Analysis of Premature Mortality Rates

Abstract

During the years of 1941 to 1946, 2,910 premature infants were admitted to the Premature Station of the Children's Division of Cook County Hospital. Of this number 17.9% died. The influence of birth weight on survival rate was demonstrated. There were more female premature infants than males (1.23:1). The female infants had a higher survival rate than the male infants (15.3% mortality rate for females as compared with 21.9% for males). There were more nonwhite than white premature infants in this series. The nonwhite infants had a mortality rate of 15.7% whereas the white infants had a mortality rate of 20.6%. Possible explanations for this difference included racial factor and the factor of transportation of a prematurely born infant from one place to another. Of the infants born at Cook County Hospital where the factor of transfer was nonexistent, nonwhite infants had a mortality rate of 16.3%; the white infants, 21.1%. Female infants survived better than did the male infants (female mortality rate, 13.4%; male mortality rate, 22.2%). Of the infants transferred to Cook County Hospital, the white infants survived better than the nonwhite (21% as compared with 25.3%). The female infants in this group likewise showed greater survival ability as compared with the male infants (20.2% for females; 24.1% for males). There was no month of the year in which prematurity was consistently higher than the other months. The death of prematurely born infants likewise is not influenced by the month of the year. The mortality rate is related to the number of admissions and not to month or season.