Best treatment for the pregnant patient with elevated Antiphospholipid Antibodies
What is the best treatment for the pregnant patient with elevated aPL abs who has had previous fetal loss but no previous history of thrombosis? How about if they have a previous history of thrombosis?
ASA (81–100 mg) daily is prescribed before conception. Once conception has occurred, heparin 7500 to 10,000 units SC twice a day or LMWH (e.g., enoxaparin 40 mg SC daily, dalteparin 5000 units SC daily) is added and continued until at least 34 weeks of gestation. The platelet count should be monitored every 2 to 4 weeks to monitor for HIT. With this combination, the rate of fetal loss is decreased by 54%, and overall 70% of these women with obstetrical APS will have successful live pregnancies. Heparin and LMWH at higher antithrombotic doses do not work any better than prophylactic doses. It is postulated that heparin and LMWH at these low doses have the ability to inhibit complement and this is the major reason they can prevent fetal demise (see Question 30). Heparin or LMWH is stopped before delivery and then reinstituted and continued at prophylactic doses for at least 1 week post delivery. Heparin is safe during breast feeding. Patients at high risk (triple positive aPL, cesarean section, age >35 years, obesity, severe preeclampsia, twin pregnancy) should continue prophylaxis for 6 weeks postpartum. Coumadin is contraindicated during pregnancy owing to fetal malformations. All patients with aPL abs should have the placenta examined by the obstetrician for evidence of infarction even if no problems occurred during pregnancy.
APS patients with a previous history of venous or arterial clot who are on chronic coumadin and become pregnant should be switched to full therapeutic doses of LMWH and low-dose ASA throughout pregnancy. In the postpartum period they can be switched back to warfarin, which is safe during breast feeding.
