Pre-pregnancy body mass index and gestational weight gain and their effects on pregnancy and birth outcomes: a cohort study in West Sumatra, Indonesia

Background: Indonesia has a considerably high incidence of maternal and infant mortality. The country has however been experiencing a social and economic transition, influencing its general population demographics and nutritional status including the state of health and nutrition of pregnant women. This study aimed to explore body mass index (BMI) and gestational weight gain (GWG), and their relationship with pregnancy outcomes in a sample of Indonesian pregnant women. Methods: This observational cohort study included a total of 607 pregnant women who were recruited in 2010 from maternity clinics in Western Sumatra, Indonesia. Multiple logistic and regression analyses were undertaken to compare pregnancy and birth outcomes for different BMI and GWG, using normal weight women and women with a recommended weight gain as the referent groups. Results: The prevalence of underweight (BMI < 18.5 kg/m2) in pregnancy was high at 20.1%; while 21.7% of women were overweight (BMI: 23.0–27.4 kg/m2) and 5.3% obese (BMI ≥ 27.5 kg/m2) using the Asian BMI classifications. The incidence of overweight (BMI: 25.0–29.9 kg/m2) and obese (BMI ≥ 30.0 kg/m2) according to the international BMI classifications were 13.5% and 1.1% respectively. The majority of women gained inadequate weight in pregnancy compared to the Institute of Medicine (IOM)recommendations, especially those who had a normal BMI. Birthweight adjusted mean difference aMD (95% confidence interval) 205 (46,365) and the odds of macrosomia adjusted odds ratio aOR 13.46 (2.32–77.99) significantly increased in obese women compared to those with a normal BMI. Birthweight aMD -139 (−215, −64) significantly decreased in women with inadequate GWG compared to those with recommended GWG, while SGA aOR 5.44 (1.36, 21.77) and prematurity aOR 3.55 (1.23, 10.21) increased. Conclusions: Low nutritional status and inadequate GWG remain a cause for concern in these women. The higher odds of macrosomia with increasing maternal BMI and higher odds of prematurity and small for gestational age infants with inadequate weight gain also require attention. Research and practice recommendations: Urgent attention is required by researchers, policy makers and decision makers to facilitate development of culturally sensitive interventions to enhance nutritional status and health of mothers and babies, in an area known for its high incidence of maternal and neonatal mortality. Keywords: Maternal BMI, Gestational weight gain, Pregnancy outcomes, Birthweight, Indonesia, Cohort study