Low-molecular-weight heparin in pregnant women with prosthetic heart valves

Background and aim of the study: Low-molecular-weight heparin (LMWH) is considered a recommended anticoagulation option in pregnant women with prosthetic heart valves. However, few data are available regarding the efficacy and safety of LMWH in this setting. Methods: In 1999, the authors' institution developed a standardized anticoagulation protocol for pregnant women with prosthetic heart valves, which included LMWH administered between six and 12 weeks' gestation, and after 36 weeks, with prespecified target levels, and additional low-dose aspirin. Herein is presented the initial experience using this anticoagulation regimen. Results: Among five women with prosthetic heart valves treated with LMWH during part of their pregnancy, four had uneventful pregnancies while one suffered a coronary artery embolus. A review is provided of the current state of knowledge regarding anticoagulation in pregnancy, with emphasis placed on the importance of strict monitoring of anticoagulation levels. Conclusion: Given the drawbacks of other forms of anticoagulation, and within the constraints of available data, LMWH appears - when administered with caution - to be an acceptable alternative in pregnant women with prosthetic heart valves.