Motherhood is widely recognized as a transformative and emotionally fulfilling life event (1). However, a significant proportion of pregnant women experience psychological distress during gestation (2). Hormonal fluctuations and evolving responsibilities contribute to the emergence of mental health disorders such as depression and anxiety, which pose significant threats to maternal wellbeing (3). These conditions, clinically characterized by persistent low mood, fatigue, excessive worry, sleep disturbances, and diminished engagement in daily activities (4, 5), have garnered increasing attention in global health discourses. Epidemiological data from the World Health Organization (WHO) indicates that approximately 10%–13% of expectant mothers worldwide exhibit depressive symptoms, while an even larger cohort (15%–20%) demonstrates anxious symptomatology (6, 7). Corresponding figures from the Centers for Disease Control and Prevention in the United States reveal prevalence rates of 14%–23% for antenatal depression and 10%–15% for anxiety disorders (8, 9). Comparable findings have been reported by the UK’s National Health Service, documenting moderate-to-severe psychological distress in approximately 12% of pregnant women (10).

Pregnancy can exacerbate psychological distress due to hormonal changes, physical discomfort, and stress related to future uncertainties (11). External stressors such as low socioeconomic status, inadequate social support, and unemployment demonstrate significant associations with increased risk of antenatal mental health disorders (12). These untreated conditions are linked to diminished daily functioning and elevated risks of adverse pregnancy outcomes including gestational hypertension, low birth weight, and preterm delivery (13). Maternal mental health also influences fetal neurodevelopment and infant behavioral regulation, with consequences often persisting into early childhood (14, 15). The management of antenatal mental health carries substantial public health implications extending beyond individual well-being. Epidemiological evidence reveals correlations between maternal anxiety and depression during pregnancy and increased incidence of behavioral and emotional disorders in offspring (15). Furthermore, untreated prenatal depression serves as a established predictor of postpartum depression, which may substantially impair mother-infant bonding and long-term family dynamics (16). These cascading effects highlight the necessity of developing accessible, scalable, and safe preventive interventions for implementation during pregnancy.

Physical activity (PA) has emerged as a significant low-cost, non-pharmacological intervention for mental health. Substantial evidence demonstrates its effectiveness in enhancing both physical and mental health outcomes (17, 18). The WHO recommends that all adults, including pregnant women, engage in at least 150 min of moderate-intensity aerobic PA weekly to maintain optimal health (19). Exercise physiologically increases neurotransmitter levels, particularly endorphins, serotonin, and dopamine, which play crucial roles in mood regulation and emotional resilience (20). Pregnancy, however, presents unique physical and emotional challenges that may influence an individual’s capacity and motivation to maintain activity levels. Nevertheless, moderate-intensity exercise during pregnancy demonstrates multiple health benefits, including reduced risk of gestational diabetes mellitus, improved cardiovascular function, and enhanced weight management (21). Notably, PA during pregnancy correlates with decreased anxiety and depressive symptoms. Empirical studies indicate that regular PA participation enhances body image perception, strengthens self-efficacy beliefs, improves social connectivity, and promotes effective emotional regulation (22). These psychosocial advantages hold particular significance during pregnancy, a period when many women experience heightened emotional vulnerability and sensitivity.

While the physical benefits of prenatal exercise are well-established, its psychological effects remain underexplored. Recent evidence indicates suboptimal PA levels among pregnant women (23). Existing literature from China and other regions has seldom examined the synergistic relationships between PA and sedentary behavior (SB) with antenatal depression and anxiety. Few studies have explored how these associations differ across gestational stages (24), despite recognized physiological and emotional transformations that may influence mental health trajectories (25). Elucidating these stage-specific dynamics is crucial for developing personalized non-pharmacological interventions to enhance maternal psychological wellbeing (26). Emerging research identifies SB as an independent risk factor for adverse psychological outcomes (27), necessitating differentiation between beneficial rest and prolonged inactivity during pregnancy (28). However, comprehensive investigations simultaneously evaluating both PA and SB across all trimesters remain scarce. The present study systematically investigates the associations of PA and SB with depressive and anxiety symptoms in pregnant women, while exploring potential variations across gestational stages. Through multivariable linear regression and decision-tree analyses incorporating sociodemographic and health-related covariates, we aim to establish a data-driven PA threshold associated with reduced psychological symptomatology, thereby enhancing clinical applicability. This research seeks to generate evidence-based recommendations for prenatal mental health management and inform trimester-specific targeted interventions. The findings may advance clinical and public health practices by improving maternal emotional wellbeing and pregnancy outcomes, while contributing to standardized prenatal PA guidelines.

