Factors Affecting Immune Problems
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 certain whether APA themselves cause implantation failure, although it’s plausible. They could be markers pointing to those women who are at increased risk of immunologic implantation failure.
Additionally, early miscarriages may be due to chromosomally abnormal embryos, whereas late miscarriages (more than 7 weeks gestation) may be due to the presence of APA.