How long does it take for the opening of the uterus to occur is mainly related to the type of contractions, and should be analyzed on a case-by-case basis, not in general. There are regular contractions and irregular contractions. Among them, regular contractions indicate labor, that is, the mouth of the uterus is about to open. The irregular contractions are difficult to determine the time of labor. The period from regular contractions to full opening of the uterus is called the first stage of labor, while the period from full opening of the uterus to delivery is called the delivery period. For first-time mothers with regular contractions, it usually takes 12-24 hours for the opening of the uterus to be complete after a bout of pain, while for women in labor, the time required is relatively short, about 8 hours, and usually no more than 16 hours for the opening of the uterus to be complete. If the contractions are not regular and are just a bout of pain, it is difficult to tell how long it will take for the uterus to open. Therefore, pregnant women are advised to increase their walking when regular uterine contractions begin and abdominal pain appears. Wait for the uterine opening to be completely open, i.e. to the level of the tenth finger, before delivering the fetus. In this case it is necessary to be hospitalized, be patient and wait for the obstetrician to keep an eye on the opening of the uterus.