Labor patterns in Asian American women with vaginal birth and normal perinatal outcomes

The pattern of normal labor progression can help to define prolonged labor and dystocia. Several studies had tried to establish the process of normal labor in different races. Previous findings in Asian women were limited and often incomparable. Our aim was to examine labor patterns in Asian American women.

A total of 3079 women with singleton term gestation, vertex presentation, vaginal delivery, and a normal perinatal outcome were extracted from the Consortium on Safe Labor study. A repeated measure analysis and an interval-censored regression were applied to depict the average labor curves and estimate the time interval of cervical dilation by 1 cm, respectively. A sensitivity analysis was conducted to assess the impact of oxytocin augmentation. The cumulative duration of the 1st stage of labor was calculated to draw a partograph.

It took an average of 5.2 hours for nulliparous Asian women with spontaneous labor onset to complete the 1st stage of labor, and the 95th centile was 14.4 hours. Labor progressed at a similar rate between nulliparous and multiparous women before 6 cm. Afterward, multiparous women progressed noticeably faster than nulliparous women. The differences in labor duration between women with and without oxytocin augmentation were <0.5 hour for both nulliparous and multiparous women.

A new partograph that restricted the diagnosis of dystocia to the slowest 5% of nulliparous women with normal perinatal outcomes was proposed. The labor pattern in Asian American women was similar to that of the overall United States population.