Endometriosis is a condition where the tissue that usually lines the inside of the uterus (endometrium) grows outside of the uterus. Endometriosis is a common cause of infertility, pregnancy loss, and IVF failure.
Infertility can occur when this condition affects the ovaries, the fallopian tubes, or the entire pelvis. This condition can also damage the egg or sperm, although why this happens is unknown.