Anticoagulation for pregnant women with mechanical heart valves: a systematic review and meta-analysis

  • Rohan D’Souza, Jackie Ostro, Prakesh S. Shah, Candice K. Silversides, Ann Malinowski, Kellie E. Murphy, Mathew Sermer, Nadine Shehata
  • European Heart Journal, March 2017, Oxford University Press (OUP)
  • DOI: 10.1093/eurheartj/ehx032

Blood thinners for pregnant women with mechanical heart valves

What is it about?

Pregnant women with mechanical heart valves are at a very high risk of developing blood clots that could lead to serious harm including death. They are therefore advised to use blood thinners throughout pregnancy. However, some of these blood thinners cross the placenta and can result in malformations, serious bleeding and death of the fetus. Choosing the optimal blood thinner for these women is therefore extremely challenging. This systematic review summarizes all the available literature on the topic to help pregnant women and their physicians come to shared decisions based on the most up-to-date evidence.

Why is it important?

This paper reviews all data from 1969 to summarize risks to mother and fetus/neonate. It shows that although medications such as warfarin are associated with the lowest risks to the mother, the fetal risks are extremely high. Similarly, low-molecular weight heparin that is not recommended for these women, is associated with extremely low fetal risks, although the risks to the mother are higher than with warfarin.


rohan d'souza
Mount Sinai Hospital, University of Toronto, Toronto, Canada

The findings of this study suggest that the choice of blood thinners in pregnant women with mechanical heart valves remains complex and must involve shared decision making, taking patient values and preferences into account. There may be a role for low molecular weight heparin in these women. The safety of unfractionated heparin is questionable.

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