High-Dose Vitamin D in Pregnancy Linked to Better Childhood Memory at Age 10: Analysis Reveals
Denmark: A new study published in JAMA Network Open has found that high-dose vitamin D3 supplementation during pregnancy may be associated with improved cognitive performance in children at 10 years of age.
The research, led by Olivia Frigast Frederiksen from the Copenhagen Prospective Studies on Asthma in Childhood at the University of Copenhagen, evaluated whether increasing vitamin D3 intake during pregnancy could influence long-term cognitive outcomes in offspring. While earlier observational studies had suggested a connection between maternal vitamin D levels and child cognition, randomized clinical trial evidence in this area has been limited.
For this purpose, the investigators conducted a post hoc analysis of a blinded, placebo-controlled randomized clinical trial involving mother-child pairs from Denmark. A total of 498 children were included in the final analysis, with nearly equal numbers exposed prenatally to either high-dose vitamin D3 (2800 IU per day) or the standard recommended dose (400 IU per day). Supplementation began at 24 weeks of pregnancy and continued until one week after delivery.
Cognitive outcomes were assessed when the children reached approximately 10 years of age using an extensive neuropsychological test battery as part of the Copenhagen Prospective Study on Neuro-Psychiatric Development. The evaluation covered multiple domains of cognition, including memory, attention, and executive functioning.
The following were the key findings:
- Children exposed to high-dose vitamin D3 during pregnancy showed better performance in certain cognitive domains.
- Improvements were observed in both verbal memory and visual memory compared to the standard-dose group.
- An initial association was noted with improved cognitive flexibility (set shifting), reflecting better ability to switch tasks or adapt thinking.
- The association with cognitive flexibility did not remain statistically significant after adjustment for multiple comparisons.
Overall, the findings suggest that higher prenatal vitamin D3 exposure may support cognitive development, particularly memory functions, reinforcing the role of maternal nutrition in long-term brain health.
The authors acknowledged key limitations, including the post hoc design, which may introduce chance findings. Most participants had adequate baseline vitamin D levels, limiting applicability to deficient populations, and the use of a single assessment at age 10 restricts insight into developmental trajectories.
Despite these constraints, the study offers important randomized evidence linking higher prenatal vitamin D3 intake to improved cognitive outcomes in mid-childhood, warranting further research to confirm findings and define optimal dosing across populations.
Reference:
Frederiksen OF, Jepsen JRM, Brustad N, et al. High-Dose Vitamin D3 Supplementation During Pregnancy and Test-Based Cognitive Performance at Age 10 Years: A Post Hoc Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open. 2026;9(5):e2611464. doi:10.1001/jamanetworkopen.2026.11464
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