Abstract
BACKGROUND: Postpartum depression and anxiety are common and burdensome. Physical activity (PA) is a scalable intervention, yet the comparative effectiveness of PA modalities and optimal dosing in the postpartum period remain uncertain. To compare the effects of different PA modalities on depressive symptoms, anxiety, and quality of life (QoL) in postpartum women, and to characterize dose–response relationships. METHODS: PubMed, Embase, Cochrane CENTRAL, Web of Science, and Google Scholar were searched from inception to 31 July 2025. Eligible studies were randomized controlled trials with postpartum assessment, testing structured PA against usual care, attention control, waitlist, or an alternative PA; minimum duration four weeks. Outcomes included depressive symptoms, anxiety, or QoL assessed with validated scales (e.g., EPDS (Edinburgh Postnatal Depression Scale), BDI (Beck Depression Inventory), CES-D (Center for Epidemiologic Studies Depression Scale), STAI (State Trait Anxiety Inventory), HADS-A (Hospital Anxiety and Depression Scale anxiety subscale), and SF-12 or SF-36 (Short Form Health Survey)) within 12 months postpartum. Effect sizes were standardized mean differences (SMDs) with 95% confidence intervals. Random effects pairwise meta analyses, Bayesian network meta-analysis to rank modalities, and model based dose–response analyses using weekly PA dose in MET minutes (one MET equal to approximately 3.5 millilitres of oxygen per kilogram per minute at rest) were performed. RESULTS: Twenty nine trials including 3,915 postpartum women were eligible. Compared with control, PA reduced depressive symptoms (SMD − 0.55, 95% CI − 0.78 to − 0.32) and anxiety (SMD − 0.72, 95% CI − 1.13 to − 0.30), and improved QoL (SMD 0.43, 95% CI 0.23 to 0.63). Network meta analysis showed multicomponent and mind–body PA reduced depression versus control (multicomponent SMD − 1.08, 95% CI − 1.94 to − 0.22; mind–body SMD − 0.91, 95% CI − 1.45 to − 0.38). Mind–body PA lowered anxiety versus control (SMD − 1.16, 95% CI − 1.74 to − 0.57) and versus aerobic PA (SMD − 1.01, 95% CI − 1.92 to − 0.10), and improved QoL (SMD 1.12, 95% CI 0.12 to 2.12). Dose–response modelling identified non-linearity, with benefits peaking at moderate weekly volumes: depressive symptoms improved most between 370 and 680 MET minutes per week and QoL between 540 and 720. Subgroup findings showed clearer benefits at three or fewer sessions per week for depression (SMD -0.52) and anxiety (SMD -0.59). CONCLUSION: PA within moderate weekly volumes was associated with the greatest improvements in postpartum mental health. Mind–body and multicomponent formats appeared most effective. These findings suggest that engaging in a manageable amount of weekly activity may help optimize improvements in depression and QoL after childbirth. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-026-26566-3.