Contractions mainly produce a tightening sensation that some people find similar to period pain. Contractions usually occur before labor and delivery, and some pregnant women may also feel them in the middle and late stages of pregnancy, when the uterine muscles are very sensitive and are affected by changes in hormone levels, and then irregular contractions will occur. The muscles will contract, and the pregnant woman will subjectively feel tightness in the abdomen, or there is a significant feeling of falling, and some may even be accompanied by vaginal bleeding. Contractions can be categorized into false contractions and true contractions. False contractions are usually weak uterine muscle contractions, and the pain is relatively mild, at this time the mouth of the uterus will not be dilated, you need to pay attention to the observation; true contractions are often very obvious pain, and often accompanied by vaginal fluids and blood, mostly suggests that labor is approaching, and it is recommended to go to the hospital to wait for the delivery.