550: The impact of second and third trimester rate of gestational weight gain on maternal and neonatal outcomes

Abstract

In 2009, the Institute of Medicine released revised gestational weight gain (GWG) guidelines. We sought to determine the impact of second and third trimester rate of GWG on maternal and neonatal outcomes in each body mass index (BMI) class using the revised recommendations. This is a retrospective, population-based cohort study of all singleton live births in the Finger Lakes Region of New York between 1/2004 and 12/2008. Women were grouped according to pre-pregnancy BMI as underweight, normal weight, overweight, and obese classes I, II, and III. Rates of second/third trimester GWG were calculated. Women were then classified as having less than, within, or greater than recommended rates of gain. Maternal and neonatal outcomes were assessed for all BMI groups and for rate of GWG groups within each BMI class. Analysis consisted of chi square, ANOVA, and logistic regression,with p<0.01 defined as statistically significant. Of 73,977 women meeting inclusion criteria, 4% were underweight, 48% normal weight, 24% overweight, and 24% obese (13% class I, 6% class II, and 5% class III). Compared to normal weight, underweight women had lower adjusted odds ratios (aOR) of cesarean delivery (CD) and induction of labor (IOL) (aOR 0.81 - 0.83). For all BMI groups above normal weight, the aORs were increased for CD (1.40-3.18), gestational diabetes (1.93-6.33), and IOL (1.22-1.59), and decreased for operative vaginal delivery (0.76-0.95). After controlling for potential confounding variables, less-than-recommended rates of 2nd/3rd trimester GWG were associated with increased aORs for SGA in all BMI groups except obese class II and III (1.55-2.32). Greater-than-recommended rates of GWG were associated with increased aORs of LGA in all BMI groups (1.56-2.46), and increased aORs of CD in all BMI groups (1.36-1.45) except underweight and obese class III. In our population, both increasing BMI and 2nd/3rd trimester GWG rates outside recommended ranges are associated with adverse maternal and neonatal outcomes.