The study is a prospective, monocentric, randomized controlled, two-armed, pilot-study conducted at Department for Women's Health, Tuebingen, Germany.

In this Post Market Study it will be determined whether and to what extent the two surgical procedures for ovarian endometrioma treatment (standard cystectomy versus APC) may affect the ovarian reserve by comparing changes in serum AMH levels after treatment.

Seventy-two (72) patients who meet all eligibility criteria will undergo surgical procedure. The patients will be randomized into the group with standard cystectomy treatment or with APC treatment. Per group n=36 patients will be treated i.e., 1:1 randomization.

A pre-specified primary endpoint analysis is planned after the last patient has undergo Visit 4 (Follow-up after 6 months) to analyze the primary endpoint.

Screening takes place during the first visit (V1). During the second visit (V2) the participants will receive the ovarian endometriosis treatment procedure either with the APC or the standard cystectomy. Standard procedure (standard cystectomy) will be performed for additional endometriosis lesions. The follow up visits (V3 - V5) will take place after three, six and twelve months. Visit 3 and Visit 4 will take place at the study site and AMH will be measured. Whereas Visit 5 will take place via telemedical contact, i.e. phone call.

Inclusion Criteria:

• Indication for surgical endometrioma treatment according to patient symptoms
• Signed informed consent

Exclusion Criteria:

• Expected lack of patient compliance or inability of the patient to understand the purpose of the clinical trial
• Prior procedures at the ovaries
• Recurrent endometrioma (patients with recurrent endometriosis outside of the ovar, e.g. peritoneal endometriosis lesions can be included)
• Pregnant or breastfeeding patients
• Participation in any other clinical study that could affect the AMH level or pregnancy