Prenatal vitamins tied to decreased autism odds in some children

  • Schmidt RJ & al.
  • JAMA Psychiatry
  • 27 Feb 2019

  • curated by Emily Willingham, PhD
  • Clinical Essentials
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Takeaway

  • 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.

Key results

  • 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.

Study design

  • Prospective cohort study, 241 younger siblings of autistic children.
  • Outcome: autism diagnosis, nontypical development.
  • Funding: Allen Foundation, MIND Institute, NIH.

Limitations

  • Small numbers not taking prenatal vitamins.
  • Residual confounding likely.