Back pain during menstruation may be caused by changes in hormone levels, catching a cold or having gynecological inflammation. 1. Changes in hormone levels: during menstruation, the secretion of estrogen may stimulate endometrial hyperplasia, causing pelvic edema, while the increase in prostaglandins, stimulating uterine contraction and pain, pull leading to lumbar pain, etc., generally a normal physiological response, you can pay more attention to rest to ease. 2. Cold: due to menstruation, resistance will decline, if they do not pay attention to warmth, easy to get cold, causing menstrual blood flow is not smooth, so the phenomenon of lumbago, lumbago. 3. Gynecological inflammation: the more common is pelvic inflammatory vaginitis, if there is inflammation stimulation effect, there will also be lower abdominal pain, low back pain phenomenon. Menstrual period back pain is obvious, it is recommended to consult a doctor in a timely manner, improve the relevant examination, under the guidance of specialists to actively deal with.