Pregnant women face substantial mental health challenges, with depressive and anxiety symptoms among the most prevalent. In this study, higher PA was associated with lower CES-D and GAD-7 scores. In contrast, greater SB was associated with higher psychological-symptom burden. Based on the descriptive data, participants in this study reported a mean CES-D score of 25.39 ± 11.60 (95% CI: 24.38–26.40) and a mean GAD-7 score of 8.14 ± 7.42 (95% CI: 7.49–8.80), consistent with an elevated average symptom burden in this antenatal cohort (30–32). Considering that CES-D scores ≥16 and GAD-7 scores ≥5 represent established screening thresholds, these cutoff values indicate that a significant proportion of women exhibited clinically meaningful psychological distress (31). When interpreting the observed associations between PA, SB, and mental health outcomes within this cohort, these contextual considerations warrant careful attention (23). Interestingly, we observed no between-trimester differences in mean PA or symptom levels. These findings suggest that promoting PA while reducing SB could represent effective non-pharmacological interventions for enhancing prenatal mental health, pending confirmation through longitudinal and interventional studies. These insights may inform the development of continuous prenatal mental healthcare frameworks by offering practical approaches to mitigate psychological distress during pregnancy and influence public health policy formulation. Consistent with prior research (40), our study demonstrates PA’s positive association with pregnant women’s mental health, revealing inverse relationships between PA levels and depressive/anxiety symptoms, alongside direct correlations between sedentary time and psychological symptomatology. The observed detrimental effects of prolonged sitting on mental wellbeing might stem from metabolic dysregulation and systemic inflammation promotion (41), thereby highlighting PA’s potential as an accessible, non-pharmacological intervention for perinatal mental health management.

We observed positive associations between PA and anthropometric indicators including weight, body mass index (BMI), parity, and maternal age. These correlations suggest that physiological adaptations and lifestyle modifications during pregnancy may facilitate increased PA levels. In contrast, SB demonstrated significant positive associations with higher educational attainment, full-time employment status, and household income levels. This sociodemographic pattern aligns with existing literature examining occupational SB patterns and their mental health implications (42). Our analysis revealed no significant differences in PA-related mental health benefits across trimesters, a finding consistent with previous longitudinal investigations (43). While accumulating evidence supports PA’s protective effects against perinatal psychological morbidity, prior studies have not systematically examined gestational stage-specific variations in these associations. Our results substantiate continuous mental health benefits of PA throughout pregnancy, reinforcing clinical recommendations for maintaining moderate-intensity exercise across all gestational phases. Longitudinal analyses demonstrate typical PA trajectories peak during mid-pregnancy before declining in later stages due to progressive physical constraints (44). These temporal variations likely result from multifactorial influences including social support networks, medical counseling, and individual adaptive capacities. Targeted interventions are therefore essential to support sustained PA during late pregnancy when women often require additional assistance.

