Current status of immunologic recurrent pregnancy loss.

Normal mammalian pregnancy is confronted with a great number of self (autoimmune) and foreign (alloimmune) antigens that modulate the immune system of the mother. When maternal immune response is affected, recurrent pregnancy loss can result. Recurrent pregnancy loss affects 2% to 5% of reproducing couples. Half of these failures can be explained by genetic, hormonal, infectious, and anatomic factors. Eighty percent of the unexplained failures are proposed to have an immunologic cause. HLA typing, mixed lymphocytotoxic antibody tests, mixed lymphocyte culture reactions, lupus anticoagulant tests, and antiphospholipid antibody determination are methods used to study and differentiate between auto- and alloimmune response. Experimental therapies, including leukocyte immunization, seminal plasma suppositories, intravenous immunoglobulin, aspirin and prednisone, and heparin, have been tried to manage this condition. Results of randomized placebo-controlled clinical trials will aid in the choice of treatment for recurrent pregnancy loss. New assays to diagnose auto- and alloimmune factors in recurrent pregnancy loss are being investigated.