[In Process Citation]

Endometriosis and infertility are frequently associated. There is controversy in the literature about the causal correlation. There is no doubt, that progressed disease causes infertility by mechanical disturbances of the reproductive organs. Mild and moderate endometriosis however is discussed to cause functional infertility by changes of the peritoneal fluid, by endocrine and immunological dysfunction. Ovulation, ovum transport, fertilisation and implantation has been shown to be negatively influenced in patients with endometriosis. Some randomised prospective clinical studies however have demonstrated, that pregnancy rates after medical or surgical treatment of endometriosis are not improved compared with no treatment of the disease. The morphological data of this study may explain these conflicting data of the past: inactive, not proliferative endometriosis is not a cause of infertility, but in contrast active proliferating disease reduces fertility and needs sufficient treatment.