Association between the number of pulls and adverse neonatal/maternal outcomes in vacuum-assisted delivery

To determine the association between the number of pulls during vacuum-assisted deliver and neonatal and maternal complications.

This was a single-center observational study using a cohort of pregnancies who underwent vacuum-assisted delivery from 2013 to 2020. We excluded pregnancies transitioning to cesarean section after a failed attempt at vacuum-assisted delivery. The number of pulls to deliver the neonate was categorized into 1, 2, 3, and ≥4 pulls. We used logistic regression models to investigate the association between the number of pulls and neonatal intensive care unit (NICU) admission and maternal composite outcome (severe perineal laceration, cervical laceration, transfusion, and postpartum hemorrhage ≥500 mL).

We extracted 480 vacuum-assisted deliveries among 7,321 vaginal deliveries. The proportion of pregnancies receiving 1, 2, 3, or ≥4 pulls were 51.9, 28.3, 10.8, and 9.0%, respectively. The crude prevalence of NICU admission with 1, 2, 3, and ≥4 pulls were 10.8, 16.2, 15.4, and 27.9%, respectively. The prevalence of NICU admission, amount of postpartum hemorrhage, and postpartum hemorrhage ≥500 mL were significantly different between the four groups. Multivariable logistic regression analysis found the prevalence of NICU admission in the ≥4 pulls group was significantly higher compared with the 1 pull group (adjusted odds ratio, 3.3; 95% confidence interval, 1.4-7.8). In contrast, maternal complications were not significantly associated with the number of pulls.

Vacuum-assisted delivery with four or more pulls was significantly associated with an increased risk of NICU admission. However, the number of pulls was not associated with maternal complications.