Study: Vitamin D Levels During Pregnancy Linked with Child IQ, Disparities Among Black Women

According to lead study author Melissa Melough, as many as 80% of Black pregnant women in the United States may be deficient in vitamin D.

A recent study has found that mothers’ vitamin D levels during pregnancy were associated with their children’s IQ, suggesting that higher vitamin D levels in pregnancy may lead to greater childhood IQ scores. Further, the study, published in The Journal of Nutrition, identified significantly lower levels of vitamin D among Black pregnant women.

According to lead study author Melissa Melough, as many as 80% of Black pregnant women in the United States may be deficient in vitamin D. Out of the women who participated in the study, approximately 46% of the mothers were deficient in vitamin D during pregnancy and vitamin D levels were lower among Black women compared with White women.

The researchers used data from a cohort in Tennessee called the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. In the CANDLE study, researchers recruited pregnant women to join the study starting in 2006 and collected information over time about their children’s health and development.

After controlling for several other factors related to IQ, higher vitamin D levels in pregnancy were associated with higher IQ in children 4 to 6 years of age.

“Vitamin D deficiency is quite prevalent,” Melough said in a press release. “The good news is there is a relatively easy solution. It can be difficult to get adequate vitamin D through diet, and not everyone can make up for this gap through sun exposure, so a good solution is to take a supplement.”

Americans consume less than 200 IU in their diet on average, according to the study. Melough predicts this will cause more people to become vitamin D deficient if the pattern of not making up the gap through sun exposure or supplementation continues. Although fatty fish, eggs, and fortified sources, such as cow’s milk, contain higher levels of vitamin D, the study authors note that vitamin D is one of the most difficult nutrients to get in adequate amounts from our diets.

Additional research is needed to determine the optimal levels of vitamin D in pregnancy, but the study authors hope these findings will help to develop nutritional recommendations for pregnant women. Nutritional supplementation and screening may be an impactful strategy for reducing health disparities, especially among Black women and those at high risk for vitamin D deficiency.


Vitamin D levels during pregnancy linked with child IQ, study shows disparities among black women. Seattle Children’s Hospital. Published November 2, 2020. Accessed November 3, 2020.

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