REVIEW ARTICLE Neuraxial anesthesia in obstetric patients receiving anticoagulant and antithrombotic drugs A.J. Butwick, B. Carvalho Department of Anesthesiology, Stanford University School of Medicine, Stanford, California, USA Introduction Spinal hematoma and neuraxial anesthesia Guidelines for neuraxial techniques and anticoagulation Individual drugs Heparin Low-molecular-weight heparins Warfarin Aspirin Fondaparinux Thienopyridines (clopidogrel, ticlopidine) Glycoprotein IIb/IIIa inhibitors Direct thrombin inhibitors References Introduction Anticoagulation is indicated for a variety of obstetric and medical conditions in women of childbearing age. Recent guidelines from national and international orga- nizations, the Pregnancy and Thrombosis Working Group and the American College of Chest Physicians, have highlighted the importance of anticoagulant ther- apy in the prophylaxis and treatment of venous throm- boembolism in pregnancy, and in pregnant patients with mechanical heart valves. 1,2 Thromboprophylaxis may also be prescribed for the prevention of adverse preg- nancy outcomes such as recurrent early pregnancy loss and placental abruption, and in patients with inherited or acquired thrombophilias. Spinal hematoma and neuraxial anesthesia Epidural spinal hematomas are the most common type of spinal hematoma, followed by subarachnoid hemato- mas (75% and 16% of published cases reported between 1826 and 1996 respectively), with many cases having unknown etiology. 3 Anticoagulant and antithrombotic drugs can increase the risk of spinal hematoma forma- tion, especially following neuraxial blockade. 4 In partic- ular, the introduction of low-molecular-weight heparin (LMWH) in the United States in 1993 was associated with an increased incidence of patients with spinal hematoma following neuraxial anesthesia (nearly 60 cases were reported over a 5-year period). 5 Neuraxial anesthetic practice guidelines have been developed and revised to minimize the risk of spinal hematoma in patients receiving LMWH as well as other newer anticoagulants. 6,7 The use of anticoagulant and antithrombotic drugs in pregnant patients poses significant challenges to obstet- ric anesthesiologists as neuraxial techniques are com- monly used to provide labor analgesia and anesthesia for cesarean delivery. The incidence of spinal hematoma after neuraxial blockade in obstetric patients receiving anticoagulation remains unknown. A retrospective study by Moen et al. of neuraxial anesthetics, which included 50 000 spinal and 205 000 epidural blocks in obstetrics, reported one spinal hematoma following obstetric epidu- ral catheter removal and one following spinal blockade, both in patients with HELLP syndrome. 8 Other studies (meta-analysis/national audit) of complications follow- ing epidural blocks in obstetric patients reported an inci- dence between 0 and 0.5:100 000. 9,10 Accepted June 2009 Correspondence to: Dr. Alexander Butwick, Department of Anesthe- siology (MC:5640), Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305 USA. Fax: 650-725-8544. E-mail address: ajbut@stanford.edu International Journal of Obstetric Anesthesia (2010) 19, 193–201 0959-289X/$ - see front matter  c 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijoa.2009.06.008 www.obstetanesthesia.com