Obesity is becoming a global health care problem and an increasing number of obese female patients are getting pregnant. Aim of our study was to know the prevalence of obesity in nulliparous women and its impact on pregnancy as well as fetus. Patients and Methods: All nulliparous women with single pregnancy and gestational age of 37 weeks and above were included in the study. Primigradvida with multiple pregnancies, fetal abnormalities, and gestational age less than 37 weeks were excluded. Patients were divided into normal, overweight and obese group according to their prepragnancy body mass index (BMI). Results: Total 2243 nulliparous women were included in the study, majority (56.8%) of patients were in the normal BMI group and only 24.8% were obese. But a significantly higher number of obese nulliparous women were in the age group of 18 to 29 years (P < 0.05). Comorbidities were significantly higher in obese primigravida. The incidence of gestational diabetes and pregnancy induced hypertension was significantly higher (P < 0.05) in obese nulliparous women. Overweight and obese nulliparous patients required significantly higher emergency caesarean section and assisted vaginal deliveries compared to the normal BMI nulliparous women (P < 0.03). Conclusion: Maternal obesity leads to prepartum, peripartum as well as fetal complication. Obese pregnant patients had a significant risk of developing gestational diabetes and pregnancy induced hypertension. In these patients the prevalence of assisted vaginal and cesarean deliveries is significantly high.