The antiphospholipid syndrome (APS) is characterized by the presence of specific autoantibodies in association with certain clinical conditions, most notably arterial and venous thrombosis and adverse pregnancy outcomes. Clinically, the diagnosis can be suspected after any of the following outcomes: an episode of thrombosis, three or more unexplained consecutive spontaneous abortions prior to 10 weeks’ gestation, one or more unexplained deaths of a morphologically normal fetus after 10 weeks’ gestation, or a preterm delivery at less than 34 weeks due to preeclampsia or placental insufficiency. In addition to these clinical features, laboratory criteria include the identification of at least one of the following three antiphospholipid antibodies: (1) anticardiolipin antibodies, (2) anti-beta-2-glycoprotein I antibodies, or (3) the lupus anticoagulant (see Chapter 20).
The optimal treatment for APS in pregnancy is unclear but generally involves administration of a heparin compound (unfractionated or LMWH) in prophylactic amounts (5000–10,000 units subcutaneously twice per day for the former) and low-dose aspirin (81 mg). Although anticoagulation is particularly prudent in women with a history of thrombosis, there is also evidence that this management reduces the risk for spontaneous abortion in women with recurrent pregnancy loss from APS. It is not clear whether continuation of therapy beyond the first trimester decreases the risk for stillbirth or placental dysfunction; however, treatment is typically continued through pregnancy and the early postpartum period for thromboprophylaxis. LMWH is also commonly used for this indication (30–40 mg subcutaneously once per day); however, it is not clear that LMWH has the same effect on reducing the risk of recurrent abortion as unfractionated heparin. Either prophylactic or therapeutic dosing strategies may be appropriate depending on the patient’s history and clinical risk factors. The use of corticosteroids and intravenous immunoglobulin is of unclear benefit in these patients, and neither treatment is recommended.
American College of Obstetricians and Gynecologists. No. 132: Antiphospholipid syndrome. Obstet Gynecol. 2012 Dec;120(6):1514–21. [Reaffirmed 2019]
et al. Antiphospholipid syndrome and recurrent miscarriage: a systematic review and meta-analysis. J Reprod Immunol. 2017 Sep;123:78–87.