Contractions 15 minutes once when regular is uncertain, the time can be from a few hours to a few weeks are possible, can be divided into true contractions and false contractions. Irregular contractions are a common manifestation of preterm labor, mainly in the form of inconsistency in the frequency and duration of contractions, which often appear at night and disappear during the day, and can be suppressed by sedation, and usually do not lead to dilatation of the uterine opening. True contractions are the opposite of irregular contractions, the frequency and duration of contractions are consistent, sedation can not be suppressed, there can be cervical tube tolerance and dilatation of the uterine opening. Pregnant women who experience contractions and are unable to differentiate between true and false contractions should seek medical attention, monitor the fetal heart rate, and follow the doctor’s instructions.