Associations between physical activity and prenatal depression and anxiety symptoms: a cross-sectional study

Prenatal depression and anxiety pose a significant threat to maternal and neonatal health. Although physical activity (PA) improves mental wellbeing, its effects across pregnancy stages and relationship with sedentary behavior (SB) are not well understood. This study examined the relationships between PA, SB, and prenatal depression and anxiety, investigating differences throughout gestational stages. In this cross-sectional study, 501 pregnant women aged 18–45 completed the International Physical Activity Questionnaire - Short Form (IPAQ-SF), the Center for Epidemiologic Studies Depression Scale (CES-D), and the Generalized Anxiety Disorder-7 (GAD-7). Pearson correlations, linear regression, decision tree analysis, and one-way ANOVA were used to analyze associations and group differences. PA was inversely correlated with depression ( r = −0.637, p < 0.01) and anxiety ( r = −0.655, p < 0.01). Linear regression analysis demonstrated strong explanatory power for both depression ( R 2 = 0.839, adjusted R 2 = 0.836) and anxiety ( R 2 = 0.844, adjusted R 2 = 0.841), with overall significance ( p < 0.001). Sedentary time and weekly MET-minutes were significant predictors ( p < 0.001); increased sedentary time was associated with higher symptom scores, while greater PA was linked to lower depression and anxiety. Decision tree analysis identified a threshold of ≥2,346 MET-min/week as being associated with significantly reduced mental health symptom scores. One-way ANOVA revealed no differences in PA, depression, or anxiety across any stage of pregnancy. Higher levels of PA and reduced sedentary time were significantly associated with improved prenatal mental health. These associations were consistent across gestational stages, highlighting the importance of promoting sustained activity and reducing SB throughout pregnancy.