Endometriosis is a condition where the endometrium, which normally lines the uterus and has growth potential, is found outside of the uterine cavity, commonly in the ovaries. The typical clinical manifestation of endometriosis is abdominal pain during menstruation. Such pain intensifies as the condition progresses and can ultimately impact the patient's work and daily life, to the extent that they may not be able to work normally. Thus, endometriosis can become quite severe over time and may lead to infertility in women who wish to conceive.