Anticoagulants to prevent placenta-mediated pregnancy complications: a review of current evidence

Abstract

Placenta-mediated pregnancy complications are relatively common and are associated with significant morbidity and mortality. Although anticoagulants are increasingly being used to prevent these complications, the evidence supporting their use is limited. This article will focus on reviewing the current evidence base for the use of anticoagulants to prevent placenta-mediated pregnancy complications in women with or without identifiable thrombophilia. Controversy exists whether inherited or acquired thrombophilias cause placenta-mediated complications. Small randomized studies with methodological limitations suggest that antepartum anticoagulant prophylaxis will reduce pregnancy loss in women with both acquired and inherited thrombophilia and prior pregnancy loss. There are no published randomized controlled trials examining anticoagulant prophylaxis in thrombophilic women with prior preeclampsia, intrauterine growth restriction or placental abruption. More recently, the benefit of antepartum anticoagulant prophylaxis in women without thrombophilia with prior placenta-mediated pregnancy complications has been suggested in a small pilot randomized trial. Overall, although antepartum anticoagulant prophylaxis has the potential to reduce placenta-mediated pregnancy complications in women with and without identifiable thrombophilia, the data generated by these trials are methodologically limited and inadequate. Hence, we conclude that further trials are required prior to adopting the use of antepartum anticoagulant prophylaxis to prevent placenta-mediated pregnancy complications in routine clinical practice.