Third-trimester nutrition: Prenatal diet could shape child’s mental health, experts flag
Prenatal diet — particularly in the third trimester — may influence the risk of mental health disorders in the child, new research from Oregon Health & Science University (OHSU) suggests. The study highlights the potential impacts of maternal nutrition on infant neurodevelopment and adds to a growing body of research on how prenatal health factors shape early brain function.
The study examined how maternal dietary choices affect infant behavioral outcomes. The results suggest that consuming high-glycemic index foods — such as white bread, packaged cereals, chips, and crackers — during pregnancy correlated with increased risk factors for mental health disorders in infants.
“These findings highlight opportunities to enhance nutrition during pregnancy and improve offspring outcomes by providing specific dietary targets and time points that can make a difference in infant behavioral health,” says Dr. Elizabeth Wood, lead author and assistant professor of psychiatry at the OHSU School of Medicine.
“They also further emphasize the critical importance of policies and systems that support access, affordability, and education around consuming healthy diets during pregnancy. By advancing interventions that focus on optimizing nutrition during pregnancy, we can better support a baby’s developing brain.”
The diet and mental health correlation
Published in Scientific Reports, the study involved more than 300 pregnant participants who reported their dietary intake, underwent in-laboratory body composition assessments and provided blood samples during their second and third trimesters.
The research team then used the data to calculate each participant’s average dietary glycemic index — a measure of how different foods impact blood sugar levels.
When the participants’ infants reached about six months of age, caregivers completed behavioral questionnaires, and researchers conducted lab-based assessments to evaluate the infants’ emotional regulation — an early indicator of potential mental health risks.
Results reveal an association between high-glycemic diets and behavioral markers linked to mental health disorders. Notably, this effect was observed only in the third trimester, suggesting a critical window for dietary influence on fetal brain development.
The study reveals that prenatal diets that are high in sugar may impact the emotional development of children.
“As a physician, my goal is to help patients feel that they have optimized their food choices so their child can have the healthiest start in life,” Dr. Jamie Lo, an associate professor of obstetrics and gynecology in the OHSU School of Medicine, underscores. “While we know nutrition is important throughout the entire pregnancy, these findings indicate the third trimester is a critical window for maternal dietary quality.
“As it is common for patients to establish prenatal care after the first trimester, this presents an opportunity for health care providers to still intervene during pregnancy and potentially improve mental health outcomes in children.”
Improving nutrition for generations
According to the researchers, the study reinforces the importance of targeted nutritional recommendations during pregnancy. Experts at the OHSU Center for Women’s Health have developed the My Pregnancy Plate model, which emphasizes balance, variety, and moderation to support expectant mothers’ nutrition.
The center also provides one-on-one counseling with registered dietitians to help patients optimize their dietary choices for both their health and their baby’s development.
At the same time, recent research shows that sticking to USDA guidelines during pregnancy can reduce the risk of infant obesity, while a Danish study linked adherence to the Western diet to increased risk of neurodivergence in children.
Looking forward, the researchers say they plan to investigate optimal pregnancy diets further with the goal of improving access to nutritious foods and developing nutritional interventions that could reduce the risk of mental health disorders in children.
“If you intervene during pregnancy, you’re offering knowledge and tools not only to the pregnant person but also to their child and then potentially their children after that,” Sullivan concludes. “You’re shaping the health of generations to come.”
