Re-evaluation of the definition of prolonged labor

日本妇产科学会将延长分娩定义为初产妇分娩超过30小时，经产妇超过15小时。在本研究中，这一定义分别对应于660名初产妇和641名经产妇的产程第98和第97个百分位数。初产妇产程第90百分位数为20小时，经产妇为10小时。经Mann-Whitney U检验，初产妇分娩时间>20小时和经产妇分娩时间>10小时，5min阿普加评分显著降低(P=0.013，P=0.035)。这些发现表明，延长分娩的定义可能是初产妇的分娩时间超过20小时，经产妇超过10小时。

Japan Society of Obstetrics and Gynecology defines prolonged labor as labor more than 30 hours in primiparas and 15 hours in multiparas. Such a definition corresponds to 98th percentile and 97th percentile in duration of labor in 660 primiparas and 641 multiparas in present study, respectively. The 90th percentile of durations of labor was 20 hours in primiparas and 10 hours in multiparas. Using a Mann-Whitney U test, significant decreases in 5 minute Apgar score were found in primiparas with labor more than 20 hours and in multiparas with labor more than 10hours (P=0.013, P=0.035, respectively). These findings suggest that prolonged labor may be defined as labor more than 20 hours in primiparas and 10 hours in multiparas.