Postpartum depression (PPD), the most common childbirth complication, has received increasing clinical, public and scientific attention. Characterized by persistent sadness, anxiety, insomnia, disorganized behavior and irritability, PPD typically manifests within 4–6 weeks postpartum but can endure for months or years (American Psychiatric Association (APA), 2013). Globally, PPD affects approximately 17.2% (95% CI: 16.0–18.5%) of postpartum women (Wang et al., 2021) and 23.1% (95% CI: 21.8–24.5%) in low- and middle-income countries (LMICs) (Roddy et al., 2023). Various studies demonstrate that maternal PPD is a significant issue that can steal motherhood, and has a range of effects on the health of the entire family (Ahmadinezhad et al., 2024; Dagher et al., 2020). In fact, PPD can negatively affect the couple’s and parent–child relationship, and increase the risk of adverse infant health outcomes (Dadi et al., 2020) as well as offspring’s physical, behavioral and cognitive developmental outcomes (Gelaye et al., 2016; Sridhar et al., 2025), resulting in substantial humanistic and economic burden affecting the whole society (Margiotta et al., 2022; Moore Simas et al., 2019).

The pathophysiology and etiologies of PPD are complex, multifactorial, and, in most cases, incompletely elucidated (American College of Obstetricians and Gynecologists (ACOG), 2023). Alongside socio-demographic and biological factors, recently many evidences focused on the birth-related contextual variables that constitute significant risk factors for PPD development (Coo et al., 2023; Rados et al., 2022). Results from Grekin et al. (2021) indicated both subjective experiences of childbirth (including perception of support from professionals or others, feelings of control and security) and objective birth characteristics (like childbirth interventions and infant outcomes) were robustly associated with symptoms of posttraumatic stress and depression, supported by relevant evidence that a lower level of satisfaction with childbirth was a significant predictor of a higher risk of PPD (Coo et al., 2023). All these findings strongly suggested that high-quality peripartum care and a positive birth experience can make the psychological adaptation in the early postpartum period easier and have long-lasting effects on maternal wellbeing.

Common health problems or negative experience in the early postpartum period were significant risk factors of PPD. Specifically, the quality of maternal care and support following childbirth plays a crucial role, as it is essential in helping women transition into motherhood and cope with its associated challenges (Silva-Fernandez et al., 2023). Furthermore, a systematic review of infant health outcomes in LMICs suggested adverse infant health outcomes were associated with an increased risk of PPD (Dadi et al., 2020). Negative breastfeeding experiences, e.g., breastfeeding challenges, discomforts, and lack of breastfeeding supports were also reported to precede the onset of depressive symptomatology (Tanganhito et al., 2020; Yuen et al., 2022). Conversely, exclusive breastfeeding may exert a protective effect against PPD (Lubis et al., 2024; Shimao et al., 2021). While previous studies have provided valuable insights into the risk and protective factors for PPD development and persistence, these correlates are often examined in isolation. However, pregnancy, childbirth, and the postpartum period represent interconnected experiences that likely interact to shape maternal emotional and biological vulnerabilities, culminating in conditions such as PPD.

Due to the complex interaction among related variables, standard regression models or parametric statistical methods can hardly express such relationships (generally nonlinear) (Arora et al., 2019; Xu et al., 2018). In contrast, some non-parametric methods such as random forest or other machine learning approaches can be employed to evaluate the effects of risk factors on a given response variable and identify critical factors (Cellini et al., 2022; Zhao et al., 2024). Furthermore, Bayesian network can be used to explore direct and indirect effects among sets of factors, which will provide clues for some potential intervention strategies, such as certain pathways or action (Arora et al., 2019; Lazarov et al., 2020). On the other hand, based on the network structure, we can also identify local structures by community detection methods (Rajeh and Cherifi, 2022), which can help to explore candidate intervention strategies for specific targets and improve health outcomes. However, few studies focused on the system structure and correlates of PPD using network approaches. Therefore, to gain a more comprehensive understanding of the complex nature of how these perinatal and postpartum factors are interconnected, it might be more appropriate to take a network approach.

This prospective observational study examined the prevalence and network structure of postpartum depressive symptoms, and also applied random forest and Bayesian network methods to identify critical perinatal and postpartum factors and pathways influencing PPD among Chinese women. Our findings aim to inform targeted, system-level interventions to mitigate PPD risk and enhance maternal–infant health outcomes.

This prospective observational study applied random forest and Bayesian network to identify central depressive symptoms, critical risk factors, and the complex interplay of perinatal and postpartum factors associated with PPD among Chinese women following vaginal deliveries. By mapping symptom networks and variable interactions, our findings provide actionable insights for targeted interventions to mitigate PPD risk and optimize maternal mental health outcomes.

PPD prevalence was substantial in our cohort, with 26.0% of participants screening positive at 4–6 weeks postpartum. Network analysis identified Anxiety/Worry (EPDS 4) as the most central symptom, demonstrating the highest node strength and robust connections to Sad Mood, Overwhelmed, Self-blame, and Panic. This centrality underscores its pivotal role in the PPD symptom network and aligns with evidence suggesting anxiety symptoms may precede comorbid depressive conditions (Falah-Hassani et al., 2017; Phua et al., 2020). Sad Mood (EPDS 8) and Overwhelmed (EPDS 6) emerged as secondary central nodes, potentially reflecting distress driven by perceived challenges in meeting maternal demands during this critical adjustment period (Gao et al., 2010; Kristensen et al., 2018). Critically, targeting these central symptoms in clinical practice—through enhanced professional and family support to alleviate parenting stress and improve emotional regulation—may disrupt symptom deepening and mitigate PPD severity.

