The mutual effect of pregestational body mass index, maternal hyperglycemia and gestational weight gain on adverse pregnancy outcomes

Objective: To investigate the mutual effect of obesity, gestational diabetes (GDM) and gestational weight gain (GWG) on adverse pregnancy outcomes. Methods: Charts of patients who delivered in our hospital between June 2001 and June 2006 singleton, live births > 24 weeks gestation were reviewed. Univariate and multivariate logistic regression were used to assess pregnancy outcomes defined as large for gestational age (LGA), primary cesarean section (PCS) and a composite outcome of LGA and/or PCS. Results: A total of 8595 women were included. Frequency of composite outcome increased with increasing body mass index (BMI), increasing hyperglycemia and above-recommended GWG. In the multivariate logistic regression analysis compared to women with normal BMI, odds ratio (OR) for composite outcome was 1.23 (95% confidence interval [CI] 1.06-1.44) in overweight women, OR = 1.86 (1.51-2.31) in obese women and in severe obesity OR = 2.97 (2.15-4.11). Compared to normoglycemic women, odds for composite outcome in women with abnormal glucose challenge test OR = 1.46 (1.20-1.79), impaired glucose tolerance OR = 1.65 (1.14-2.4) and GDM OR = 1.56 (1.16-2.10). Women with GWG above recommended had OR = 1.58, (1.37-1.81) for composite outcome. Conclusions: Higher pregestational BMI, maternal hyperglycemia and above-recommended GWG independently contribute to adverse pregnancy outcomes. Furthermore, there is mutual effect between these three factors and adverse outcomes. Appropriate pregestational weight and adequate GWG might reduce risk of adverse pregnancy outcomes.