A retrospective study depicted that active phase of labor demarcated at 6 cm cervical dilatation is linked with a reduction in primary cesarean delivery rate, labor intervention, shorter labor duration, and fewer neonatal/fetal complications. The outcomes of 3980 singletons, term pregnant, spontaneously laboring women with cervical dilatation of 4 versus 6 cm at diagnosis of the active phase of labor were compared. 

Notably, 3403 (85.5%) of women had cervical dilatation of 4 cm, and 577 (14.5%) had cervical dilation of 6 cm when the active phase of labor was detected. Although there were considerably more multiparous women in the 6 cm group, the women in the 4 cm group were noticeably heavier at the time of delivery. In the 6 cm group, there were considerably fewer cesarean sections carried out due to fetal distress and suboptimal progress, and there were considerably fewer women who required oxytocin infusion and epidural analgesia.

The 6 cm group had a considerably shorter mean duration from the diagnosis of the active phase of labor to delivery, lower mean birth weights, and fewer neonates with arterial cord pH < 7.20 requiring admissions to neonatal critical care units. The likelihood of cesarean section was decreased by multiparity (adjusted odds ratio [AOR] = 0.488), oxytocin augmentation (AOR = 0.487), and the active phase of labor being identified at 6 cm (AOR = 0.337). The likelihood of neonatal critical care hospitalization raised by 27% (AOR = 1.73) after cesarean birth.