Endometriosis and closely related endometriotic cysts can cause infertility. In endometriosis, there is a risk of female infertility of up to 30% to 50%. The abnormal growth of endometrial tissue with each female hormonal cycle causes adhesions and scars from forming in the organs where it is. This, in the case of the female reproductive organs can be fatal for the smooth passage of the ovum to the uterus. If the egg cannot proceed through the fallopian tubes into the uterus, the fertilization and implantation can’t take place, so the egg wont develop disallowing the conception.
The mechanisms by which endometriosis may cause infertility is not clearly understood, particularly when the extent of endometriosis is low.
Still possible mechanisms include: