Valvular Heart Disease in the Pregnant Patient.
Anticoagulation for the pregnant patient with valve disease is problematic: both the underlying thrombotic disorder and the pharmacologic agents available for its treatment pose significant risks to the mother and fetus. There are no randomized controlled trial data available to guide decision-making for this patient population. Clinical treatment algorithms usually are derived from patient registries or case series with the obvious limitations of retrospective review, selection bias, historical controls, and small patient numbers. Prospective trials clearly are needed, but clinical research in the pregnant patient presents a myriad of ethical and legal challenges. Warfarin and unfractionated heparin, the mainstays of anticoagulant therapy, fall quite short in any analysis of efficacy and safety. There is an increasing use of low molecular weight heparins (LMWHs) in clinical practice but without evidence-based validation. Anticoagulant management of the pregnant patient must begin with full disclosure of the hazards and limitations of all forms of available treatments, preferably prior to conception. Treatment should be predicated on an assessment of the relative risks of thrombosis and hemorrhage. Careful monitoring and dosage adjustment are required throughout gestation, labor, delivery, and the puerperium.