There are several causes of uterine tightness, full-term pregnant women may be prenatal contractions, early pregnancy may be a precursor to miscarriage, prostate secretion during menstruation, non-pregnant uterine inflammation and so on. 1. full-term pregnant women may be prenatal contractions: more than thirty-seven weeks of pregnancy, if there is a burst of uterine tightness, produced by the regularity of this situation need to go to the hospital in a timely manner to do prenatal checkups, hospitalization and wait for the birth of a child. 2. Early pregnancy may be a precursor to miscarriage: early pregnancy if there is a burst of uterine tightness, or accompanied by pain, or vaginal bleeding symptoms, etc., may be a precursor to miscarriage or symptoms after fetal arrest. 3. Excessive secretion of the prostate gland during menstruation: A burst of uterine tightness during menstruation is a sign of dysmenorrhea caused by an exuberant secretion of the prostate gland in the body. 4. Non-pregnancy uterine inflammation: Non-pregnancy, non-menstrual period of uterine tightness and pain for a while, may be due to uterine myositis, endometritis, uterine adenomyoma, adnexitis, pelvic inflammatory disease, uterine cancer, cervical cancer and other causes. Patients with tightness in the uterus need to go to the hospital in time, and the doctor will formulate an individualized diagnosis and treatment plan according to the specific condition, so as to avoid delaying the condition.