Thrombocytopenia occurring during pregnancy is a common diagnostic and management problem and may have many causes (table 1) The most common of these, along with their manifestations, are shown in the table (table 2). Asymptomatic thrombocytopenia is observed near term in about 5 percent of normal pregnancies, and thrombocytopenia, sometimes severe, develops in about 15 percent of women with preeclampsia [1], which itself occurs in about 3 to 4 percent of pregnancies in the United States (table 3) [2]. The diagnosis and management of thrombocytopenia in pregnancy will be discussed here [3]. This discussion will focus on two issues: