ASPPH logo


Member Research & Reports

Member Research & Reports

BU: Pre-Pregnancy Obesity Increases Likelihood of Primary Cesareans

Pre-pregnancy obesity increases the likelihood that women with low-risk pregnancies who have not had prior cesarean deliveries will have C-sections, even after controlling for social and medical risk factors, a new study led by a Boston University School of Public Health (BUSPH) researcher has found.

The study, published online in the journal Birth, offers the strongest evidence yet identifying pre-pregnancy obesity as an independent risk factor for cesarean delivery. The research team analyzed 2012 birth certificate data for more than 2.2 million new mothers, in 38 states, who had not had prior cesareans. Overall, 46.4 percent of mothers had BMIs (body mass index) in the overweight (25.1 percent) or obese (21.3 percent) categories.

Rates of cesareans were 1.6 to two times higher for obese women than for those in the normal weight category, the study found, with higher rates among the very obese. The sample was limited to women who had a singleton birth at full term.

“The likelihood of a primary cesarean increased consistently across categories of obesity in a population of low-risk women who would otherwise be likely candidates for a vaginal birth, even after controlling for demographic and medical risk factors,” said lead author Dr. Eugene Declercq, professor of community health sciences.

To read more about the study, go to: