This study evaluates the optimum day of menstrual period for the excision of endometriomas to minimize the damage of surgery to normal ovarian tissue. Patients will be grouped as follicular, ovulatory and luteal according to menstrual days. Ovarian damage will be evaluated with both pathologic examination and anti-mullerian hormone levels before and after the surgery.

Endometriosis is a common gynecologic disease seen in about 10% of women in reproductive age. The most common site of endometriosis is overt. Cystic formation of ovarian endometriosis is called endometrioma (chocolate cyst). Definitive treatment of endometriomas is excision by laparoscopy. The disadvantage of this surgery is the removal of some of the normal ovarian follicles within cystectomy material. This procedure can damage the ovarian reserves with the treatment of endometriomas, which are already the cause of infertility, and lead to the conditions such as infertility or early menopause. It has been understood that the ovarian reserves of the patients who underwent endometrioma cystectomy with the decrease of the Anti-Mullerian Hormone values, which is an over reserve parameter.

Inclusion Criteria:

• 4 to 10 cm unilateral ovarian endometrioma
• having clinically indication of laparoscopic ovarian endometrioma excision

Exclusion Criteria:

• prior gynecologic surgery
• prior abdominal surgery
• additional operation in the same session
• having the diagnosis of premature ovarian failure or ovarian insufficiency
• having any diagnosis of malignancy
• having diagnosis of a non-gynecologic chronicle disease

Women who admitted to out-patient clinic between the ages of 18-40 years,had 4-10cm ovarian unilateral endometrioma and had an indication of laparoscopic ovarian endometrioma excision.

Data sharing will be decided during the study process.