The Change Of Duration Of Labor In The Past Twenty Years:a Meta Analysis

ObjectiveTo evaluate the duration of labor of normal nulliparous in the past20years compared with Friedman labor curve.MethodsFrom1990to2011, We searched PubMed, EMBASE, Cochrane Library, CINK, VIP and Wanfang database, and references of the included studies. Studies involved observational research of the duration of labor in singleton vertex presentation nulliparous women. Data were evaluated and extracted by two reviewers independently with designed extraction form. The Cochrane Collaboration’s RevMan5.1software was used for meta-analyses.ResultsFinally, eleven literatures involving4534nulliparous women, which were eligible for the criteria to investigating the labor duration. Meta-analysis showed that the length of active phase was significant different between normal nulliparous women in the past20years and Friedman labor curve(P=0.01, WMD=1.61,95%CI:0.38-2.83), and significant differences also were found in the part of second stage duration (P=0.0006, WMD=-0.20,95%CI:-0.31-0.09).ConcusionsCompared with Friedman labor curve, active phase length of normal nulliparous in the past20years was significantly longer and second stage length was shorter. Reassessing labor curve of normal nulliparous is required for more scientific guide managing labor and reduce unnecessary intervention.