Importance of the first day death rate in infant mortality

Abstract
The conventional partition of infant mortality into neonatal and postneonatal deaths, with the 28th day postpartum as the dividing line, has lost much of its epidemiological rationale in countries with low infant death rates. Infant deaths are concentrated increasingly at the start of the neonatal period: one out of three infant deaths in the United States occurs during the first 24 hours. Circumstances of early neonatal deaths differ considerably from those of later neonatal deaths. Failure to monitor separately early and late neonatal mortality can compromise the recognition of distinct epidemiological patterns. Racial disparities in the US tend to be larger for first day deaths than for any other infant deaths. Total US infant mortality declined rapidly in the 1950s and 1960s but first day deaths rose at a steady pace. Surveillance of infant mortality, whether on the national or the community level, should encompass first day, first month and first year death rates.