Why did postperinatal mortality rates fall in the 1970s?

Postperinatal mortality rates have shown two phases of decline since 1947 which are traditionally ascribed to social and medical improvements. These factors cannot, however, explain the arrest of decline during the 1960s. There appears to be a biological effect on child mortality rates, manifesting as a generation effect. This is due partly to continuing changes in the structure of the child population, itself a consequence of social and biological changes among the parent generation when they were children. In this study national and selected urban postperinatal deaths have been divided into two categories: "probably inevitable" and "possibly preventable". The continuing prevalence of "possibly preventable" deaths gives cause for concern. If the number of these deaths is to be further reduced, reconsideration and redeployment of community child health staff may be necessary.