Background: The mainstay of oral anticoagulant therapy, warfarin sodium, crosses the placenta during pregnancy and may cause fetal complications. Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) do not cross the placenta and have demonstrated utility in the prevention and treatment of thrombosis during pregnancy.
Objectives: The purpose of this study was to review treatment strategy, indication, and maternal and fetal outcomes in anticoagulated pregnancies at Kaiser Permanente Colorado.
Patients/methods: We identified 103 pregnancies in 93 mothers prescribed an anticoagulant during a pregnancy occurring between January 1, 1998 and March 31, 2005.
Results: The majority of patients were treated with UFH (89.3%). Indications for anticoagulation included venous thromboembolism (VTE) prophylaxis (53.4%), history of pregnancy loss (29.1%), acute VTE (16.5%), and history of cerebral vascular accident (CVA) (1.0%). There were no maternal deaths. Fetal demise occurred in 8 pregnancies (7.8%) at a median 14 weeks gestation (range 7-22 weeks). No fetal demise occurred in pregnancies treated for acute VTE or history of CVA. There were two occurrences of pulmonary embolism (1.9%) and two hemorrhagic events requiring transfusion (1.9%).
Conclusions: Maternal and fetal adverse events were infrequent in our population of anticoagulated pregnancies. UFH remains a viable option among more expensive LMWH products.