Introduction <p>Metabolic and bariatric surgery (MBS) improves long-term metabolic health and fertility in women with severe obesity. However, the extent to which preoperative type 2 diabetes mellitus (T2DM) continues to influence pregnancy outcomes remains unclear. Study aimed to evaluate obstetric and neonatal outcomes depending on T2DM status.</p> Methods <p>This retrospective cohort study included 156 women who conceived after MBS (2015–2024) across 11 Polish bariatric centers. Participants were stratified into three groups: persistent T2DM (PD), T2DM remission (RD), and no preoperative T2DM (CG). Metabolic, obstetric, and neonatal outcomes were compared between groups using appropriate statistical tests.</p> Results <p>Among 37 women with preoperative T2DM, 19 achieved remission and 18 had persistent T2DM after MBS. Patients with persistent diabetes had significantly higher preoperative and pregnancy body mass index, a higher prevalence of hypertension, and less cardiometabolic improvement compared with women with diabetes remission and controls. Women who achieved diabetes remission demonstrated the greatest postoperative weight loss; however, gestational diabetes developed in 52.6% of pregnancies in this group. Hypertensive disorders of pregnancy were most frequent among women with persistent diabetes (33.3%), whereas preeclampsia occurred exclusively in the remission group (21.1%). Cesarean delivery rates were highest in the persistent diabetes group (88%). Neonatal outcomes were largely comparable across groups, although congenital anomalies were more frequent in women with persistent diabetes than in controls (11.1% vs. 2.5%).</p> Conclusion <p>Persistent T2DM confers increased risk of hypertensive disorders and congenital anomalies, while remission improves metabolic health yet does not eliminate susceptibility to gestational diabetes or preeclampsia. </p> Graphical Abstract <p></p>