If menstrual pain is frequent, there are the following clinical causes: the first one is primary dysmenorrhea. Since the endometrium produces a lot of prostaglandins when it is shed, prostaglandins cause the smooth muscle of the uterus to contract, and this causes pain in the lower abdomen. The second cause is secondary dysmenorrhea. The second cause is secondary dysmenorrhea, which is common in clinical practice due to the following reasons: 1. first, malformation of the uterus, such as a longitudinal uterus, which causes uncoordinated uterine contractions when menstruating, and this can lead to lower abdominal pain. 2. second, if there is pelvic inflammation, the pelvic inflammation itself is in a congested state, and pelvic congestion can increase when menstruating, so it can lead to lower abdominal pain. 3. then there is endometriosis, which causes The pain in the lower abdomen will also occur because the lesion of endometriosis will also bleed during menstruation.