Breastfeeding challenges emerged as the predominant risk factor for PPD in our study, demonstrating the highest RF among all predictors. This finding aligns with systematic reviews linking breastfeeding challenges to adverse mental health outcomes (Yuen et al., 2022). Notably, 43.2% of women reported breastfeeding challenges, underscoring its clinical significance during the early postpartum period. Conversely, family support for breastfeeding (both psychological and behavioral support) constituted a key protective factor, a finding that underscores the fundamental role the family network plays in shaping mother’s breastfeeding self-efficacy and related outcomes (García-Fernández et al., 2023; Hu et al., 2025). This is also consistent with findings from a prospective cohort study in Canada (Chaput et al., 2016) that women’s perception of breastfeeding support significantly modified the primary association between breastfeeding difficulties and PPD. As highlighted in the Lancet Breastfeeding Series (Perez-Escamilla et al., 2023), negative breastfeeding experiences are primary reasons for prematurely stopping breastfeeding. Therefore, it is recommended to integrate family-centered education into prenatal and postnatal care, with clearly defined evidence-based support strategies to optimize breastfeeding experiences and reduce the risk of PPD.

Physical health conditions of both the mother and baby also play a key role in the occurrence of PPD. Women with physical problems and adverse infant outcomes are vulnerable to psychological disorders (Capik and Durmaz, 2018; Dadi et al., 2020), as the discomforts and increased stress due to poor health conditions can lead certain common symptoms (like fatigue and worry) into a network of depressive symptoms (Baez et al., 2021). Therefore, postpartum visits, remote counseling and ongoing postpartum care should be advocated to timely identify mother and baby’s health issues and provide services and support corresponding to each woman’s individual needs.

Regarding childbirth-related factors, SSC duration and childbirth experiences also stood out and shared indirect connections with PPD. While univariate analysis showed no significant EPDS score differences across SSC durations, random forest modeling identified SSC duration as a clinically relevant PPD predictor, a novel finding highlighting machine learning’s utility in detecting complex relationships obscured by traditional methods (Cellini et al., 2022). This aligns with WHO recommendations for early essential newborn care (EENC), which emphasize immediate and sustained SSC (World Health Organization, 2022). Previous evidence also suggested close physical contact with infants may activate the maternal oxytocinergic system that modulate attachment bond formation (Markova and Siposova, 2019), promote parenting self-efficacy and alleviate stress and anxiety (Huang et al., 2022). However, there are still divergent recommendations for SSC duration, and the evidence on the optimal duration of SSC for maximum benefits remains uncertain (Li et al., 2024). Further studies are necessary to confirm the psychological benefits of SSC for women and to explore the dose–response relations.

Crucially, women’s self-perception and own capacity involved in the whole childbirth process emerged as key PPD determinants, consistent with the study by Rados et al. (2022) that women’s personal attributes, including feeling anxiety or being in control during childbirth, have prolonged effect on postpartum mental wellbeing. The importance of women’s involvement in their own maternity care is well-established, with shared decision-making and autonomy being recognized as critical elements that positively impact the birth experience and overall satisfaction (World Health Organization, 2018; Deherder et al., 2022). Our finding that non-pharmacological pain relief was strongly connected with key aspects of the childbirth experience reinforces this, highlighting the importance of incorporating humanistic practices that offer women more choices. Therefore, to improve maternal mental health, it is imperative that healthcare institutions not only promote women’s active participation but also systematically monitor their perceptions and experiences of maternity care to guide quality improvement.

Hospital type served as a central bridging node within the network, strongly connected with factors related to peripartum care services, childbirth experience and PPD. However, its centrality likely reflects not the intrinsic properties of institutional classification, but rather the aggregation of systemic disparities—including socioeconomic stratification (parity, education level, household registration, etc.), differential clinical practices (labor pain management, SSC), and diverging maternal health trajectories (pregnancy complications, breastfeeding challenges, etc.)—that become embedded within specific hospital types. This pattern suggests that hospital type operates as a conduit for pre-existing vulnerabilities and varied care ecosystems, collectively shaping psychological outcomes. As the focus of China’s maternal and child healthcare has shifted from survival toward thriving (Qiao et al., 2021), our results underscore that institutional labels alone cannot drive progress. Policymakers must transcend hospital-centric paradigms by standardizing evidence-based, humanized practices (e.g., nonpharmacy pain relief, companion support, prolonged SSC) across all facilities, while simultaneously addressing upstream determinants that funnel vulnerability into specific care pathways. Only through this integrated approach—simultaneously standardizing high-quality perinatal care and addressing systemic inequities—can we effectively mitigate PPD risk and improve maternal psychological wellbeing.

This study identified the central symptoms and important perinatal and postpartum factors that may trigger or exacerbate PPD. The high centrality of Anxiety/Worry, Sad mood and Overwhelmed in the depressive symptom network suggests that providing sufficient professional and family support to reduce those common early symptoms is critical for maintaining maternal mental wellbeing. The Bayesian network reflects the complexity of the interrelation between PPD and relevant factors, highlighting the importance of breastfeeding experience as well as maternal and infant health condition in the early postpartum period for PPD development. Our findings also revealed that hospital type served as a critical bridging node centrally embedded within the network. To effectively mitigate PPD risk and improve maternal mental health, policymakers must shift beyond facility-focused approaches by implementing evidence-based, humanized practices (e.g., nonpharmacy pain relief, prolonged SSC, tailored breastfeeding support) across all facilities, while simultaneously addressing upstream structural determinants that funnel vulnerability into specific care pathways. In conclusion, the network approach used in this study provides a more comprehensive insights into the important nodes and mechanisms underlying maternal mental health, which are of great value for health professionals to develop targeted interventions to prevent the development of PPD.