FREQUENCY OF PRETERM BIRTHS IN OVERWEIGHT AND OBESE PREGNANT WOMEN

Abstract

Background: Preterm birth, defined as delivery before 37 weeks of gestation, is a leading cause of neonatal morbidity and mortality. Globally, approximately 15 million preterm births occur annually, with a significant burden in developing countries. Overweight and obesity in pregnancy have been associated with adverse pregnancy outcomes, including preterm birth, yet the strength of this association varies across populations. In Pakistan, where the preterm birth rate is approximately 14%, understanding the impact of maternal BMI on pregnancy outcomes is critical for targeted interventions and improved maternal and neonatal health.

Objective: This study aimed to determine the frequency of preterm birth among overweight and obese pregnant women and compare the risk between these two BMI categories.

Methods: A cross-sectional study was conducted at the Obstetrics and Gynecology Department, Jinnah Postgraduate Medical Centre (JPMC), Karachi, over six months. A total of 188 pregnant women with a BMI of ≥23.0 kg/m² were enrolled using a non-probability consecutive sampling technique. Women aged 18–40 years with singleton pregnancies and gestational age between 22 and 37 weeks were included, while those with pre-existing medical conditions were excluded. Maternal BMI was calculated, and participants were followed until delivery. Data analysis was performed using SPSS version 26, with the Chi-square test used to compare preterm birth frequencies between BMI groups.

Results: The overall preterm birth rate was 20.2%. Among overweight women (BMI 23.0–24.9 kg/m²), 12.3% experienced preterm birth, while the rate was significantly higher at 25.0% in obese women (BMI ≥25.0 kg/m²) (p=0.032). The mean maternal age was 29.04 ± 4.12 years, with an average gestational age at delivery of 34.15 ± 2.03 weeks.

Conclusion: Maternal obesity is associated with an increased risk of preterm birth. These findings emphasize the need for preconception weight management and targeted antenatal care to reduce preterm birth rates in overweight and obese women.