Maternal and Neonatal Outcomes among Obese Women with Gestational Weight Gain above the New Institute of Medicine (IOM) Recommendations

Gestational weight gain is important for optimal maternal and neonatal outcomes. New Institute of Medicine (IOM) recommendations for gestational weight gain define obesity as body mass index (BMI) ≥30 and do not differentiate between maternal obesity classes. The recommended weight gain is 11-20 lbs. for obese women. The purpose of this study is to document prevalence of maternal obesity, excess gestational weight gain, and negative maternal and neonatal outcomes prior to 2009 IOM recommendations for gestational weight gain. This was a retrospective cohort study using Texas birth/infant death certificate data for 2005 through 2009, inclusive. The study population included 419,028 women. Those with excess (>20 lbs.) gestational weight gain were compared with those who gained the recommended 11-20 lbs. Compared to the recommended weight-gain group, women in the excessive weight-gain group had lower percentage of gestational diabetes, across three obesity classes. Women with excessive weight gain had higher percentage of pre-eclampsia and Cesarean delivery (C-section) than women in the recommended weight-gain group. Babies of women with excessive weight gain in Obesity Class III had higher percentages of Neonatal Intensive Care Unit (NICU) admission, assisted ventilation >6 hours, surfactant therapy, and antibiotics for suspected sepsis than babies of women in Obesity Class III, gaining within the IOM recommendation. Findings suggest that the relationships between maternal obesity classification, gestational weight gain, and maternal and neonatal outcomes are complex. Further evidence is needed to make recommendations on gestational weight gain for obese women, stratified by the severity of obesity.