Effect of epidural analgesia on fundal dominance during spontaneous active-phase nulliparous labor

Background: The purpose of this investigation was to determine if epidural analgesia, established during active phase labor, results in elimination or reversal of fundal dominance (lower uterine segment pressure equal to or greater than fundal pressure). Methods: Upper and lower uterine segment intrauterine pressures were prospectively evaluated for 50 min before and 50 min after epidural analgesia using 0.25% bupivacaine in 11 nulliparous women in spontaneous active labor. A total of 958 contractions were evaluated. Results: No significant differences were found in the number of contractions in the interval before epidural analgesia compared to after epidural analgesia. Significantly greater pressure readings were recorded in the upper segment than in the lower segment (consistent with fundal dominance) both before and after epidural analgesia (P < 0.01). In addition, fundal dominance increased after epidural analgesia when compared to the preanalgesia period (P < 0.01). Conclusions: Fundal dominance is present both before and after active phase epidural analgesia and is increased during the immediate 50-min postanalgesia period.