Adherence to unhealthy dietary patterns may alter the risk of mental disorders during pregnancy and the postpartum period.

To analyze the association between prepregnancy dietary patterns and prospective variations on anxiety symptoms from midpregnancy to early postpartum.

A prospective cohort of 207 healthy pregnant women was followed at 5 to 13, 20 to 26, and 30 to 36 gestational weeks, and once at 30 to 45 days postpartum. The State-Trait Anxiety Inventory was used to evaluate anxiety symptoms at the second and third gestational trimesters and during the postpartum period. Dietary intake was assessed using a food frequency questionnaire administered during the first trimester of pregnancy that referred to the 6 months before pregnancy. Principal components analysis was used to identify dietary patterns and three prepregnancy dietary patterns were identified: common-Brazilian, healthy, and processed. Three longitudinal mixed-effect models were estimated to verify the association between dietary patterns and anxiety symptoms, adjusted for confounding variables.

The mean anxiety symptom scores were 40.4, 40.5, and 37.2 for the second trimester, third trimester, and postpartum, respectively. The rate of variation of the State-Trait Anxiety Inventory score was 0.535 (95% CI –0.035 to 1.107; P=0.066) and –0.010 (95% CI –0.018 to –0.002; P=0.019) when accounting for gestational age and quadratic gestational age, respectively. The common-Brazilian pattern, comprised mainly of rice and beans (β=–1.200, 95% CI –2.220 to –0.181; P=0.021), and the healthy pattern comprised mostly of vegetables, fruits, fish, and tea (β=–1.290, 95% CI –2.438 to –0.134; P=0.029), were negatively associated with prospective changes in anxiety symptoms.

High adherence to the common-Brazilian or healthy patterns was negatively associated with higher anxiety symptom scores from mid-pregnancy to early postpartum in this group of Brazilian women.