Obstetric patients are a small but important group of patients in the intensive care unit (ICU). Their problems are unique and need specialized attention. Decision making may be confounded by physiologic changes in pregnancy. In developed countries with good antenatal care, comparatively fewer obstetric patients are admitted to ICUs, but the maternal mortality rate remains high in the developing countries. Medical disorders and organ dysfunction caused by critical illness of pregnancy differ from region to region. With improvement in antenatal care, the number of ICU admissions for obstetric disorders would decline in developing countries; however, this number may increase gradually in developed countries because of increasing maternal age and pregnancies in women with complicated chronic medical disorders.