To assess the diagnostic accuracy for the noninvasive detection of pelvic endometriosis of the combination of two simple parameters: modifications of serum CA 125 and VAS pain score following one dose of GnRH-analog (GnRH-a).

Between January 2010 and January 2014, women scheduled for a diagnostic laparoscopy for CPP at our Department will be enrolled in the current prospective observational study. For these patients, laparoscopy represents the last diagnostic step after medical history negative for gastrointestinal, urological, musculoskeletal and psychoneurological disorders related to pelvic pain, physical examination, ultrasonographic assessment and laboratory testing. From all patients, at enrollment, blood samples for serum CA125 determination will be taken during the early follicular phase (2nd-3rd day of the menstrual cycle) and VAS score for menstrual pain will be assessed. Electrochemiluminescence immunoassay (Immunoassay Elecsys Systems, Roche Diagnostics, Italy) for serum CA125 assay will be used (kit coefficient of variation between-run 0.0% and within-run 2.0%).

During the time passed on surgery waiting list, patients will received leuprolide acetate depot (LAD) at a dose of 3.75 mg IM at the 21st day of the menstrual cycle. One month later LAD administration, serum CA125 levels and VAS score will be assessed again, and then the surgical procedure will be performed in all these patients.

After laparoscopy and definitive histological examination, the population initially enrolled will be sub-grouped according to endometriosis diagnosis in two groups, i.e. group 1 (subjects with endometriosis) and group 2 (subjects without endometriosis).

Inclusion Criteria:

• chronic pelvic pain

Exclusion Criteria:

• age less than 18 and greater than 38
• oligo-amenorrhea
• use of hormone medications (including oral contraceptives pill, progestogens, and so on)
• conditions affecting serum CA125 levels (such as, pregnancy, ovarian endometrioma seen at ultrasonography, pelvic inflammatory diseases, neoplasm, tuberculosis, hepatitis, peritonitis, recent abdominal surgery and pelvic organic disease)

Patients with chronic pelvic pain