for-gestational-age births (risk ratio, 0.60; 95 percent confidence interval, 0.40 to 0.90), but in sensitivity and subgroup analyses the findings were not robust. Vitamin D supplementation had no impact on preterm birth (risk ratio, 1.0; 95 percent confidence interval, 0.77 to 1.30). Strong evidence was found for prenatal vitamin D reducing the risk of wheeze in offspring by age 3 years (risk ratio, 0.81; 95 percent confidence interval, 0.67 to 0.98). An overall low risk of bias was seen in eight of 43 trials.
"The evidence to date seems insufficient to guide clinical or policy recommendations," the authors write.