Essencial Thrombocytemia is a rare chronic myeloproliferative disease of unknown etiology, characterized by markedly elevated platelet production (> 600,000/ml). It is more frequent among women above 50 years of age and may be associated with hemorrhagic or thrombotic tendencies. The authors report a case of Essencial Thrombocytemia diagnosed after several consecutive spontaneous abortions. Some clinical aspects, complications, differential diagnosis and management of this condition in pregnancy are also reviewed. An individualized, multidisciplinar approach and the treatment with acetylsalicylic acid, associated with interferon-alfa if necessary, will be the best therapeutic options for these patients.