Human immunodeficiency virus infections complicating pregnancy have become a major public health problem worldwide. Infected women may transmit the virus to offspring and longitudinal studies have reported this risk to be from 13% to 40%. Differences in reported transmission risks are likely to be related to maternal plasma viremia, maternal immunologic responses, or both. Studies of antiretroviral therapy and immune based therapy to reduce the risk of perinatal transmission are needed. In addition to these fetal concerns, management in pregnancy needs to address maternal health-care needs and health care workers' concerns regarding the risk of occupational exposure. Appropriate maternal management includes serial assessments of maternal T-lymphocyte function and consideration of prophylactic and therapeutic treatment options proven effective in nonpregnant adults.