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Warfarin or Heparin? Tough Choice for Pregnant Women with Mechanical Heart Valves

Katherine M. Bennett

The medical literature lacks sufficient information for clinicians to decide which anticoagulation regimen offers the lowest risk of maternal and fetal problems when the woman has a mechanical heart valve, researchers found.

Estimates of maternal and fetal risks linked to commonly used regimens were published in the Jan. 24 issue of Archives of Internal Medicine. Conversion from warfarin to heparin therapy at or before six weeks' gestation and continuation through week 12 decreases fetal risk for congenital anomalies and wastage but increases the maternal risk for valve thrombosis. Since the best regimen for these women is unclear, the authors recommend careful counseling and discussion of the risks associated with anticoagulation options. To view the article, go to