Statistical Analysis of the Perinatal Mortality in Iwate Prefecture by Uemtsu's Indicator

Abstract

Although the infant mortality rate in Iwate Prefecture was annualy reported to be the highest in the country in the period of ten years from 1955 to 1964, the perinatal mortality rate in the Prefecture was on a little lower level than the rate in all the country. From this fact, it is surmised that the factors influencing upon the perinatal mortality rate are somewhat different from the factors influencing upon the infant mortality. In order to elucidate the meaning of the perinatal mortality rate as a maternal and child health indicator, the author has performed statistical investigation. Perinatal mortality rate in each city, town, or village in Iwate Prefecture was calculated using the vital statistics of the Prefecture in 1955 and 1960, and the association between the perinatal mortality rate in 1955 and the rate in 1960, as well as the association between perinatal mortality rate or other maternal and child health indicator were studied. Perinatal mortality rate was also observed to be not always low in the areas where the health level was evaluated to be high by life expectancy or other indicator. Using the vital statistics of Japan in 1960, correlation coefficients between two of seven indicators, that is, late fetal mortality rate of 29 weeks or more, early neonatal mortality rate under one week, perinatal mortality rate, infant mortality rate, maternal mortality rate, Uematsu's Indicator (normal deviation of mortality) for female and the Indicator for male, were studied. And then, factor analysis was performed with the obtained correlation matrix. According to the result of factor analysis, seven indicators studied could he classified into next three groups; 1. Late fetal mortality rate of 29 weeks or more. 2. Perinatal mortality rate and maternal mortality rate. 3. Early neonatal mortality rate under one week, infant mortality rate, Uematsu's Indicator for female and Uematsu's Indicator for male. Taking these facts into consideration, it has been deducted, according to the author's opinion, that perinatal mortality rate is a useful indicator for evaluating maternal and child health level of the communities.