Antiphospholipid syndrome (APS)
Pregnant women with APS and prior VTE or arterial thromboses should be managed in collaboration with a haematologist or expertise in this area. Women with VTE associated with the antiphospholipid syndrome (APS) (who will often be on longterm oral anticoagulation) should be offered thromboprophylaxis with higher dose LMWH (either 50%, 75% or full treatment dose) (see Appendix IV) antenatally and for 6 weeks postpartum or until returned to oral anticoagulant therapy after delivery. [New 2015] Women with an unprovoked VTE should be tested for the presence of antiphospholipid antibodies. Persistent antiphospholipid antibodies (lupus anticoagulant and/or anticardiolipin and/or β2-glycoprotein 1 antibodies) in women without previous VTE should be considered as a risk factor for thrombosis (see Appendix I) such that if she has other risk factors she may be considered for antenatal or postnatal thromboprophylaxis. [New 2015]
Evaluation of Recommendation
Women with antiphospholipid syndrome (APS) and previous VTE are at high risk of recurrent VTE in pregnancy. A Canadian study found that APS was associated with an adjusted odds ratio for PE of 12.9 (95% CI 4.4–38.0), and for DVT 5.1 (95% CI 1.8–14.3).16 Many women with unprovoked or recurrent VTE diagnosed with APS will be on long-term oral anticoagulant therapy. There are no randomised controlled trial data to support recommendations for particular doses of LMWH in pregnancy. Case series support high prophylactic doses,63,64 but some authors recommend either intermediate (75%) or therapeutic full anticoagulant doses of LMWH26,65 and this may be appropriate for APS with recurrent previous VTE or arterial events. APS is not diagnosed unless lupus anticoagulant and/or anticardiolipin and/or β2-glycoprotein 1 antibodies are positive on two occasions 12 weeks apart.71
16. Liu S, Rouleau J, Joseph KS, Sauve R, Liston RM, Young D, et al.; Maternal Health Study Group of the Canadian Perinatal Surveillance System. Epidemiology of pregnancy-associated venous thromboembolism: a population-based study in Canada. J Obstet Gynaecol Can 2009;31:611–20. 26. Bates SM, Greer IA, Middeldorp S, Veenstra DL, Prabulos AM,
Vandvik PO; American College of Chest Physicians. VTE, thrombophilia, antithrombotic therapy, and pregnancy:
Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141 2 Suppl:e691S–736S. 63. Stone S, Hunt BJ, Khamashta MA, Bewley SJ, Nelson-Piercy C. Primary antiphospholipid syndrome in pregnancy: an analysis of outcome in a cohort of 33 women treated with a rigorous protocol. J Thromb Haemost 2005;3:243–5. 64. Hunt BJ, Gattens M, Khamashta M, Nelson-Piercy C, Almeida A. Thromboprophylaxis with unmonitored intermediatedose low molecular weight heparin in pregnancies with a previous arterial or venous thrombotic event. Blood Coagul Fibrinolysis 2003;14:735–9.
65. Robertson B, Greaves M. Antiphospholipid syndrome: an evolving story. Blood Rev 2006;20:201–12. 71. Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost 2006;4:295–306.
Tables & Appendix