This chapter discusses three auto-immune hematological conditions that may complicate pregnancy: immune/idiopathic thrombocytopenic purpura (ITP), autoimmune hemolytic anemia (AIHA), and autoimmune neutropenia (AIN). They are characterized by the development of an autoantibody specific for a surface antigen on the platelet, erythrocyte, or neutrophil. ITP usually occurs in isolation but may occur with other immune cytopenias or be secondary to a systemic autoimmune condition, e.g. SLE. The pathogenesis of AIN is similar to that of other maternal immune cytopenias. Patients with symptomatic neutropenia are likely to present outside of pregnancy and have an established diagnosis. The differential diagnosis includes: drugs, viral infections, immune mediated disorders, large granular lymphocyte (LGL) disease, benign ethnic neutropenia, and CIN. For patients presenting during pregnancy, the diagnosis of AIHA requires careful exclusion of other causes of anemia, biochemical evidence of hemolysis and serological evidence that the hemolysis is immune mediated.