Background: Maternal overweight, obesity, and inappropriate gestational weight gain (GWG) are increasingly recognized as major contributors to adverse pregnancy outcomes worldwide. Elevated pre-pregnancy body mass index (BMI) is associated with gestational diabetes mellitus (GDM), hypertensive disorders, cesarean delivery, fetal overgrowth, and long-term cardiometabolic risks for both mother and child. Regional contemporary data from Bulgaria remain limited. Objective: To evaluate trends in maternal obesity and gestational weight gain among pregnant women in Southeastern Bulgaria between 2021 and 2025, using a regional cohort from Burgas, and to assess associations with maternal and neonatal outcomes. Methods: This retrospective cohort study included 1,176 singleton pregnancies registered for antenatal follow-up at MC Prime Clinic – Dr. Kirovakov Ltd., Burgas, Bulgaria, between January 2021 and December 2025. Women were classified according to World Health Organization BMI categories as underweight, normal weight, overweight, and obese. Gestational weight gain was categorized as below, within, or above Institute of Medicine recommendations. Maternal and neonatal outcomes were analyzed using comparative statistics and multivariable logistic regression. Results: The mean maternal age was 30.8 ± 5.4 years, and the mean pre-pregnancy BMI was 25.1 ± 4.8 kg/m². BMI distribution was: underweight 7.6%, normal weight 49.8%, overweight 27.9%, and obesity 14.7%. Overall, 42.6% of women entered pregnancy overweight or obese. Mean total GWG was 13.2 ± 5.6 kg. Excessive GWG occurred in 39.0% of women, while only 39.6% remained within recommended ranges. Excessive GWG was significantly more common among obese women (52.8%) than among women with normal BMI (34.7%, p<0.001). Compared with women of normal BMI, obese women had significantly higher rates of gestational diabetes mellitus (16.7% vs 5.8%), hypertensive disorders (12.9% vs 4.2%), preeclampsia (8.4% vs 2.1%), cesarean delivery (47.4% vs 28.6%), macrosomia (14.5% vs 6.1%), and preterm birth (10.7% vs 6.9%) (all p<0.05). In multivariable analysis, maternal obesity independently predicted GDM (aOR 2.94, 95% CI 1.82-4.73), preeclampsia (aOR 3.18, 95% CI 1.87-5.39), cesarean delivery (aOR 2.11, 95% CI 1.42-3.14), macrosomia (aOR 2.46, 95% CI 1.51-4.01), and preterm birth (aOR 1.67, 95% CI 1.02-2.74). Conclusions: Maternal obesity and excessive gestational weight gain were highly prevalent among pregnant women in Southeastern Bulgaria during 2021-2025 and were strongly associated with adverse maternal and neonatal outcomes. These findings support the need for preconception counseling, individualized antenatal weight management, and targeted regional public health strategies.

Background: Maternal overweight, obesity, and inappropriate gestational weight gain (GWG) are increasingly recognized as major contributors to adverse pregnancy outcomes worldwide. Elevated pre-pregnancy body mass index (BMI) is associated with gestational diabetes mellitus (GDM), hypertensive disorders, cesarean delivery, fetal overgrowth, and long-term cardiometabolic risks for both mother and child. Regional contemporary data from Bulgaria remain limited. Objective: The objective of this study was to evaluate trends in maternal obesity and gestational weight gain among pregnant women in Southeastern Bulgaria between 2021 and 2025, using a regional cohort from Burgas, and to assess associations with maternal and neonatal outcomes. Methods: This retrospective cohort study included 1176 singleton pregnancies registered for antenatal follow-up at MC Prime Clinic–Dr. Kirovakov Ltd., Burgas, Bulgaria, between January 2021 and December 2025. Women were classified according to World Health Organization BMI categories as underweight, normal weight, overweight, and obese. Gestational weight gain was categorized as below, within, or above Institute of Medicine recommendations. Maternal and neonatal outcomes were analyzed using comparative statistics and multivariable logistic regression. Results: The mean maternal age was 30.8 ± 5.4 years, and the mean pre-pregnancy BMI was 25.1 ± 4.8 kg/m². BMI distribution was: underweight 7.6%, normal weight 49.8%, overweight 27.9%, and obesity 14.7%. Overall, 42.6% of women entered pregnancy overweight or obese. Mean total GWG was 13.2 ± 5.6 kg. Excessive GWG occurred in 39.0% of women, while only 39.6% remained within recommended ranges. Excessive GWG was significantly more common among obese women (52.8%) than among women with normal BMI (34.7%, p < 0.001). Compared with women of normal BMI, obese women had significantly higher rates of gestational diabetes mellitus (16.7% vs. 5.8%), hypertensive disorders (12.9% vs. 4.2%), preeclampsia (8.4% vs. 2.1%), cesarean delivery (47.4% vs. 28.6%), macrosomia (14.5% vs. 6.1%), and preterm birth (10.7% vs. 6.9%) (all p < 0.05). In multivariable analysis, maternal obesity independently predicted GDM (aOR 2.94, 95% CI 1.82–4.73), preeclampsia (aOR 3.18, 95% CI 1.87–5.39), cesarean delivery (aOR 2.11, 95% CI 1.42–3.14), macrosomia (aOR 2.46, 95% CI 1.51–4.01), and preterm birth (aOR 1.67, 95% CI 1.02–2.74). Conclusions: Maternal obesity and excessive gestational weight gain were highly prevalent among pregnant women in Southeastern Bulgaria during 2021–2025 and were strongly associated with adverse maternal and neonatal outcomes. These findings support the need for preconception counseling, individualized antenatal weight management, and targeted regional public health strategies.