Curve of labor duration in 2 140 nulliparous women / 中华围产医学杂志

ABSTRACT

Objective To analyze labor duration in nulliparous women and discuss the change about curve of labor duration. Methods Two thousand, one hundred and forty nulliparous, full-term pregnant, singleton, cephalic presentation and vaginal delivery women who delivered at Peking University First Hospital were included. There were 1 300 cases between January 1, and December 31, 2009, while 840 cases between January 1, and May 31, 2013. A retrospective study was conducted. Data on maternal age, gestational age at delivery, body mass index at delivery, newborn weight, time of labor initiation, cervical dilatation and the amount of bleeding within the first 24 h after delivery were recorded. Data were compared by t test and χ2 test. The median time span corresponding to one-centimeter-increase in cervical dilatation was calculated. Results (1)Compared with data from 2009, the maternal age [(29.0±3.0) vs (29.6±2.8) years, t=4.77], incidence of postpartum hemorrhage [1.8%(24/1 300) vs 4.3%(36/840),χ2=11.17], proportion of induced labor [37.3%(485/1 300) vs 64.0%(538/840),χ2=146.23] and proportion of analgesia during labor [54.2%(705/1 300) vs 61.5% (517/840), χ2=11.15] were all higher in 2013 (all P<0.01). (2)The median (minimum–maximum) time span corresponding to a one-centimeter-increase in cervical dilatation was 3-4 cm which corresponded to 2.2 h(0.8-4.3 h), 4-5 cm which corresponded to 1.9 h(0.6-4.0 h), 5-6 cm which corresponded to 1.8 h(0.5-4.0 h), 6-7 cm which corresponded to 1.6 h(0.5-2.0 h), 7-8 cm which corresponded to 1.8 h(0.8-2.0 h), 8-9 cm which corresponded to 1.3 h(0.2-2.5 h), and 9-10 cm which corresponded to 0.6 h(0.1-2.5 h). The curve of labor duration showed a slow uptrend with time on the horizontal axis and cervical dilatation on the vertical axis. Conclusions The curve of labor duration exhibits a slow uptrend with neither an acceleration phase nor a deceleration phase. It is important to redefine the time span of labor duration in China for appropriate clinical treatment.