The abdominal distension before menstruation may be related to endocrine changes, cold, cold, blood viscosity changes, as follows: 1, endocrine changes: endocrine, estrogen and other levels change dramatically before menstruation, fluctuations are relatively large, triggering pelvic, abdominal congestion, bruising, thus causing damage to the function of the pelvic organs, triggering abdominal distension; 2, cold, cold: women before menstruation, abdomen, waist, hips Even the lower extremities are cold, cold, will also cause abdominal distension; 3, blood viscosity changes: before menstruation is in the pre-bleeding, blood viscosity changes are relatively large, which can trigger the abdominal organs of people with sensitive constitutions to be damaged, such as possible chronic pelvic inflammatory disease, chronic adnexitis and other gynecological inflammatory diseases, because of changes in blood flow, resulting in changes in blood viscosity, physical decline, causing sudden onset, resulting in abdominal distension.