Factors affecting labor duration in Chinese pregnant women

The aim of the study was to explore the role of parity, maternal age, medical interventions, and birth weight with respect to labor duration and cervical dilation. A total of 1601 pregnant women who had a singleton term gestation, spontaneous onset of labor, vertex presentation, vaginal delivery, and a normal perinatal outcome were reviewed. The retrospective study was conducted in patients from West China Second University Hospital of Sichuan University during June 2008 to June 2013. There were 1367 nulliparous women and 234 multiparous women analyzed. The first stage (8.3 ± 3.8 vs 5.0 ± 2.6 hours), latent phase (5.1 ± 3.2 vs 3.5 ± 2.4 hours), active phase (3.2 ± 1.8 vs 1.5 ± 1.0 hours), second stage (44 ± 31 vs 18 ± 14 minutes), and total stage of labor (9.1 ± 3.9 vs 5.4 ± 2.6 hours) were all longer in nulliparous than in multipara women (all P < .05); but no significant difference in the third stage of labor (both 7 ± 4 minutes). In nulliparous women, the average time of first stage of labor increased by 58.257, 171.443, and 56.581 minutes due to artificial rupture of membranes, labor analgesia, and birth weight increased by 1 kg, respectively, but it decreased to 63.592 minutes by oxytocin usage, and the difference was significant. The average time of first stage of labor in nulliparous women aged from 26 to 30 years increased by 2.356 minutes compared to one in 20 to 26 years, but it increased by 1.802 minutes to the one in 30 to 39 years, compared to 20 to 26 years and the difference was not significant. The results were basically similar after multipara women were included. Labor was significantly shorter in multiparous women than that in nulliparous women. Increased birth weight significantly increased in the length of the active phase and the second stage among nulliparous women. The increase of age, artificial rupture of membranes, labor analgesia, and the increase of birth weight tends to increase the time of first stage of labor and total labor duration, whereas oxytocin could shorten it.