Legal abortions and trends in fetal and infant mortality rates in the United States

Abstract

Using states as the units for analysis, we found no evidence that during the early 1970s in the United States the legalization of abortions influenced trends in infant mortality rates. If fetal deaths were reduced by legal abortions during that period then the influence was modest and brief. These conclusions differ substantially from all earlier studies of the relationship between legal abortions and pregnancy outcomes in the United States which examined trends in areas with many legal abortions while ignoring areas with relatively few legal abortions.

PIP: All states of the United States and the District of Columbia were used as the units for analysis and applied tests of statistical significance were used to assess the relationships between legal abortions and trends in fetal and infant mortality rates during the early 1970s. The Center for Disease Control provided counts of legal abortions performed by state of residence for each year, 1970-1973. The analysis strategy was to relate abortion-birth ratios (number of abortions/1000 live births) to differences in fetal and infant mortality rates (number of events per live birth), later year minus earlier year, for each combination of the years 1967 to 1973. There were only 2 statistically significant correlations, and these involved differences in infant mortality rates between 1967 and 1969 when there were negligible numbers of legal abortions. It is concluded that changes in infant mortality rates in the United States were not related to the legalization of abortion. The correlations between legal abortion-birth ratios and trends in fetal mortality rates were analyzed for later years. Among those aged 15-19, when the correlations involving each abortion-birth ratio were considered, there were 2 or 3 statistically significant weak correlations in the direction of reduced fetal mortality rates and earlier years, yet there were no correlations for the differences between 1973 fetal mortality rate and earlier years. It was concluded that if legal abortions decreased fetal mortality rates for women aged 15-19 that this decrease was modest and short-lived. A general conclusion from the findings is that the relationships between legal abortions and societal-level trends in fetal and infant mortality rates in the U.S. through 1973 were either modest and short-lived or neglible.