Maternal Obesity and Obstetric Outcomes in a Socially Vulnerable Region Within Brazil's Unified Health System

Introduction  Obesity is a major global public health challenge and a growing concern among women of reproductive age. In Brazil, more than half of these women are overweight, and obesity substantially increases the risk of gestational complications, particularly hypertension (HTN), diabetes, and cesarean delivery. High-risk prenatal care centers within the Brazilian Unified Health System (Sistema Único de Saúde, SUS) play a critical role in managing these conditions, especially in socioeconomically vulnerable regions. This study assessed the association between maternal obesity and childbirth outcomes in a high-risk prenatal care center serving the Jequitinhonha Valley, one of the country's most socially vulnerable areas. Methods  We conducted an institutional, cross-sectional study based on medical records from a State Specialized Care Center and its referral maternity hospital in Diamantina, Minas Gerais, Brazil. Pregnant women receiving high-risk prenatal care between 2021 and 2022 were included if they delivered at the referral hospital. Women with miscarriage, multiple gestation, or delivery elsewhere were excluded. Maternal, obstetric, and neonatal variables were analyzed across BMI categories according to WHO criteria. Statistical analyses included chi-square or Fisher's exact tests, Kruskal-Wallis tests, and multiple linear regression. A significance level of p < 0.05 was adopted. Results  Of 492 women assessed, 285 met the inclusion criteria. Obesity was prevalent in 56.5% of the sample. Obese women had significantly higher rates of cesarean delivery (64%) compared to overweight and eutrophic women (p = 0.046), with obese women being 1.6 times more likely to undergo a cesarean than overweight women and 2.6 times more likely than eutrophic women. Although the need for labor induction did not differ by BMI, indications for induction varied significantly, with hypertensive disorders occurring almost exclusively among overweight and obese women (p = 0.003). Neonatal outcomes, including Apgar scores and birth weight, did not differ significantly between BMI groups. Regression analysis showed gestational age (β = 0.427) and maternal BMI (β = 0.205) as independent predictors of birth weight. NICU admission was modest (1.75%), occurring mainly among premature infants of obese mothers. Conclusion  Maternal obesity was associated with increased obstetric intervention, particularly cesarean delivery and induction for hypertensive disorders. Despite this, neonatal outcomes were comparable across BMI categories, suggesting a potential protective effect of specialized high-risk prenatal care. These findings highlight the importance of strengthening structured, multidisciplinary obstetric services within the SUS, especially in vulnerable regions. Expanding access to reproductive planning and targeted prenatal care may help reduce adverse maternal outcomes. Future longitudinal studies are needed to identify which components of specialized care most effectively mitigate the risks associated with gestational obesity.