Purpose. This study aims to describe 10 years of antenatal care and outcomes for women with a severe mental illness (SMI).Methods. A retrospective cohort study of 420 completed pregnancy records over the last 10 years (2007–2017). Findings were compared to the Western Australian (WA) pregnancy data. Antenatal attendance, demographic, obstetric, neonatal and psychosocial variables were analysed using t tests, χ2, ANOVA and odds ratio (OR).Results. Overall, women with a SMI had high rates of comorbidity (47%), antenatal complications, and preterm birth at 12.6% compared to WA mothers (p < 0.001). Those with schizophrenia were at highest risk with increased risk of threatened preterm labour OR 8.25 (95% CI 4.64–14.65), gestational diabetes OR 3.59 (95% CI 2.18–5.91) and reduced likelihood of a spontaneous vaginal birth OR 0.46 (95% CI 0.29–0.71). Late presentation and antenatal attendance for women with SMI were significantly associated with maternal substance use, psychiatric admission during pregnancy, and child welfare involvement.Women with schizophrenia had significantly lower attendance rates at scheduled antenatal care (ANC) appointments than those with bipolar disease (87.1% vs 94%, p = 0.003).Conclusion. Obstetric outcomes are poorer for women with SMI compared to the general population. They have higher rates of medical comorbidities, lifestyle and psychosocial risks factors that are known to contribute to poor obstetric outcomes.Effective delivery of regular and appropriate ANC is essential in addressing these multifactorial risks. Targeted strategies addressing comprehensive medical management, preterm birth prevention, lifestyle modifications and increased psychosocial support could improve both short- and long-term outcomes for these women and their children.