Thrombocytopenia, defined as a platelet count of <150,000/microliter occurs in 7–12% of pregnant women at delivery. While the most common cause of thrombocytopenia in pregnancy is benign and causes only a mild fall in platelet count, some etiologies are life-threatening. This review is a summary of some of the common causes of thrombocytopenia and outlines a systematic approach to diagnosis and management.