Q: What are immunologic causes and tests for recurrent miscarriage?

A: There are few studies that definitively answer these questions and clarify the role of immune system anomalies in recurrent miscarriages.
Some explanations include the lack of a protective blocking antibody, increased NK cell numbers (natural killer cells), increased NK cell activity, factors toxic to embryo growth, increased levels of factors that stimulate the immune system to an "attack response," and absent placental surface HLA-G, an important immunosuppressive factor.
The embryotoxic factor blood test (EFT or ETF) is one of the immunologic tests that can show if a woman may benefit from high-dose progesterone-immunosuppressive therapy. Testing for NK cell numbers and activity have lead investigators to consider treatment with IViG (intravenous immunoglobin) infusion or Embrel therapy.
Immunotherapy is quite expensive and should be considered experimental.