Association of Pre Pregnancy Body Mass Index and Gestational Weight Gain on Pregnancy Outcomes in Women with Gestational Diabetes: A Retrospective Observational Study

Introduction: The incidence of obesity and gestational diabetes is increasing globally. Gestational diabetes and obesity are known to be independently associated with adverse perinatal outcomes. Gaining excess weight in pregnancy, especially in obese and overweight women appears to increase the risk of maternal and neonatal complications. Aim: To evaluate the association of maternal Body Mass Index (BMI) and Gestational Weight Gain (GWG) with pregnancy outcomes in women with Gestational Diabetes Mellitus (GDM). Materials and Methods: The present retrospective observational study was conducted at Fernandez Hospital, Hyderabad, Telangana, India from January 2017 to December 2019. Singleton pregnancies with gestational diabetes were included. Those booked after first trimester or with pregestational diabetes or hyperthyroidism were excluded. Based on BMI, participants were categorised into lean (<18.5 kg/m2 ), normal (18.5-24.9 kg/m2 ), overweight (25-29.9 kg/m2 ) and obese (>30 kg/m2 ) groups. Based on recommended weight gain for each BMI category, Institute of Medicine (IOM) has laid specific ranges. GWG in each group was divided into inadequate, adequate and excessive weight gain as per these recommendations. Maternal and perinatal outcomes were compared between groups. Regression analysis was carried out and adjusted odds ratio, along with their 95% CI was presented. The p-value <0.05 was considered statistically significant. Statistical Package for the Social Sciences (SPSS) version 25 was used for analysis. Results: Total of 2626 pregnant women were included. Obese and overweight population was 575 (21.9%) and 1095 (41.7%), respectively. Based on GWG, 1042 (39.7%) and 633 (24.1%) had inadequate and excessive weight gain respectively in the entire study population. Both obese and overweight groups had higher caesarean section rates compared to the other two groups. As per regression analysis, obese women had significant adjusted odds ratio {2.32 (95% CI 1.6-3.31)} for gestational hypertension and need for Induction of Labour (IOL) {1.48 (95% CI 1.11-1.97)}. Women with inadequate weight gain had less gestational hypertension {0.68 (95% CI 0.49-0.95)}, need for IOL {1.28 (95% CI 1.001-1.64)}, and less chance for large for gestation age babies {0.67 (95% CI 0.51-0.89)} and more preterm deliveries {1.63 (95% CI 1.20-2.20)} as compared to other groups. In excessive weight gain, odds ratio for large for gestation age babies was found to be significant (p-values <0.001), Adjusted OR {(2.01 (95% CI 1.54-2.64)}. Conclusion: Obese women had higher rate of IOL and caesarean section rate, excess GWG group had higher incidence of large for gestation age neonate.