Since the end of the 1940s, when the World Health Organization assumed responsibility for the decennial revisions of the Classification of Causes of Death, the Classification came to include diseases and definitions of use in vital statistics, resulting in the Sixth Revision of the International Classification of Diseases (ICD-6). The most recent revision of this work, the International Statistical Classification of Diseases and Related Health Problems (ICD-10), is more significantly different than any revision since ICD-6, especially in the area of maternal and child health. Among the changes introduced in ICD-10 are the inclusion of obstetrical tetanus in the chapter on infectious diseases, which will facilitate the recording of this cause of maternal death; the incorporation of new definitions, such as late maternal death; and the redefinition of the perinatal period, which ICD-10 defines as starting at 22 completed weeks of gestation and ending 7 completed days after birth. This article seeks to highlight these changes and to discuss their consequences for the presentation and interpretation of indicators used in the evaluation of maternal and child health.