The first reason is that the endometrium sheds during menstruation and produces prostaglandins, which can cause uncoordinated contractions of the uterus and lead to menstrual pain. Secondly, if there is pelvic inflammatory disease, it will aggravate the pelvic congestion during menstruation, which will also lead to stomach pain. Thirdly, abnormal development of the uterus, such as malformation of the uterus, can lead to uncoordinated contractions of the uterus during menstruation, which can also cause the possibility of dysmenorrhea. It is recommended that if you have pain in the lower abdomen during your period, it is best to have a checkup after your period clears to understand the cause of the dysmenorrhea, and then give the appropriate treatment according to the cause, so that you can achieve a complete cure for dysmenorrhea.