Vacuum-assisted delivery more likely to fail than forceps

Cases of operative vaginal delivery that use vacuum extraction are more likely to fail than those using forceps, and in most instances of failed vacuum extraction, the practitioner then attempts a forceps delivery, according to research presented in the September issue of the American Journal of Obstetrics and Gynecology.

Avi Ben-Haroush, MD, of the Sackler Faculty of Medicine at Tel Aviv University in Israel, and colleagues conducted a retrospective cohort study of 5,120 women undergoing an attempted operative vaginal delivery at a facility over a 13-year period. Eighty-four percent of these were vacuum extraction, and the remainder were forceps delivery.

In 8.6% of cases, the procedure failed; failure occurred with vacuum extraction 10% of the time, compared with 1.3% with forceps. When vacuum extraction didn't work, practitioners typically attempted the delivery with forceps, which then failed in 3.5% of the cases. Aside from using forceps, other factors associated with a lower risk of failure were the use of epidural (OR, 0.4) or IV opiate analgesia (OR, 0.2). Factors associated with higher risk of failure were persistent occiput posterior position (OR, 2.2) and birthweight exceeding 4 kg (OR, 2.8).

"Operative techniques are associated with a greater tendency for birth injury than spontaneous delivery," the authors write. "Fetal weight and head position should be evaluated carefully before operative vaginal delivery, and the use of analgesia should be encouraged."

Ben-Haroush A, Melamed N, Kaplan B, et al. Predictors of failed operative vaginal delivery: a single-center experience. Am J Obstet Gynecol. 2007;197:308.e1-308.e5.