The National Center for Health Statistics recently published a study of infant mortality from linked records, a comparison of neonatal mortality from two cohort studies in the United States. The study compares neonatal mortality of infants who were born alive during January to March 1950 with another cohort of infants born during all of 1960. It involves a subgrouping of neonatal mortality by color, sex, plurality, weight at birth, period of gestation, age of mother, total birth order, cause of death, and age at death.
The study indicates that the risk of neonatal death for white infants was 18.9/1,000 live births in the 1950 cohort and that this rate dropped to 16.9 in the 1960 cohort. Lower rates in the later cohort were evident for male and for female infants and for single but not for plural births. For the group of nonwhite infants, neonatal death rate by weight at