Due to the risk of fetal-growth abnormalities and stillbirth, serial sonographic assessment of fetal growth and antepartum testing in the third trimester is recommended by the American
College of Obstetricians and Gynecologists (2016a, 2017).
here are other agents used to treat pregnant women with APS, but with no prior thromboembolic event. Aspirin, in doses of 60 to 80 mg orally daily, blocks conversion of arachidonic acid to thromboxane A2 while sparing prostacyclin production. This reduces synthesis of thromboxane A2, which usually causes platelet aggregation and vasoconstriction, and simultaneously spares prostacyclin, which normally has the opposite efect. There appear to be no major side efects from low-dose aspirin other than a slight risk of small-vessel bleeding during surgical procedures. Low-dose aspirin does not reduce adverse pregnancy outcomes in anti phospholipid antibody-positive women without the complete APS syndrome (Amengual, 2015). Its use is recommended for women with SLE or APS (American College of Obstetricians and Gynecologists, 20 16b).
Unractionated heparin is given subcutaneously in dosages of 5000 to 10,000 units every 12 hours. Some prefer lowmolecular-weight heparin, such as 40 mg enoxaparin (Lovenox) once daily (Kwak-Kim, 2013). With therapeutic dosing, measurement of heparin levels may be useful because clotting tests can be altered by LAC. he rationale for heparin therapy is to prevent venous and arterial thrombotic episodes. Heparin therapy also prevents thrombosis in the microcirculation, including the decidual-trophoblastic interface (Toglia, 1996). As discussed, heparin binds to 3rglycoprotein I, which coats the syncytiotrophoblast. This prevents binding of ACAs and anti-3rglycoprotein I antibodies to their surfaces, which likely prevents cellular damage (Tsokos, 2011). Heparin also binds to antiphospholipid antibodies in vitro and likely in vivo. Aspirin plus heparin therapy is the most eicacious regimen (de
Jesus, 2014). However, heparin therapy is associated with several complications that include bleeding, thrombocytopenia,
TABLE 59-6. Pregnancy Outcomes (%) in 750 Women Treated for the Antiphospholipid Syndrome-the PREGNANTS Study
ACA = anticardiolipin antibodies; LAC = lupus anticoagulant.
aNonsevere only.
Data from Saccone, 201r7.
osteopenia, and osteoporosis. A description of various heparins and their adverse efects is found in Chapter 52 (p. 1012).
Corticosteroids generally should not be used with primary APS-that is, without an associated connective tissue disorder. For women with SLE or those being treated for APS who develop SLE, corticosteroid therapy is indicated (Carbone, 1999). In such cases ofseconday APS seen with SLE, the dose of prednisone should be maintained at the lowest efective level to prevent lares.