Dysmenorrhea

Inclusion Criteria

- Patients aged 20 years or older at obtaining informed consent
- Patients having the normal menstrual cycle (28+/-3 days) in the latest two menses before the final enrollment
- Patients having a total dysmenorrhea score of at least 3 points in two menstrual cycles before the final enrollment

Exclusion Criteria

- Patients with ovarian chocolate cysts and symptomatic uterine fibroids (as defined in greater detail in the study protocol)
- Patients with estrogen-dependent tumors (e.g. breast cancer, cancer of the uterine body or breast fibrocystic, etc.), and patients with cervical cancer or suspected cervical cancer (e.g. class III or greater in the cervical smear or endometrial smear examination.) 
- Patients with undiagnosed abnormal vaginal bleeding
- Patients with thrombophlebitis, pulmonary embolism, cerebrovascular disease(including transient ischemic attack, etc.), or coronary artery disease(e.g. myocardial infarction and angina pectoris, etc.), or a history of those diseases
- Patients aged 35 years or older who smoke at least 15 cigarettes per day
- Patients with migraine accompanied by prodrome (e.g. scintillating scotoma or star-shaped scintillation)
- Patients with pulmonary hypertension or valvular heart disease complicated by atrial fibrillation, and patients with a history of subacute bacterial endocarditis 
- Patients who are regularly taking nutritional products that contain St. John's Wort
- Patients who underwent surgical treatment for endometriosis by laparotomy, or laparoscopy within 2 months prior to screening
- Patients who need to use analgesics regularly for therapeutic objectives other than relief from the pain of dysmenorrhea during this study (occasional use permitted)