Prepregnancy body mass index (BMI) was strongly related to infant mortality, neonatal and postneonatal, even after controlling for multiple risks. This according to a cohort study using data from 38 states and the District of Columbia with the BMI measure, including 6,419,836 singleton births and 36,691 infant deaths. The study concluded:

• The odds ratio for an infant death rose from 1.32 for mothers in the obese I category to 1.73 for obese III with normal prepregnancy weight as a reference.

• Higher BMI was related to higher rates of both neonatal and postneonatal mortality.

• Adjusted OR for the risk of an infant death among singleton, term, vertex births for those gaining less than the recommended weight was 1.07 and 1.04 for those gaining more than recommended.

Citation: Declercq E, MacDorman M, Cabral H, Stotland N. Prepregnancy body mass index and infant mortality in 38 US states, 2012-2013. [Published online ahead of print January 7, 2016]. Obstet Gynecol. doi: 10.1097/AOG.0000000000001241.

Commentary: The rate of obesity among adolescents and young adults has tripled in the last 20 years. The downstream effects of this are numerous, including an increased risk of hypertension, diabetes, arthritis and heart disease. This study adds to the known negative consequences of obesity, showing a 30% to 70% increase in the risk of infant mortality with prepregnancy maternal obesity. —Neil Skolnik, MD