How the impact of maternal diet on infant health is strengthened in late pregnancy

In a recent interview with Contemporary OB/GYN, Elinor L. Sullivan, PhD, and Elizabeth K. Wood, PhD, professor and assistant professor, respectively, at Oregon Health & Science University, discussed how the link between maternal diet and infant development is strongest during the third trimester of pregnancy.

The study evaluated diet impacts in the second trimester vs the third trimester, with the latter leading to more significant outcomes. Notably, this effect was only found for diet rather than body composition or metabolic health.

Contemporary OB/GYN:

How does the association between maternal diet and infant development differ between trimesters of pregnancy?

Elizabeth K. Wood, PhD:

Yes, so because we collected this detailed information during the second and third trimesters, we were able to test associations looking at only second trimester variables or looking at only third trimester variables. So that's diet and body composition and insulin sensitivity in the second trimester as it relates to infant mental health or diet in the third trimester, their body composition in the third trimester, and the insulin sensitivity in the third trimester as it relates to infant mental health. And we found effects for the diet, the dietary glycemic index, or that kind of simple sugar components of the maternal diet being related to infant mental health risk later in life. So that is, and that's at 6 months in infant life, and we did not see those same effects with the variables that we collected in the second trimester.

Elinor L. Sullivan, PhD:

We also found it compelling that it was the diet, instead of body composition or metabolic health, that seemed to be more important for the child's behavioral development, and we think that's really compelling, because it's much easier to again, make a small change in the diet than to be able to overly shift your whole metabolic health or body composition, especially during a time of pregnancy, where making big changes in weight or metabolic health is not necessarily recommended. So, we think again, dietary changes will be easier and a more rapid possible change for individuals.

This video is part 2 of a 3-part series. Click here for part 2. Check back Monday for part 3.

References

1. Study confirms link between maternal diet, risk to infant behavioral health. Oregon Health & Science University. March 26, 2025. Accessed March 28, 2025. https://www.eurekalert.org/news-releases/1078391
2. Wood EK, Nomura O, Ablow JC, et al. Higher prenatal dietary glycemic index in the third trimester of pregnancy is associated with infant negative affect at 6 months. Scientific Reports. 2025;15. doi:10.1038/s41598-025-91886-0