Opened three fingers hit the painless injection more still belongs to the latent period of the first stage of labor, at this time the primigravida not more than 20 hours, not more than 14 hours to reach the active period, the active period of dilatation speed should be ≥ 0.5cm / h, the mouth of the uterus to open into the second stage of labor, the period needs 2 ~ 3 hours. Painless injection is good for sedation, reduces the pain caused by contractions during labor, and also reduces the risk of fetal hypoxia. However, it does not affect the normal course of labor. Cervical dilatation is mostly in the latent stage when the uterus is contracting and the mouth of the uterus gradually begins to dilate, and the fetus will slowly descend. Cervical dilatation latent period of primigravida not more than 20 hours, not more than 14 hours to reach the active period, active period for the accelerated stage of the expansion of the mouth of the uterus, the mouth of the uterus can be opened to 4-5cm that entered the active period, the latest to 6cm to enter the active period until the mouth of the uterus open all 10cm, then it takes another 2 to 3 hours to be able to produce. Generally, the uterus can be delivered immediately after the mouth of the uterus opens 10cm. However, in case of fetal malposition, cephalopelvic disproportion, etc., cesarean section needs to be considered. When the pregnant woman enters the state of labor, she should keep a relaxed mind and cooperate with the doctor to carry out relevant examinations to ensure a smooth delivery.