It usually takes about 5 hours for menstruating mothers and 10-11 hours for primiparous mothers, but the exact time varies from person to person and generally should not exceed 24 hours. The opening of the uterus to two fingers indicates that the labor has entered into the process of labor. Under normal circumstances, the contraction of the uterus at the beginning of labor will be accompanied by the receding of the cervical canal and the descent of the fetal head, and the intensity of contraction will be from weak to strong, and so on repeatedly contracting and relieving until the end of labor. The cervix is tighter in primiparous women than in menstrual women, so it takes longer for the uterus to open fully than in menstrual women. However, the duration of labor may vary depending on the intensity of contractions and the condition of the birth canal. It is recommended that pregnant women always pay attention to the regularity, intensity and interval of their contractions while waiting for delivery, stimulate contractions by massaging the nipples, eat easily digestible food and keep sufficient energy.