What do systematic reviews say?

ASA with LMWH vs placebo or IVIG

ASA with LMWH showed no clear difference in bleeding ‐ major (bleeding requiring transfusion) Length of compared with placebo or IVIG (moderate certainty).

• Antiplatelet and anticoagulant agents for primary prevention of thrombosis in individuals with antiphospholipid… 2018 · Cochrane Headline outcomes only
  RR 9 [0.49, 164.76]
  1 study · 180 participants
  Moderate

ASA + high‐dose LMWH vs ASA + low‐dose LMWH or UFH

• Antiplatelet and anticoagulant agents for primary prevention of thrombosis in individuals with antiphospholipid… 2018 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 120 participants
  GRADE not reported

Aspirin vs low molecular weight heparin

It is very uncertain whether aspirin (ASA) changes major bleeding compared with low molecular weight heparin (LMWH) (very low certainty).

• Antithrombotic therapy for ambulatory patients with multiple myeloma receiving immunomodulatory agents 2021 · Cochrane Headline outcomes only
  RR 6.97 [0.36, 134.11]
  2 studies · 781 participants
  Very low
• Antithrombotic therapy for ambulatory patients with multiple myeloma receiving immunomodulatory agents 2021 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found