Intravenous immune globulin (IVIG) is approved for use in a number of conditions that may occur in obstetrical patients, including autoimmune thrombocytopenia and immune deficiency syndromes. IVIG also is widely used in obstetrics for nonapproved indications, such as fetal-neonatal alloimmune thrombocytopenia, antiphospholipid syndrome, and recurrent miscarriage. This review critically analyzes the use of IVIG for these indications based on the best available information. The authors conclude IVIG is effective in the management of fetal-neonatal alloimmune thrombocytopenia. IVIG appears promising as a treatment for severe fetal-neonatal alloimmune hemolysis due to antierythrocyte antibodies. A prospective multicenter trial should be undertaken. IVIG is no more effective than heparin and low-dose aspirin in the treatment of pregnancies complicated by antiphospholipid syndrome but has not been adequately evaluated in refractory cases. Finally, pending convincing studies, IVIG is not effective and should not be used for the management of recurrent miscarriage.