Antiphospholipid syndrome is associated with various conditions, including arterial and venous thromboses, autoimmune thrombocytopenia, fetal loss, preeclampsia, intrauterine growth restriction, placental insufficiency, and preterm delivery. The American College of Obstetricians and Gynecologists (ACOG) has developed guidelines for the diagnosis and treatment of this condition. The guidelines were published in the November 2005 issue of Obstetrics & Gynecology.

Diagnosis of antiphospholipid syndrome is based on a combination of clinical history and laboratory testing. Initial diagnosis requires testing for lupus anticoagulant and anticardiolipin antibodies; patients should be diagnosed if lupus anticoagulant is present or if medium to high levels (i.e., greater than 20 binding units) of immunoglobulin G (IgG) or IgM anticardiolipid antibodies are present. Positive test results must be confirmed by a second test after several weeks. Testing for antiphospholipid antibodies should be limited to women with appropriate medical or obstetric histories.

The primary manifestations of antiphospholipid syndrome are pregnancy loss and venous or arterial thromboses. Thus, clinical criteria for laboratory testing are three or more consecutive spontaneous abortions before 10 weeks’ gestation; one or more unexplained fetal deaths at 10 weeks’ gestation or later; severe preeclampsia or placental insufficiency requiring birth before 34 weeks’ gestation; unexplained venous or arterial thrombosis; or small-vessel thrombosis in any tissue or organ with no significant evidence of vessel-wall inflammation.

Treatment of antiphospholipid syndrome during pregnancy reduces the risks of pregnancy loss, preeclampsia, placental insufficiency, preterm birth, and thrombosis. ACOG states that women with antiphospholipid syndrome and no history of thrombosis should receive prophylactic doses of heparin and low-dose aspirin during pregnancy and for six to eight weeks postpartum. For women with recurrent miscarriage, the combination of prophylactic heparin and low-dose aspirin may reduce pregnancy loss and is more effective than low-dose aspirin alone or prednisone. Although ACOG found few data on the effectiveness of treatments for women with severe preeclampsia or uteroplacental insufficiency, prophylactic heparin and aspirin generally are recommended. Initiation of heparin before conception is not supported by evidence.

Women with antiphospholipid syndrome and a history of thrombosis should receive full heparin anticoagulation throughout pregnancy and for six to eight weeks postpartum to minimize the risk of maternal thromboembolism. This can be achieved safely with warfarin (Coumadin) after delivery. The benefit of adding aspirin is unknown. After the postpartum period, patients should be referred to a physician with expertise in treating the syndrome for further anticoagulation therapy.

The effectiveness of corticosteroids and intravenous immune globulin for the treatment of antiphospholipid syndrome is uncertain.

Women with antiphospholipid syndrome who are pregnant should be instructed about the signs and symptoms of preeclampsia and thrombosis and should be examined frequently. Serial ultrasonic assessment should be considered because of the risk for growth restriction. Antepartum testing should be considered after 32 weeks’ gestation (or earlier if growth restriction is evident).

Long-term risks of antiphospholipid syndrome include thrombosis and stroke. Patients with antiphospholipid syndrome should be referred to a physician with expertise in treating the syndrome for long-term follow-up.

The use of estrogen-containing oral contraceptives has been shown to increase the risk for thrombosis in women with antiphospholipid syndrome and therefore should be avoided in these women.