Sound information is the prerequisite for health action: without data on the dimensions, impact and significance of a health problem it is neither possible to create an advocacy case nor to establish strong programmes for addressing it. The absence of good information on the extent of the burden of maternal ill-health resulted in its relative neglect by the international health community for many years. Maternal deaths are too often solitary and hidden events that go uncounted. The difficulty arises not because of lack of clarity regarding the definition of a maternal death, but because of the weakness of health information systems and consequent absence of the systematic identification and recording of maternal deaths. In recent years, innovative approaches to measuring maternal mortality have been developed, resulting in a stronger information base. WHO, UNICEF and UNFPA estimates for the year 2000 indicate that most of the total 529,000 maternal deaths globally occur in just 13 countries. By contrast, information on the global burden of non-fatal health outcomes associated with pregnancy and childbearing remains patchy and incomplete. Nonetheless, initial estimates based on systematic reviews of available information and confined to the five major direct pregnancy-related complications indicate a problem of considerable magnitude.