EFFECT OF EPIDURAL ANALGESIA ON FUNDAL DOMINANCE DURING SPONTANEOUS ACTIVE-PHASE NULLIPAROUS LABOR

Background: The purpose of this investigation was to determine if epid ural analgesia, established during active phase labor, results in elim ination or reversal of fundal dominance (lower uterine segment pressur e equal to or greater than fundal pressure). Methods: Upper and lower uterine segment intrauterine pressures were prospectively evaluated fo r 50 min before and 50 min after epidural analgesia using 0.25% bupiva caine in 11 nulliparous women in spontaneous active labor. A total of 958 contractions were evaluated. Results: No significant differences w ere found in the number of contractions In the interval before epidura l analgesia compared to after epidural analgesia. Significantly greate r pressure readings were recorded in the upper segment than in the low er segment (consistent with fundal dominance) both before and after ep idural analgesia (P < 0.01). in addition, fundal dominance increased a fter 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.