Background <p>Metabolic bariatric surgery (MBS) is recommended for patients with a body mass index &gt; 40&#xa0;kg/m² to reduce the risk of diabetes, hypertension, and other obesity-related comorbidities. However, pregnancy following MBS increases the risk of adverse neonatal and maternal outcomes. This study aimed to investigate the association between previous MBS and adverse maternal and neonatal outcomes.</p> Methods <p>This prospective cohort study recruited 209 pregnant women between July 2021 and November 2022 from a tertiary maternity hospital in Abu Dhabi, United Arab Emirates. Among them, 99 had a history of metabolic and bariatric surgery (MBS), while 110 had no prior MBS. Primary outcomes were gestational weight gain (GWG) and neonatal birth weight.</p> Results <p>The mean gestational weight gain among women without MBS was 11.3 ± 5.73&#xa0;kg compared with 7.9 ± 5.61&#xa0;kg in women with MBS (<i>p</i> &lt; 0.001). Chi-Square analysis revealed a significant association between low birth weight and preterm outcomes with MBS, with significantly higher prevalence of both low birth weight and preterm in the MBS group compared with the non-MBS group. Logistic regression analysis confirmed the higher risk for both low birth weight and preterm in the MBS group. Moreover, metabolic bariatric surgery was not associated with GWG, however, parity was positively associated with GWG.</p> Conclusions <p>Metabolic bariatric surgery was associated with adverse neonatal outcomes without apparent adverse maternal outcomes.</p>