BACKGROUND World health organization (WHO) declares obesity as a pandemic issue, having high prevalence in females, especially in the childbearing age than in males. Pregnancies complicated by obesity has been identified as early as 1945. Prepregnancy obesity endangers both maternal and fetal well-being. Increasing body mass index (BMI) is associated with increased adverse obstetric and fetal outcomes. Pre-pregnancy obesity and excessive gestational weight gain are parts of maternal obesity during pregnancy. Prenatal maternal obesity and excessive gestational weight gain also improve placental nutrition transfer to the developing foetus and foetal development. The purpose of this study was to evaluate the association between early pregnancy BMI and maternal complications as well as labour outcome. METHODS A prospective observational study comprising 250 antenatal women with singleton uncomplicated pregnancies, booked at Narayan Hospital, Rohtas, South Bihar within the first 12 weeks of gestation were selected for the study. The following inclusion and exclusion criteria were considered. With the help of a predesigned questionnaire, basic information including weight and height was collected in the first check up and BMI was calculated accordingly. BMI was calculated using the formula weight (kg)/height 2 (m2). RESULTS The mean age of mothers was 25.98 ± 3.92 years. Mothers who underwent caesarean section had BMI of 27.36 ± 5.768 and for normal vaginal delivery mothers it was 27.94 ± 6.076, whereas for mother who had undergone forceps delivery, BMI was 30.60 ± 3.864 whereas for other assisted vaginal delivery it was 29.75 ± 7.246. There is mild correlation of BMI of mother to the birth weight of baby. On applying regression analysis, we found mild correlation with R square 0.134. There was no correlation of BMI of mother to the hospital stay of their children. CONCLUSIONS We concluded that however statistically there is no significant association between obesity and numerous maternal and perinatal risks in obese pregnant women but it poses a considerable challenge to the obese patient in successful completion of pregnancy. KEYWORDS Obesity, BMI, Pregnancy Outcome, NICU, Mode of Delivery