Though women who have had a cesarean section can often deliver vaginally with their next pregnancy, the odds of success may be lower for overweight and obese women, according to researchers led Dr. Peter Baumann of Wayne State University . Their study of nearly 8,600 pregnant women with a history of C-section found that the likelihood of a successful vaginal delivery dipped as a woman's weight climbed. Overweight and obese women were more likely than their lighter peers to require a C-section after an attempt at vaginal delivery failed.