If low back pain occurs before menstruation, it is often clinically caused by the following reasons: 1. inflammation, such as pelvic inflammation or chronic inflammation of the cervix leading to inflammation of the sacral ligament, which will cause congestion in the pelvic tissues when menstruation occurs, so it aggravates the original inflammatory state of congestion, and pain in the lumbosacral area will occur. 2. caused by endometriosis, before menstruation the endometriosis The ectopic lesion will also be congested and the ectopic lesion will show bleeding. Therefore, back pain may occur before menstruation. It is recommended that diagnosis be made through gynecological examination and ultrasound, and once the diagnosis is confirmed, clinical treatment should be given according to the diagnosed disease.