A REEVALUATION OF THE ASSOCIATION BETWEEN INSTRUMENT DELIVERY AND EPIDURAL ANALGESIA

Background and objectives. Over 100 papers in the medical literature s uggest pro or con that epidural analgesia is associated with an increa se in the incidence of instrument delivery. This two-component study w as performed to evaluate the influence of epidural labor analgesia on the incidence of instrument delivery. Methods. Component 1 was a retro spective analysis of the medical records of 14,804 mothers having a va ginal delivery before and after implementation of an active epidural s ervice. Component 2 was a case control study designed to determine fac tors, in addition to epidural analgesia, associated with an increase i n instrument delivery. In component 2 11 factors describing maternal, fetal, anesthetic, and obstetric factors were analyzed for each of 609 consecutive patients having an instrument delivery and 246 controls h aving a spontaneous vaginal delivery. Results. In component 1, despite a tenfold increase in the use of epidural analgesia, there was a simi lar association between epidural use and instrument delivery in both t ime periods. Additionally, the epidural-forceps association was twice as strong for parous patients as for nulliparous patients (odds-ratios 9.74 and 4.52, respectively). In component 2, five factors were signi ficantly (P > .0001) associated with instrument delivery conclusions. Conclusions. While epidural analgesia was one factor, the others were gestational age > 41 weeks, a second stage of labor > 2 hours, an occi put posterior or transverse fetal position, and previous cesarean sect ion. These four factors are individually and independently associated with an increase in the incidence of instrument delivery independent o f epidural use.