Clinicians may underestimate how long a normal second stage of labor should take for women who receive epidurals, and this may result in unnecessary Cesarean deliveries or other interventions, concludes a new study. Current guidelines from the American Congress of Obstetricians and Gynecologists allow for an extra hour of second-stage labor in women with epidurals, prior to interventions. The new study, however, found that the time difference may actually be double, with normal second-stage labor in nulliparous women with epidural taking up to 5.6 hours, compared to 3.3 hours for those without epidural -- a difference of 2 hours and 19 minutes. A similar difference was found in women who have given birth previously. The findings, published in Obstetrics & Gynecology, are based on a retrospective evaluation of 42,268 women who delivered vaginally with normal neonatal outcomes at the University of California at San Francisco between 1976 and 2008. The authors point out that, using current definitions of prolonged labor, nearly one-third of the first-time mothers with epidural would be labeled as having abnormal labor. Read the abstract.