An assessment of the incidence of maternal mortality in the United States.

Recent studies in several states have found that the incidence of maternal mortality is higher than traditional vital statistics reports indicate. Since no comprehensive national study has been done to evaluate the completeness of maternal mortality ascertainment through the national vital statistics reporting system, the Centers for Disease Control (CDC) undertook such a study with the assistance of the National Center for Health Statistics and state health departments. The state health departments provided CDC with death certificates for all pregnancy-related deaths occurring during 1974-78. We reviewed and classified these certificates using both International Classification of Diseases, Adapted, Eighth Revision (ICDA-8) and International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) maternal death codes. We found that the actual incidence of maternal mortality for 1974-78 was approximately 20 per cent and 30 per cent greater than that published in national vital statistics reports using ICDA-8 and ICD-9-CM, respectively.