Fetal Growth Abnormalities in Overweight and Obese Pregnant Women: A Study Among Bulgarian Pregnant Women

Abstract A small for gestational age (SGA) newborn is a clinical finding during pregnancy resulting from various underlying conditions, such as placental pathology, preeclampsia, gestational diabetes, and maternal obesity. SGA is usually suspected when the fetal weight falls below the 10th centile for gestational age and must be distinguished from fetal growth restriction. Aims To evaluate the influence of prepregnancy BMI on the prevalence of SGA and fetal macrosomia at term in singleton pregnancies within a non-selected population of Bulgarian women. Materials and Methods A total of 199 overweight (BMI 25-29.9 kg/m²) and 198 obese (BMI ≥ 30 kg/m²) women were compared with a control group of 459 women with normal prepregnancy BMI (18.5-24.9 kg/m²). Birthweight categories included: normal for gestational age (10th-90th percentile), low for gestational age (below 10th per-centile), and large for gestational age (above 90th percentile). SGA was further classified into moderate (3rd-10th percentile) and severe (below 3rd percentile). Results Results indicated a statistically significant lower percentage of normal birth weight in the overweight group (76.88%) compared to the control group (82.57%, p = 0.044). Overweight women had a higher incidence of large for gestational age newborns (17.59%) compared to the control group (10%, p = 0.03). No significant differences were found in low birthweight or moderate SGA between groups. However, severe SGA was significantly less common in the overweight group (1%) compared to the obese group (3.54%, p = 0.0045). Macrosomia (birth weight ≥ 4000 g) was more prevalent in overweight women (10.3%) than in those with a normal BMI (5.82%, p = 0.037). Relative risk analysis showed increased risks for large for gestational age and macrosomia in overweight and obese women. Conclusions The study emphasizes the importance of targeted interventions to control and regulate maternal weight to minimize the risk of adverse fetal and neonatal outcomes.