A small stomach pain with bleeding may be due to dysmenorrhea that occurs during the patient’s menstrual period. For patients with dysmenorrhea, it is mainly associated with a local rise in prostaglandins in the endometrium. However, dysmenorrhea can also be caused by organic pathologies such as endometriosis, adenomyosis or chocolate cysts, which can cause pain in the belly during menstruation. If the patient is pregnant with a preterm miscarriage or ectopic pregnancy, she may also experience pain in her belly combined with bleeding and needs to go to the hospital as soon as possible to check her blood HCG level, progesterone and gynecological ultrasound to determine the next step in treatment. In addition, pelvic inflammatory disease can also be seen, and further ultrasound and gynecological examination are needed to clarify the diagnosis. If it is determined to be caused by pelvic inflammatory disease, it can be treated with oral antibiotic medication.