Background: Pre-pregnancy obesity is strongly associated with certain pregnancy complications and perinatal conditions. Placental structure and function are important for maternal and fetal health both during and after pregnancy. The aim of this study to evaluate the effect of prelabour body mass index on the mode of delivery. Materials and Methods: An hospital-based prospective study involving pregnant women at term (33-37 weeks) admitted to gynaecology ward in district hospital Dholpur, Rajasthan, India during one-year period. A total of 120 cases in the age group of 18-40 years included in the study. Patients were classified into 3 categories based on their first trimester BMI. Category I included normal women (BMI 20- 24.9 kg/m2 ), Category II included overweight women (BMI 25-29.9 kg/m2 ) and detailed history and clinical examination including general physical, obstetrical and systemic examinations. Category III included obese women (BMI >30 kg/m2 ). Data were analysed statistically by Chi-square test of the dependence of variables and a p-value of less than 0.05 was considered as statistically significant. Results: Under anthropometric parameters, the differences in mean age, mean weight, mean height and mean BMI among the three categories women were statistically significant (p<0.001**), In this study, it was observed that overweight and obese women were slightly older and short in stature when compared with women with normal BMI. There was increased incidence of antepartum complications in Category III women as compared to Category II and Category I women. The difference in the onset of labour as well as mode of delivery among the three categories was statistically significant (p<0.05*). Conclusion: As obesity is a modifiable risk factor all attempts should be made to maintain a normal BMI in women of childbearing age. Pre–pregnancy counselling, health programme and appropriate multidisciplinary management should be done.