- If mothers of autistic children take prenatal vitamins during the first month of their next pregnancy, the younger sibling has somewhat reduced odds for autism.
- These children do not have reduced odds of a nontypical developmental outcome at 36 months, however.
Why this matters
- Recommendations already emphasize taking prenatal vitamins for most women, including folic acid supplementation preconception for neurodevelopment.
- 95.9% of the mothers reported taking prenatal vitamins during pregnancy.
- Autism prevalence among children of mothers who did not take prenatals in the first month: 32.7%.
- Prevalence among those whose mothers did: 14.1%.
- Adjusted relative risk (aRR) for autism diagnosis if the mother took prenatals in the first month of pregnancy:
- 0.50; 95% CI, 0.30-0.81.
- They were as likely to have an outcome associated with nontypical development at 36 months:
- aRR, 1.14 (95% CI, 0.75-1.75).
- Likewise, maternal folic acid supplementation was associated with decreased likelihood of an autism diagnosis in the child, but not decreased odds for finding nontypical development at age 36 months.
- Prospective cohort study, 241 younger siblings of autistic children.
- Outcome: autism diagnosis, nontypical development.
- Funding: Allen Foundation, MIND Institute, NIH.
- Small numbers not taking prenatal vitamins.
- Residual confounding likely.