[Anticoagulation in pregnancy and post partum in heat valve diseases, thrombosis or atrial fibrillation: fetal risk versus maternal thromboembolism].
Patients with mechanical valve prostheses are at high risk for thromboembolic events, valve thrombosis and mortality during pregnancy. The most effective anticoagulation for the mother is achieved with oral anticoagulants which may be associated with embryopathy in the baby. The risk of embryopathy and the risk of hemorrhage during the remainder of the pregnancy depend on the intensity of anticoagulation induced in the fetus and the dose of the oral anticoagulant used. Recent studies suggest that a warfarin dose of less than 5 mg and an INR of less than 3 does not induce embryopathy and is associated with a low rate of fetal complications (15%). Heparin has been recommended as the anticoagulant of choice during pregnancy, because it does not cross the placental barrier and does not cause embryopathy. Yet all forms of unfractionated heparin application (low dose, aPTT-ratio-adjusted, during the entire pregnancy or during the first trimester) are associated with a higher rate of maternal complications and death than oral anticoagulants given throughout pregnancy until the 36th week of pregnancy. Also the total fetal outcome (abortion and stillbirth) is not improved by heparin. To avoid fetal and maternal complications, particularly hemorrhage during premature labor, mothers should be admitted to the hospital in the 36th week for conversion from oral anticoagulants to heparin, preferentially given i.v. prior to delivery. Vaginal delivery should be avoided under therapeutic oral anticoagulation and cesarean section preferred after neutralization of anticoagulation. The optimal INR-monitored intensity of anticoagulation by the patient is one promising way to reduce complications and increase efficacy and safety. Randomized studies including low molecular weight heparin and oral anticoagulants in patients with mechanical valve prostheses are needed, with careful monitoring of laboratory parameters and cardiac follow-up. This requires close cooperation between cardiologists, gynecologists and hemostaseologists.
Gohlke-Bärwolf
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C
Klinische Kardiologie I Herz-Zentrum Bad Krozingen Südring 15 79189 Bad Krozingen. Christa.Gohlke-Baerwolf@herzentrum.de
D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000097:blood / Q000188:drug therapy*; D001780:Blood Coagulation Tests; D005260:Female; D006349:Heart Valve Diseases / Q000097:blood / Q000188:drug therapy*; D006493:Heparin / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood / Q000188:drug therapy*; D011644:Puerperal Disorders / Q000097:blood / Q000188:drug therapy*; D013923:Thromboembolism / Q000097:blood / Q000188:drug therapy*
D000925:Anticoagulants; D006493:Heparin