Test for Thrombophilia in Cases of Late Fetal Loss.

BEAVER CREEK, COLO. -- Only a small percentage of obstetric situations calls for testing a patient for a heritable thrombophilia, Dr. Robert M. Silver said at a perinatal conference sponsored by the University of California, Irvine.

One of those situations is unexplained fetal death in the second or third trimester, said Dr. Silver of the University of Utah, Salt Lake City, an expert in thrombophilias and pregnancy.

Other obstetric patients who probably merit testing are those with a family history of thrombosis, those with unexplained thrombosis, and those with severe preeclampsia with onset before 34 weeks' gestation.

Although heritable thrombophilias have been associated with many obstetric complications (see related story), most experts do not recommend testing in cases of recurrent spontaneous abortion, mild preeclampsia, placental abruption, or intrauterine growth restriction. The association in these cases either is not based on strong enough data or is not thought to occur with enough frequency to justify the cost, which can run into hundreds of dollars if a full array of tests is run.

Some have recommended routine screening for common heritable thrombophiias in pregnancy But "I don't think we have enough information to make that useful," Dr. Silver said.

When testing is called for, he recommended testing for factor V Leiden mutation and the prothrombin mutation and performing immunoassays for anticardiolipin antibodies (for antiphospholipid syndrome) and lupus anticoagulant.

Testing for other thrombophilias is not recommended because the conditions are too rare, the results of the tests are too variable, or the information on what to do with the results is too unclear.