**1. Introduction**

Endometriosis is characterized by the presence of endometrial-like functional tissue located outside the uterine cavity, most commonly in the pelvic peritoneum, ovaries and rectovaginal septum, and more rarely in the pericardium, pleura and central nervous system. The studies indicate a prevalence of up to 20% of women of reproductive age [1] and 30–50% of infertile women with endometriosis [1].
