Objective: To compare severe short-term maternal and neonatal morbidity associated with midpelvic and low pelvic attempted operative vaginal delivery.
Methods: Prospective study of 2,138 women with live singleton term fetuses in vertex presentation who underwent an attempted operative vaginal delivery in a tertiary care university hospital. We used multivariate logistic regression and propensity score methods to compare outcomes associated with midpelvic and low pelvic delivery. Severe maternal morbidity was defined as third- or fourth-degree perineal laceration, perineal hematoma, cervical laceration, extended uterine incision for cesarean delivery, postpartum hemorrhage greater than 1,500 mL, surgical hemostatic procedures, uterine artery embolization, blood transfusion, infection, thromboembolic events, admission to the intensive care unit, and maternal death; severe neonatal morbidity was defined as 5-minute Apgar score less than 7, umbilical artery pH less than 7.00, need for resuscitation or intubation, neonatal trauma, intraventricular hemorrhage greater than grade 2, neonatal intensive care unit admission for more than 24 hours, convulsions, sepsis, and neonatal death.
Results: From December 2008 through October 2013 there were 2,138 attempted operative vaginal deliveries; 18.3% (n=391) were midpelvic, 72.5% (n=1,550) low, and 9.2% (n=197) outlet. Severe maternal morbidity occurred in 10.2% (n=40) of midpelvic, 7.8% (n=121) of low, and 6.6% (n=13) of outlet attempts (P=.21); and severe neonatal morbidity in 15.1% (n=59), 10.2% (n=158), and 10.7% (n=21) (P=.02), respectively. Multivariable logistic regression analysis found no significant difference between midpelvic and low attempted operative vaginal delivery for either composite severe maternal (adjusted odds ratio [OR] 1.01, 95% confidence interval [CI] 0.66-1.55) or neonatal morbidity (adjusted OR 1.25, 95% CI 0.84-1.86). Similarly, propensity score matching found no significant difference between midpelvic and low operative vaginal delivery for either severe maternal (adjusted OR 0.69, 95% CI 0.39-1.22) or neonatal morbidity (adjusted OR 0.88, 95% CI 0.53-1.45).
Conclusion: In singleton term pregnancies, midpelvic attempted operative vaginal delivery compared with low pelvic attempted operative vaginal delivery was not associated with an increase in severe short-term maternal or neonatal morbidity.
Level of evidence: II.