Endometriosis is defined as the presence of endometrial cells outside of the uterus that can result in pain, distortion of pelvic structures and infertility. Various reports in the medical literature suggest that endometriosis is related to a deficiency in the immune system. Impaired immune response in some women may result in ineffective removal of the endometrial cells from the pelvic area that may result in endometriosis. A number of substances are involves in the pathophysiology of the disease including cytokines and natural killer cells. Although a number of theories have been proposed in the development of endometriosis, the exact pathophysiology is still to be determined.
The natural conception rate for healthy ovulating women in their early 30s (without endometriosis) is approximately 15-20% per month and 75-85% per year of actively attempting to conceive. Conversely, the conception rate for women of a comparable age who have minimal or mild pelvic endometriosis (Stage I or II disease) is about 3-5% per month and 20-30% after 2 years of trying. The reduced conception rate in women with endometriosis may be explained by either decreased egg reserve (resulting in chromosomally abnormal embryos) or one of the following additional factors:
Altered Peritoneal Environment
Women with endometriosis may have an inflammatory reaction in the pelvis that may result in the release of toxic substances and activation of specific white cells. These toxins may reduce the natural fertilization potential of the sperm as well as the egg. In vitro fertilization (IVF) treatment involves aspirating the eggs before they are released from the ovary during the process of ovulation and prevents exposure to endometriosis related toxins. It is possible that once the eggs are released into the pelvis they are exposed to various toxins and inflammatory cells and this may be the case for sperm as well.
Immunologic Implantation Failure
Some women with endometriosis have anti-phospholipid antibodies (APA) in their circulation. Also, approximately one third of women who have endometriosis (regardless of severity) show evidence of increased Natural Killer Cell activity (NKa) in the peripheral blood and potentially in their endometrial linings. In such cases there is a higher likelihood of early or later immunologic implantation failure. In the case of early immunologic implantation failure, it is possible that rejection occurs at the time that the embryo attaches to the uterine wall. These patients may have been pregnant before, but in most instances the pregnancies may have been undetected. In the case of the latter (late implantation failure), poor implantation may result in a miscarriage. It is not ce