From Exposure to Intervention: A Scoping Review and Evidence Mapping of Nature-Based Approaches for Postpartum Depression

Background: Postpartum depression (PPD) affects about 15–20% of women worldwide. While observational studies have increasingly linked nature exposure to improved perinatal mental health, the extent to which nature-based approaches constitute a viable non-pharmacological intervention for PPD remains unclear. This scoping review and evidence mapping aimed to systematically characterize the current evidence base for nature-based approaches in PPD and perinatal populations. Methods: We searched PubMed, Web of Science, PsycINFO, Embase, Cochrane Library, Medline, CNKI, and WanFang Data from inception to December 2025. Two independent reviewers screened titles/abstracts and full texts against predefined inclusion criteria, with disagreements resolved through discussion. Empirical studies investigating any nature-based approach (NBA) (e.g., nature exposure, green space, forest therapy) in pregnant or postpartum women were incorporated. The review followed the PRISMA extension for Scoping Reviews (PRISMA-ScR) guidelines. No formal risk-of-bias assessment was conducted, consistent with scoping review methodology. The narrative synthesis and evidence mapping methodology were used to classify findings by population type and research design. Results: Of 1245 screened records, 11 studies fulfilled the inclusion criteria. To address the specific question of nature-based approaches for PPD, we classified evidence by its directness: studies on women with clinically significant PPD symptoms were treated as direct evidence; studies on general perinatal populations were treated as indirect evidence. Evidence mapping uncovered a significant deficiency: there are no randomized controlled trials (RCTs) that have specifically assessed NBA for women with PPD. Direct evidence was confined to two qualitative studies elucidating favorable experiences of nature engagement among postpartum women facing mental health challenges. Indirect evidence from observational studies (n = 10) generally supported associations between exposure to residential green space—especially tree canopy cover—and reduced risk of PPD and psychological distress, although some studies reported null findings. Physical activity was identified as a partial mediator in several studies. Only one pilot RCT focused on general postpartum women, indicating feasibility but not achieving significant depression reduction. Conclusions: Although encouraging observational data suggest a correlation between nature exposure and improved perinatal mental health, robust RCT evidence for structured Nature-Based Interventions in postpartum depression populations is lacking. Subsequent research must formulate and evaluate standardized, theoretically informed NBA protocols specifically tailored for women experiencing PPD.