There is a strong association between endometriosis and infertility. Endometriosis is commonly seen in women having problems conceiving. Advanced forms of endometriosis, for instance, those with chocolate cysts in the ovaries, or severe scarring that damages the Fallopian tubes, can reduce the chances of conceiving. Less severe forms of endometriosis are also associated with infertility, perhaps due to inflammatory changes with the pelvic cavity that cause harm to sperm, eggs or embryos.
There is evidence that treating milder forms of endometriosis using key-hole surgery improves natural fertility. It is unclear whether surgical treatment of endometriosis before IVF improves the chances of IVF success.