Abstract
BACKGROUND: Physical activity during pregnancy is regarded as safe and desirable for uncomplicated pregnancy and benefits women's overall health. It was also previously found to be positively associated with neonatal brain cortical development. This study aims to evaluate whether there are associations between maternal physical activity during pregnancy and child cortical brain development and executive function at age 8 years. METHODS: Sixty-nine pregnant women and their children (38 boys and 31 girls) completed the longitudinal and prospective study and were included in this report. Maternal physical activity level was recorded using accelerometer worn on the ankle for 3-7 consecutive days each trimester during the pregnancy. Average daily steps and activity count as well as minutes spent in sedentary/light/moderate/vigorous activity modes were calculated. At age 8 years, their children's brain cortical features including cortical thickness, surface area, volume, and local gyrification index (LGI) were measured using high-resolution 3D T1-weighted MRI. Parent ratings of the children's executive functions were assessed by the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire. The relationships between maternal physical activity level, child brain cortical features, and BRIEF scores were evaluated using Spearman's correlation and linear regression, with child's sex, age, race, BMI, parental socioeconomic status and childhood traumatic experience controlled. RESULTS: Significant positive correlations (R: [0.35, 0.54], FDR-corrected p ≤ 0.05) between maternal physical activity level at different trimesters during pregnancy and child brain cortical features were identified, including cortical surface area and/or cortical volume in the paracentral, supramarginal, and transverse temporal gyri of the right hemisphere, and cortical LGI in widespread brain regions. Additionally, physical activity level during pregnancy negatively correlated (R: [-0.60, -0.43], p ≤ 0.05) with child executive function issues measured by BRIEF subscales of Inhibit, Shift, Emotional Control, and Behavioral Regulation Index. Results obtained from linear regression analyses were consistent, with most of the identified relationships remaining statistically significant. CONCLUSION: We identified significant correlations between maternal physical activity levels during pregnancy and child brain cortical features and executive function at age 8 years. Higher maternal physical activity was associated with better child brain cortical development and less executive function challenges.