What do systematic reviews say?

Heparin plus aspirin vs aspirin

Heparin plus aspirin showed no clear difference in pre‐eclampsia compared with aspirin (low certainty).

• Aspirin or heparin or both for improving pregnancy outcomes in women with persistent antiphospholipid antibodies and… 2020 · Cochrane Headline outcomes only
  RR 0.57 [0.1, 3.14]
  2 studies · 82 participants
  Low