Menstrual back pain is commonly caused by the following reasons: 1, pelvic stasis syndrome is one of the most common causes of menstrual back pain symptoms. On the one hand, it is related to physical factors, and on the other hand, it is related to long-term constipation or prolonged standing and sitting during menstruation. 2. Chronic pelvic inflammatory disease. The woman suffering from chronic pelvic inflammation, during the menstrual period pelvic tissue congestion increased, will make the original lower abdomen and lumbar pain and discomfort symptoms more obvious. 3, posterior uterus. The woman with a posterior uterus is not a disease, but the menstrual blood in the uterine cavity is not very smoothly discharged during menstruation, and the blood in the uterine cavity can easily stimulate the posterior pelvic wall and lead to lumbar pain. 4. overexertion. During the menstrual period, women engage in too strenuous sports or heavy physical labor, which can aggravate the pelvic congestion symptoms and induce or aggravate the performance of lumbago.