Cholecalciferol in pregnancy and child autism and ADHD
What it found
High-dose cholecalciferol taken in pregnancy did not change the chance of autism or ADHD in the children at age 10.
Higher vitamin D levels in mothers before the supplements began went with lower chances of autism and ADHD.
What they found
Studies in people
Autism diagnoses
At age 10, 5 children (2.0%) in the high-dose group and 7 children (2.8%) in the standard dose group were diagnosed with autism. The authors found no difference between the groups.
ADHD diagnoses
ADHD was diagnosed in 27 children (11%) in the high-dose group and 31 children (12.4%) in the standard dose group. The authors found no difference between the groups.
Symptoms of autism and ADHD
Clinically rated symptoms of autism were present in 15 children (6.1%) in the high-dose group and 25 children (10%) in the standard dose group. Symptoms of ADHD were present in 67 children (27.2%) and 76 children (30.4%) respectively. The authors found no significant difference.
Vitamin D levels before supplements
Higher vitamin D levels in mothers before the supplements began went with a lower chance of autism, lower autistic symptom scores, and a lower chance of an ADHD diagnosis. This link was not found for ADHD symptom scores.
Vitamin D levels after birth
Vitamin D levels in mothers after the supplements, and in children at 6 months and 6 years, were not linked to autism or ADHD.
Parent-rated symptoms
Parents' ratings of autistic traits and ADHD symptoms showed no significant links with the supplements or with vitamin D levels. Some estimates suggested lower autistic trait scores with higher vitamin D levels in mothers before supplements and in children at 6 months.
What the authors conclude
“Higher maternal preintervention 25(OH)D was associated with a decreased risk of autism, lower autistic symptom load, and decreased risk of ADHD diagnosis, but high-dose vitamin D3 supplementation in pregnancy had no effect on risk of autism and ADHD.”
Also in their conclusions
- They conclude that higher vitamin D levels in mothers before the supplements began were linked to a lower chance of autism, lower autistic symptom scores, and a lower chance of an ADHD diagnosis.
- They conclude that high-dose cholecalciferol from week 24 of pregnancy until 1 week after birth did not lower the overall chance of autism or ADHD diagnoses or symptoms in the children at age 10, compared with the standard dose.
- They say future studies on vitamin D and autism should be aware of possible non-linear links.
How it was done
Vitamin D deficiency in pregnancy may increase the risk of autism and ADHD. No randomised trials had yet tested whether giving vitamin D in pregnancy changes these risks.
They studied 623 pregnant women in Denmark, split into two groups. One group took 2800 IU of cholecalciferol daily and the other took 400 IU daily, from week 24 of pregnancy until 1 week after birth. At age 10, 496 of their children had a clinical check for autism and ADHD.
What it can’t tell you
- The study had few cases of autism, which the authors say may explain why no overall effect of the supplements was found.
- The authors could not tell whether a higher dose started earlier in pregnancy, or before pregnancy, would have made a difference.
- The link between higher vitamin D levels before supplements and lower autism and ADHD chances may be affected by other lifestyle factors, so it does not prove cause and effect.
Who paid
- Funding
- Funded by European Research Council (from the PubMed record).
- Authors work at
- University of Copenhagen, Denmark; Copenhagen University Hospital - Mental Health Services CPH, Denmark; University of Southern Denmark, Denmark
The paper
- Title
- High-dose vitamin D3 supplementation in pregnancy and risk of neurodevelopmental disorders in the children at age 10: A randomized clinical trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Aagaard K, Møllegaard Jepsen JR, Sevelsted A, et al (2024). High-dose vitamin D3 supplementation in pregnancy and risk of neurodevelopmental disorders in the children at age 10: A randomized clinical trial. The American journal of clinical nutrition. doi:10.1016/j.ajcnut.2023.12.002Free full textPubMed 38072183DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error