Comparison of WHO and Indian Consensus BMI Criteria for Predicting Maternal Outcomes in a North Indian Population

Introduction: Gestational weight and maternal adiposity are important determinants of obstetric outcomes. This study evaluates the utility of Indian consensus BMI criteria, in combination with waist circumference, for predicting adverse maternal outcomes in a North Indian population. The aim of this study was to assess the association of maternal BMI and waist circumference with maternal outcomes in North Indian pregnant women, using the WHO and Indian consensus BMI criteria for comparison. Methods: In this prospective observational study at a tertiary care hospital in North India, 943 pregnant women in their first trimester (8–13 weeks gestation) were enrolled. Participants were classified according to WHO and Indian consensus BMI criteria, and waist circumference was measured. Maternal outcomes—including mode of delivery, labour onset, and live birth—were recorded. Associations between anthropometric measures and outcomes were analyzed using chi-square tests. Results: Using WHO criteria, 54.7% of participants had normal BMI and 27.8% were overweight, whereas under the Indian consensus definition, 41.4% were normal and 37.2% were obese. Waist circumference exceeded 80 cm in 66.8% of participants. BMI was significantly associated with mode of delivery (P<0.001), with higher BMI linked to increased rates of caesarean section. Using WHO BMI classification, LSCS rates were 26.5% (13/49) in underweight, 38.5% (155/403) in normal BMI, 47.5% (97/204) in overweight, 52.4% (33/63) in obese, and 90.9% (10/11) in morbidly obese women. A similar increasing trend was observed using the Indian consensus BMI classification, with LSCS rates of 27.3% (9/33) in underweight, 35.5% (109/307) in normal BMI, 44.6% (50/112) in overweight, and 50.4% (140/278) in obese women. When BMI was categorized using the Indian consensus definition, a higher proportion of women in the overweight and obese categories underwent induced labour compared to those with normal BMI. Specifically, induced labour was observed in 16.0% (13/60) of overweight and 22.1% (30/136) of obese women, compared to 16.0% (31/194) in the normal BMI group. This distribution resulted in a statistically significant association between BMI category and onset of labour (χ² test, P=0.001). In contrast, the association was not statistically significant when BMI was classified using WHO criteria (P=0.072). Conclusion: Maternal BMI classified using Indian consensus criteria more accurately predicts labour onset and mode of delivery than WHO BMI in this North Indian population. Use of region-specific BMI cut-offs may enhance risk stratification and guide obstetric care in Indian settings