Effects of maternal obesity on the success of assisted vaginal delivery in Chinese women

We examined the influence of pre-pregnancy body weight on the rates of attempted and successfully assisted-vaginal delivery.

We used 2008–2016 inpatient records including 3408 women who had singleton gestations and needed operative delivery assistance to conduct a retrospective cohort study. Patients were categorized based on pre-pregnancy BMI (normal weight = 18.5 to less than 25 or obese = 30 or greater). We used logistic regression to estimate odds ratios and 95% confidence intervals of attempted and successful forceps or vacuum-assisted vaginal delivery by body weight adjusted for marital status, age, gestational age, induction of labor, episiotomy, diabetes, and birth weight.

The proportion of women with attempted either vacuum or forceps was lower among women who were obese pre-pregnancy compared to women who were normal weight. Women with excessive gestational weight gain, large for gestational age neonates, and diabetes were less likely to have a vacuum-assisted or forceps-assisted vaginal delivery attempted. Conversely, women who received labor augmentation or induction, used epidural anesthesia, gained inadequate weight, and delivered a small for gestational age infant were more likely to have a vacuum-assisted or forceps-assisted vaginal delivery attempted. Compared to normal weight women, obese women who received forceps-assisted vaginal delivery were more likely to have a successful vaginal delivery.

Women who had normal weight had higher likelihood to attempt assisted vaginal delivery compared to women who had pre-pregnancy obesity. However, when assisted vaginal delivery was attempted, success rates were higher when forceps-assisted delivery was used compared to vacuum-assisted delivery.