Hemorrhage, infection, toxemia, and cardiac disease are no longer the leading causes of maternal death. We studied factors causing their decline in incidence using data collected by the Committee on Maternal Welfare of the Massachusetts Medical Society between 1954 and 1985. The dramatic decline in incidence of these conditions in the Commonwealth during the study period appears to have been due to both legislative actions and improvements in medical practice. The legislative actions included licensing of maternity services, blood banks, and legalization of abortion. Cardiac-related mortality has declined due to a reduction in the prevalence of rheumatic heart disease. Changes in clinical practice that stand out were the aggressive control of the hypertensive component of toxemia leading to a reduced incidence of intracranial hemorrhage, the prompt recourse to blood transfusion for hemorrhage, and the use of broad spectrum antibiotics.