Complete and comprehensive surveillance of maternal mortality and maternal near miss should increase the consistency and accuracy of the data. Extremes of age, pre-existing medical conditions, language barriers, ethnicity, and socioeconomic status are recognized risk factors for maternal and obstetric complications. An important challenge to the identification of maternal near miss outcomes has historically been varying definitions between local, national, and international institutions. The majority of definitions may be classified as clinically based, organ system based, or management/intervention based. Organ-system dysfunction criteria are based on abnormalities detected by laboratory tests, such as platelet levels, and basic critical care monitoring. Complications from pre-existing medical conditions such as chronic heart disease are emerging as an important cause of maternal near miss, as improvements in medical care allow more women to live to reproductive age. Effective prevention policies are necessary to influence the long-term outcomes associated with maternal near miss.