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

BACKGROUND: We examined the influence of pre-pregnancy body weight on the rates of attempted and successfully assisted-vaginal delivery. METHODS: 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. RESULTS: 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. CONCLUSION: 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.