Obese women without chronic disease are at greater risk of pregnancy complications and poor neonatal outcomes than are normal weight women, according to a study published in Obstetrics & Gynecology.
Sung Soo Kim, Ph.D., of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, and her colleagues, conducted a retrospective cohort study of medical records from the Consortium on Safe Labor, collected from 2002-2008. Singleton pregnancies among U.S. women without prepregnancy diseases were examined for obstetric and neonatal complications based on the prepregnancy body mass index (BMI) of the mother, categorized as either normal weight (18.5-24.9 kg/m2), overweight (25-29.9), obese class I (30-34.9), obese class II (35-39.9), or obese class III (40 or greater). The investigators assessed 112,309 deliveries among 106,552 women (Obstet Gynecol. 2016;128:104-12. doi: 10.1097/AOG.0000000000001465).
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Women with higher prepregnancy BMIs were at greater risk for several types of maternal and neonatal outcomes, according to the findings. For example, the relative risk for gestational diabetes mellitus, compared with women with normal BMIs, was 1.99 for overweight women, 2.94 for obese class I women, 3.97 for obese class II women, and 5.47 for obese class III women.
Similar findings were noted for other maternal outcomes, including higher risks for gestational hypertensive disorders, cesarean delivery, prelabor cesarean delivery, and acute cardiovascular events among women with higher BMIs.
Higher prepregnancy maternal BMI was also associated with increased neonatal risks, including preterm birth at less than 32 weeks of gestation, large for gestational age (LGA) neonates, transient tachypnea, sepsis, and neonatal intensive care unit admission.
The relative risk for LGA neonates, compared with women with normal BMIs, was 1.52 for overweight women, 1.74 for obese class I women, 1.93 for obese class II women, and 2.32 for obese class III women.
In an analysis of a composite variable that included all obstetric and neonatal complications with the exception of interventions, the researchers detected an 18%-47% increased risk of any pregnancy complication among overweight or obese women.
Even obese women who were otherwise healthy at the start of their pregnancy, did not develop pregnancy complications, and gained weight within recommended limits, still had an elevated risk for obstetric and neonatal complications, according to the researchers. “We found increased risks of relatively rare outcomes that other studies could not observe, including maternal acute cardiovascular events and neonatal transient tachypnea, necrotizing enterocolitis, peri- and intraventricular hemorrhage, and retinopathy of prematurity among deliveries to overweight or obese women,” they wrote.
The researchers received support for the work from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors reported having no potential conflicts of interest.