BACKGROUND AND PURPOSE:

• Previous research on prenatal vitamins/ folic acid supplementation and associated reduction in autism spectrum disorder (ASD) risk has been inconsistent
  • There is no data on whether there is impact of vitamins on recurrence in high-risk families
• Schmidt et al (JAMA Psychiatry 2019) sought to assess the relationship between maternal prenatal vitamin use and ASD risk in younger siblings of children with ASD

METHODS:

• Prospective cohort study
  • Data from children and their mothers enrolled in the MARBLES (Markers of Autism Risk in Babies: Learning Early Signs) study
• For this study, the younger siblings were assessed for ASD, via clinical assessments, with the final assessment within 6 month of their third birthday
• Prenatal maternal vitamin use was reported by mothers during telephone interviews
• Outcomes assessed included (defined by Autism Diagnostic Observation Schedule and Mullen Scales of Early Learning subscale scores)
  • ASD
  • Other non-typical development (non-TD)
  • Typical development (TD)

RESULTS:

• 241 younger siblings were included
  • 58.1% male and 41.9% female
  • Average age of 36.5 months
• 95.9% of mothers took vitamins during pregnancy
  • Only 36.1% took prenatal vitamins in the 6 months before pregnancy

Vitamin Use in the First Month of Pregnancy

Comparing children of mothers who took prenatal vitamins vs mothers who did not

• The prevalence of ASD was lower
  • 14.1% vs 32.7%
  • Adjusted relative risk (RR) 0.50 (95% CI, 0.30-0.81)
• Autism symptom severity was lower
  • Adjusted estimated difference –0.60 (95% CI, –0.97 to –0.23)
• Cognitive scores
  • adjusted estimated difference 7.1 (95% CI, 1.2-13.1)
• This effect was not seen for non-TD
  • adjusted RR 1.14 (95% CI, 0.75-1.75)

CONCLUSION:

• ASD recurrence in siblings of children with ASD in high-risk families may be reduced by maternal prenatal vitamin intake during the first trimester
• To inform guidelines, more research is needed to
  • Replicate findings
  • Identify dose thresholds of contributing nutrients and underlying biological mechanisms  

Learn more – Primary Sources:

Association of Maternal Prenatal Vitamin Use With Risk for Autism Spectrum Disorder Recurrence in Young Siblings

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