[Anticoagulation of pregnant women with a mechanical heart valve prosthesis]

Patients with a mechanical heart valve prosthesis (MHVP) are usually anticoagulated with oral anticoagulants (OAC) to prevent thromboembolic complications. Considering the paucity of published data, the management of women with MHVP of childbearing age, who wish to become pregnant, still remains difficult and complicated. OAC may cause embryopathy during the first trimester, while neurologic complications, stillbirth and fetal death may appear during the second and third trimester. While the application of unfractionated heparin (UFH) in pregnant patients with MHVP may fail to prevent thromboembolic complications even with therapeutic dosage, only little is known about the application of body weight adjusted therapeutic dosages of low molecular weight heparin (LMWH). We report on 8 female patients, 7 with MHVP, one with atrial fibrillation, who were treated with LMWH during the whole pregnancy. No malformations or major bleeding complications were observed, no valve thrombosis or thromboembolic complications occurred. Three patients developed moderate heart failure during the third trimester, which resolved after treatment. In three patients, cesarean section was necessary, while the other five patients delivered spontaneously.Therefore, anticoagulation with body weight adjusted LMWH seems to be an alternative, safe and efficient treatment for pregnant women with MHVP. Prospective, randomized studies are needed to further evaluate this new therapeutic approach. The underlying heart disease represents a serious comorbid condition that requires continuous interdisciplinary monitoring.