PA may promote mental health through multiple biological mechanisms, including endorphin release and regulation of key neurotransmitter systems (45). Endorphins, the body’s endogenous opioid peptides, play crucial roles in enhancing mood and alleviating pain perception. Moderate-intensity exercises such as brisk walking or light jogging demonstrate particular efficacy in stimulating endorphin secretion (46), thereby improving psychological well-being while reducing anxiety and depressive symptoms. The physiological elevation of endorphin levels during pregnancy facilitates pain modulation during labor (47), an effect that can be amplified through moderate-intensity exercise which concurrently stabilizes emotional tone (48). Additionally, PA exerts mood-enhancing effects via upregulation of serotonin and dopamine signaling pathways (49). Exercise increases serotonin biosynthesis while attenuating its metabolic degradation, resulting in improved affective regulation, sleep quality, and reduced depressive symptomatology (50). The activation of dopaminergic pathways during PA engages the brain’s reward circuitry, promoting enhanced motivational drive, pleasure perception, and life satisfaction. These coordinated neurochemical adaptations collectively contribute to improved emotion regulation capacity and stress resilience (51). PA plays a critical role in regulating the hypothalamic–pituitary–adrenal (HPA) axis, which governs the body’s stress response mechanisms (52). Cortisol, a hormone indispensable for maintaining pregnancy and fetal development, undergoes physiological elevation during gestation; however, chronically elevated concentrations may compromise maternal and fetal wellbeing (53, 54). Moderate aerobic exercise maintains stable cortisol concentrations, thereby stabilizing mood fluctuations and reducing chronic stress exposure (55). PA stimulates the release of neurotrophic factors from the brain that enhance cognitive function and neural plasticity (56, 57). These neurotrophic factors are particularly crucial for facilitating maternal physiological adaptation during gestation and supporting fetal neurodevelopment (58, 59). Exercise training enhances brain-derived neurotrophic factor production, facilitates emotional regulation, promotes neuronal growth, and modulates cortisol homeostasis through HPAA regulation (60). This neurobiological mechanism strengthens psychological resilience while alleviating anxiety and depressive symptomatology (61).

In addition to its physical effects, PA improves psychological health through enhanced self-efficacy, distraction from negative thoughts, and improved body image (62, 63). Increased self-efficacy - the belief in one’s capacity to overcome challenges - contributes to emotional stability and resilience (64). Regular exercise promotes feelings of accomplishment and perceived control, which may enhance maternal confidence and facilitate postpartum recovery. Specifically, yoga and brisk walking enable psychological detachment from stressors while reducing rumination. These activities provide cognitive resets that help regulate mood and mitigate anxiety. Furthermore, PA positively influences body image, which frequently undergoes significant changes during pregnancy (65). Given the high prevalence of body dissatisfaction during this period (66), low-intensity exercises and yoga practices can enhance bodily awareness and acceptance, thereby promoting psychophysical harmony. Conversely, prolonged SB adversely affects metabolic function, inflammatory processes, and hormonal balance, potentially exacerbating mental health issues. Extended sitting periods reduce energy expenditure, exacerbate insulin resistance, and promote dysglycemia, all of which may intensify anxiety and depressive symptoms. Chronic inactivity also induces systemic low-grade inflammation that disrupts neurochemical pathways implicated in mood regulation. Additionally, sedentary lifestyles correlate with elevated cortisol secretion (67), establishing a pathological cycle involving heightened stress responses and inflammatory activation (68). These interrelated mechanisms collectively amplify physiological and psychological stress burdens during pregnancy. Our findings suggest that moderate PA modulates these pathways by improving metabolic and inflammatory markers while safeguarding maternal and fetal wellbeing (69). SB may exacerbate psychological stress through disruption of sleep architecture and dietary quality. Prolonged inactivity has been shown to disturb circadian rhythmicity and sleep continuity, both critical for psychological homeostasis (70). Moreover, SB demonstrates strong associations with suboptimal dietary intake, which negatively affects neurotransmitter balance and emotional regulation. Beyond these behavioral pathways, multiple unmeasured psychosocial and lifestyle variables likely simultaneously influence PA levels and sedentary duration in this investigation (71). For example, compromised sleep quality during gestation could simultaneously reduce daily movement and intensify anxiety/depressive symptomatology, thereby artificially strengthening observed PA-mental health relationships (72). Similarly, individuals perceiving insufficient social support might increase time spent in sedentary pursuits within domestic settings, heightening affective vulnerability (73). Dietary practices characteristically accompanying sedentary lifestyles may worsen mood instability through metabolic or inflammatory pathways (74). Given the absence of direct measurements for these covariates, residual confounding cannot be entirely excluded from consideration.

