The purpose of this study is to evaluate the effectiveness and safety of 2.5, 5 and 10 mg doses of mifepristone against a placebo in women with laparoscopic diagnostic of endometriosis.

The hypothesis of the study is that the 5 mg mifepristone dose is safe and effective and should be used in future studies on medical treatment of endometriosis.

This is double-blind randomized clinical trial.

Examinations undertaken Thorough gynecological examination, pelvic ultrasound examination, diagnostic laparoscopy before starting treatment in order to determine the localization, extent and degree of severity of the endometrial lesions and a score was assigned in accordance with the revised American Fertility Society (AFS) classification.19 Blood samples were taken for hematological tests and hepatic function. Endometrial biopsy was performed if endometrial thickness as calibrated by ultrasound was >8 mm or if there had been abnormal bleeding in the past 3 months. After 90 and 180 days of treatment an ultrasound examination of the pelvis was carried out and then followed by diagnostic-therapeutic laparoscopy and endometrial biopsy.

Subjects Women with laparoscopic confirmed diagnosis of endometriosis who volunteered to take part in the study. Inclusion criteria: a) age between 18 and 45, b) certain diagnosis of endometriosis of any degree corresponding to the American Fertility Society (AFS); c) patients with symptoms of endometriosis: dysmenorrhea or pelvic pain not attributable to other gynecological illness and d) acceptance of the use of barrier contraceptive methods during the study. Exclusion criteria: a) breastfeeding, b) hormonal or surgical treatment for the endometriosis less than 4 months previous to study, c) diabetes, d) severe arterial hypertension, e) hepatopathy, f) renal malfunction, g) endocrinopathy, and f) any other contraindication regarding the use of antiprogestins.

Inclusion Criteria:

• Women with laparoscopic confirmed diagnosis of endometriosis
• Age between 18 and 45
• Certain diagnosis of endometriosis of any degree corresponding to the American Fertility Society (AFS)
• Patients with symptoms of endometriosis: dysmenorrhea or pelvic pain not attributable to other gynecological illness and
• Acceptance of the use of barrier contraceptive methods during the study

Exclusion Criteria:

• Breastfeeding
• Hormonal or surgical treatment for the endometriosis less than 4 months previous to study
• Diabetes
• Severe arterial hypertension
• Hepatopathy
• Renal malfunction
• Endocrinopathy
• Any other contraindication regarding the use of antiprogestins.