Women with a history or current perinatal mental health (PMH) disorders have an increased risk of adverse perinatal outcomes including preterm birth. Midwifery caseload practice (MCP) improves outcomes for women, including a 24% reduction in preterm birth rates. The Australian Clinical Practice Guidelines for PMH recommend MCP for women with PMH, though this is rarely implemented. Our aim was to compare obstetric and perinatal outcomes for women with a history of PMH between MCP and standard models of maternity care. Retrospective cohort study using routinely collected data of women with PMH between 1st January 2018 – 31st January 2021. We compared characteristics and outcomes between groups; adjusted for maternal age, gestational age, ethnicity, smoking, socioeconomic status, BMI, pregnancy complications and severity of mental health disorder. 3028 women with PMH, 352 (12%) received MCP. The commonest diagnosis was anxiety and depression (n=723, 23.9%). Women receiving MCP were younger (mean 30.9 vs 31.3, p=0.03), Caucasian (37.8 vs 27.1, p<0.001), from a postcode of advantaged (31.0% vs 20.2, p<0.001); less likely to smoke (5.1 vs 11.9, p<0.001) and lower BMI (mean 24.3 vs 26.5, p<0.001). Women in MCP had lower odds of preterm birth (adjOR 0.46, 95% CI 0.24-0.86), higher odds of vaginal birth (adjOR 2.55, 95% CI 1.93-3.36), breastfeeding at discharge (adj OR 3.06, 95% CI 2.10-4.55) with no difference in severe adverse neonatal outcome (adj OR 0.79, 95% CI 0.57-1.09). Evidence from this study demonstrates women with PMH who have continuity of midwifery care have improved outcomes compared to women with PMH who receive standard care. This provides further evidence that women are better together through midwifery continuity of care. Future RCTs for this group of women is needed to establish causation.