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

Related ObG Topics:

Reduced Risk of Autism in Offspring Exposed to Folic Acid During Pregnancy

Does Folic Acid Decrease Preeclampsia Rates in Those at Risk?

What is the Impact of Folic Acid Supplementation on Postnatal Brain Development