Body mass index on outcomes of nulliparous singleton pregnancies in Brunei Darussalam

Body mass index on outcomes of nulliparous singleton pregnancies in Brunei Darussalam

Introduction: Studies have shown that both overweight and underweight women are more likely to have adverse pregnancy outcomes compared to those with normal body weight. This study assessed the impact of body mass index (BMI) on pregnancy outcomes among primigravid women who delivered at a tertiary hospital.
Materials and Methods: All nulliparous women delivering singleton babies at RIPAS Hospital (1st October 2009 to 30th September 2010, N=1,290) were included. BMI was classified based on the World Health Organisation classification. For analyses, the BMI groups were categorised into three groups; Low (<20.0 kg/m2), Normal (20.1 to 24.9) and High (>25.0). The relative risk (RR) for Gestational Hypertension (GHT), Gestational Diabetes Mellitus (GDM), assisted delivery and induction of labour (IOL) were calculated for the different BMI groups. Results: Overall, 40.4%, 19.8% and 39.8% were categorised as Normal, Low and High BMI respectively. Hypertension (5.8%) and diabetes mellitus (2%) were more common in the High BMI group, while anaemia was common in the Low (34%) and Normal groups (23.8%). The High group were more likely to have GHT and GDM, IOL and likely to need assisted delivery (all p<0.001). Low BMI group had a lower prevalence of GHT and GDM, higher preterm labour, small for gestational age (SGA) babies, and more normal vaginal delivery (all p<0.05). There were no significant differences in admission to special care baby unit and rates of stillbirth or early neonatal death between the different groups. Multivariate analyses (controlled for maternal age and smoking) showed higher risk for GHT (RR=2.6, 95% CI=1.2-5.4) in the Normal and High BMI groups (RR=3.7, 95% CI=1.8-7.5), and GDM among the high BMI group (RR=2.6, 95% CI=1.1-6.1). The risk for assisted delivery was also higher (RR 2.0, 95% CI=1.4-2.9) compared to the Normal and High BMI group (RR 1.3, 95% CI=0.9-1.6) and IOL was higher among normal BMI (RR 1.5, 95% CI=1.0-2.2) and High BMI (2.7, 95% CI = 1.9-4.0) groups.
Conclusions: Maternal BMI was strongly associated with pregnancy complications and outcomes. There is a need for an effective programme to increase awareness of the importance of achieving normal BMI for a healthy pregnancy.

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