Research paper
Relationship between maternal folic acid supplementation during pregnancy and risk of childhood asthma: Systematic review and dose-response meta-analysis
Study answer
What this study found
Maternal folic acid supplementation during pregnancy was associated with a modestly higher risk of childhood asthma. Across included studies, the pooled OR was 1.07 (95% CI 1.04-1.11); the association was also present for first trimester exposure (OR 1.09, 95% CI 1.05-1.12), third trimester exposure (OR 1.15, 95% CI 1.04-1.26), and whole-pregnancy exposure (OR 1.13, 95% CI 1.10-1.16). Dose-response analysis suggested no association below 581 µg/day, but increased risk at 581 µg/day or more. The association persisted in high- and middle-income economies.
- Study & population
- Systematic review and dose-response meta-analysis of 18 observational studies (13 cohort, 5 case-control) in pregnant women and their children from Europe, North America, Asia, and Australia.
- Intervention
- Maternal folic acid supplementation during pregnancy was evaluated, with contributing cohorts commonly reporting 400 µg/day taken daily; exposure was assessed by trimester and across the whole pregnancy.
- Key limitation
- The evidence was observational, so residual confounding and other biases cannot be excluded.
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Open PDFOriginal abstract
Growing evidence suggests that maternal folic acid supplementation during pregnancy may be associated with the risk of childhood asthma, but these findings remain controversial. Therefore, the purpose of this systematic review and meta-analysis was t…