Association of gestational weight gain and pre-pregnancy body mass index with adverse pregnancy outcome

OBJECTIVE: To determine the association between gestation weight gain (GWG) and adverse pregnancy outcome in a Pakistani population. STUDY DESIGN: Analytical study. PLACE AND DURATION OF STUDY: The Aga Khan University, Karachi, from February 2003 to 2007. METHODOLOGY: This study used secondary data of 4,735 women from a large cohort study on fetal growth. Pre-pregnancy BMI was categorized according to the recommendations from the institute of medicine (IOM, 2009) and gestation weight gain (GWG) was noted. Chi-square test was used to find the association of GWG and pre-pregnancy BMI with low birth weight (LBW), preterm delivery, large for gestational age (LGA), and caesarean section. Logistic regression analysis was performed to control for confounders like age, parity, working status and ethnicity. RESULTS: The prevalence of LBW decreased with increasing BMI. GWG of the population was noted as 8.5 kg. LBW was observed to have an inverse relationship with GWG. Women below the age of 19 were twice more likely to have LBW than above 35 years of age. Weight gain above the recommended range were twice more likely to have large for dates.Overweight women were 1.5 times more likely to deliver preterm whereas obese women were 1.4 times more likely to undergo caesarean section than women with normal BMI. CONCLUSION: The optimal weight gain was estimated to be 8.5 kg to prevent low birth weight in our population. Obese women are more likely to have LGA, caesarean sections and pre-term deliveries.