BACKGROUND: Mindfulness helps reduce negative emotions, but its ability to prevent postpartum psychological problems remains unclear. This study aimed to assess the effects of mindfulness-based interventions (MBIs) during pregnancy on postpartum mental health, especially postpartum depression. METHODS: Online databases regarding the effect of mindfulness on pregnancy were searched and a meta-analysis was conducted. RESULTS: Eight randomized controlled trials (RCTs) and a self-controlled study were included. We found consistent results showing that MBIs significantly improve the depressive symptoms of all pregnant women in both the case-control (SMD = -0.90, 95 % CI (-2.71, -1.82), p = 0.01) and self-control (SMD = 1.24, 95 % CI (0.37, 2.11), p = 0.005) comparisons. However, MBIs were ineffective for high-risk pregnant women with severe depressive symptoms before delivery in both the case-control (SMD = -1.07, 95 % CI (-3.40, 1.25), p = 0.36) and self-control comparisons (SMD = 2.10, 95 % CI (-0.26, 4.47), p = 0.08). Furthermore, MBIs did not have significant advantages over other intervention methods (SMD = -0.45, 95 % CI (-1.17, 0.28), p = 0.23). LIMITATIONS: There were few high-quality RCTs, and the sample size was small. CONCLUSION: MBIs can relieve maternal depressive and anxiety symptoms, especially for the prevention of postpartum depression in healthy pregnant women. However, MBIs do not have significant advantages over other interventions and may not be useful for all pregnant women. These findings contribute to the optimization of perinatal mental health intervention programs and the improvement of pregnancy outcomes, playing an important guiding role in clinical decision-making.