Contractions are short for uterine contraction force. They occur with a sensation of tightening and hardening of the belly, and the pain is felt throughout the abdomen, usually below the navel, and can gradually spread to the lower abdomen. The contractions are rhythmic, symmetrical, polar and retractive. When contractions start to intensify, similar to menstrual cramps, when they become regular contractions, the interval is shortened and the pain will gradually spread to the lower abdomen, with a sensation of back pain or defecation, and the whole abdomen will become hard and bulging. However, some pregnant women may feel only mild abdominal pain during contractions. If there are regular contractions, each contraction lasts 30-40 seconds with an interval of 5-6 minutes, accompanied by the disappearance of the cervical canal and dilatation of the uterus, it indicates that the pregnant woman is about to start labor. Pay attention to provide a comfortable environment for the pregnant woman, reduce anxiety, distract her and relieve the pain. The painful sensation of contractions varies from person to person, so it is important to cooperate with the doctor to use practiced breathing exercises to relieve contraction pain and help deliver the baby smoothly.