Additionally, for women who had not yet given birth (nulliparous), the cesarean delivery rate was 20.7 percent for the control group, compared with 33.8 percent for obese women, and 47.4 percent -- three times more likely -- for morbidly obese women.
"The increased risk of cesarean section is concerning because complications related to surgery are more frequent in obese women," says Dr Mary D'Alton, gynecologist and obstetrician-in-chief at NewYork-Presbyterian Hospital/Columbia and chair of Obstetrics and Gynecology and director of Maternal Fetal Medicine at Columbia University College of Physicians & Surgeons. "As a result of this study, obese and morbidly obese patients now have access to more precise information about their health risks during pregnancy" says Dr Fergal Malone, director of Ultrasound and associate professor in the Department of Obstetrics of Gynecology at Columbia University College of Physicians & Surgeons.
Risks associated with hypertension and preeclampsia include seizures during labor, intracranial bleeding, liver rupture, bleeding, poor fetal growth and stillbirth. Gestational diabetes is associated with risk of a fetus that is too large to easily fit through the birth canal, risk of a fetus that gets stuck during delivery (shoulder dystocia), and risk that the newborn baby will have very low blood sugar (hypoglycemia) -- which, if unrecognized, can lead to newborn seizures. A fetus size greater than 4,000 grams is also a risk for shoulder dystocia.
The data was obtained from patients over a short time period -- 1999 to 2002 -- and therefore represents an accurate snapshot of the state of this issue in contemporary practice, says Dr D'Alton. The study, which followed women enrolled in the multi-center First and Second Trimester Evaluation of Risk (FASTER) trial, included 13,752 control patients, 1,473 obese patients, and 877 morbidly obese patients. Subjects were divided into three groups: body mass index (BMI) of less than 30 (control), 30 to 34.9 (obese), and 35 or greater (morbidly obese) -- criteria defined by the Institute of Medicine. Groups were compared using univariate and multivariable logistic regression analyses.
Since 1991, there has been a 50 percent to 70 percent increase in the rate of obesity in adults of reproductive age. Approximately one-quarter to one-third of the US population is obese. Obesity has long-term health implications such as uterine cancer, diabetes mellitus and heart disease.