Pregnancy outcome according to body mass index in primigravidas: a prospective cohort study

Abstract

Objective: The study aims to evaluate the association between Body Mass Index (BMI), gestational weight gain (GWG) and adverse obstetric outcomes among primigravidas. Material and methods: This was a prospective cohort study conducted at a tertiary University Hospital between June 2015 and May 2017. The study included 480 primigravidas, with singleton pregnancies, who were divided into three groups: women with a healthy weight (BMI: 18.5–24.9 kg/m2) overweight (BMI: 25 – 29.9 kg/m2) and obese (BMI ≥ 30 kg/m2). The primary outcome of the study was the rate of GWG in the participants. Secondary outcomes included the rate of gestational diabetes mellitus (GDM), gestational hypertension, pre-eclampsia, preterm labor (PTL), postdate pregnancy, fetal macrosomia and the rate of birth by cesarean (CB). Results: There were no significant differences between groups regarding the socio-demographic criteria. The rate of GWG was significantly higher in obese women versus average weight women (11.4±1.73 vs. 10.49±1.09, p=0.0001). There was an increased incidence of GDM (p=0.008), gestational hypertension (p=0.001), pre-eclampsia (p=0.0001), PTL (p=0.002), postdate (p=0.0001) and macrosomia (p=0.0001) in women who were obese compared with women with a healthy weight. Additionally, there was an increased incidence of CB with increasing body mass (p=0.0001) Conclusions: Higher BMI in primigravidas is associated with increased GWG and with adverse pregnancy outcomes such as GDM, gestational hypertension, pre-eclampsia, PTL, postdate, fetal macrosomia and cesarean birth.