This study underscores the critical role of PA in prenatal mental health management and offers actionable recommendations for clinical practice and public health policy. Our findings demonstrate that higher PA levels significantly reduce depressive and anxiety symptoms, while prolonged SB exacerbates these conditions. These results emphasize the importance of promoting moderate-intensity PA and minimizing SB during pregnancy. For individuals maintaining prolonged sitting patterns, such as full-time workers or stay-at-home mothers, integrating brief, frequent activity breaks into daily schedules may effectively reduce sedentary time. High-risk individuals with severe depression or anxiety symptoms should receive personalized, stage-appropriate exercise guidance to ensure safety and optimize benefits. The absence of significant differences across trimester-specific analyses suggests these interventions can be safely implemented throughout gestation. Decision tree analysis further substantiates this by identifying specific MET-minute thresholds associated with reduced mental health risks. Notably, our data-driven analysis identified 2,346 MET-minutes/week as a reference value indicating improved mental health outcomes at higher activity levels. However, this threshold must be contextualized within clinical safety parameters, as self-reported PA data from IPAQ-SF typically overestimate actual activity levels by up to 84% compared to objective measurements (75). Consequently, while this threshold provides valuable insights into dose–response relationships between PA volume and prenatal mental health, it should not serve as a universal clinical guideline. Current WHO guidelines recommending ≥150 min/week of moderate-intensity aerobic PA for pregnant women remain appropriate for substantial health benefits. They may gradually make their way up to 300 min a week as they feel comfortable (76). Other professional groups have also made similar suggestions. For example, the 2019 Canadian guideline for PA throughout pregnancy and the ACOG Committee Opinion No. 650 both say that women should do 150 min of moderate-intensity activity per week, with adjustments made based on their health and stage of pregnancy (77–79). Our data indicate that elevated activity levels correlate with diminished symptoms of anxiety and depression; however, clinical recommendations must be tailored to each woman’s health status, physical abilities, and stage of pregnancy.

Low-impact activities are especially beneficial for pregnant women in the third trimester as it reduce the risk of injury while providing health benefits without putting too much pressure on joints or increasing physical discomfort (40, 78, 80). For individuals with low baseline activity levels, gradual progression of PA intensity is recommended over abrupt transitions to excessive exertion, thereby minimizing fatigue-related risks (79). Implementation of individualized PA interventions requires concurrent provision of personalized education regarding appropriate exercise intensities to optimize safety and efficacy. Continuous biopsychosocial monitoring combined with dynamic adjustment of activity parameters based on real-time symptom reporting constitutes essential components of safe prenatal exercise programming. Given the inherent variability in maternal physiological responses, healthcare providers must individualize PA prescriptions to maintain mental health benefits while eliminating potential threats to maternal-fetal wellbeing. The high-activity threshold defined in this investigation serves as a reference standard requiring clinical adaptation to accommodate heterogeneous physiological demands across diverse pregnant populations. Public health strategies should prioritize development of scalable, culturally sensitive frameworks promoting sustainable PA engagement throughout gestation, ensuring equitable access for all women regardless of socioeconomic background or gestational stage. Multilevel community interventions integrating evidence-based educational components demonstrate capacity to reduce SB-associated pathologies while simultaneously improving perinatal mental health trajectories and longitudinal maternal-child health outcomes.

Based on these findings, we suggest that healthcare organizations, government agencies, and communities work together to include prenatal PA promotion in public health education programs. During regular prenatal visits, healthcare providers can suggest specific activities and talk about the dangers of being inactive for long periods of time. Community-based programs that make exercise easy to get to can create supportive spaces that encourage people to keep doing moderate PA. These strategies can work together to improve the mental health of the mother, the development of the fetus, and the outcome of the pregnancy.

This cross-sectional study explored association between PA and depressive/anxiety symptoms in pregnant women, identifying relationships between activity levels and prenatal mental health. The findings indicate that higher PA is associated with lower CES-D and GAD-7 scores, whereas greater SB was associated with higher symptom levels. These associations were observed across trimesters in this sample, however, equality of associations by trimester was not established without formal moderation tests. Maintaining PA and limiting SB may be relevant throughout gestation when medically appropriate and absent contraindications. Public health and antenatal services may consider integrating brief, trimester-appropriate counseling that encourages moderate PA and reduces prolonged sitting, especially for pregnant women who screen positive for psychological distress. Limitations include the cross-sectional design and reliance on self-reported measures; therefore, the observed associations should be confirmed in longitudinal and intervention studies, preferably with device-based assessment of PA and SB.