Both maternal and infant death rates in the United States are much higher than in many developed countries. The interrelationships between abortions and maternal and infant mortality have been analyzed on the basis of data from the 1970s and 1980s. The legalization of abortions in 1973 resulted in a marked increase in legal abortions and marked reductions in maternal and infant mortality over the course of the 1970s. However, a wide variation in abortion rates and in the number of abortion facilities indicates that such facilities were not readily available to all segments of the population in some areas. This probably accounts in part for higher maternal and infant death rates in such areas. Smoking, small weight gain, use of alcohol and drugs in pregnancy, and excessive maternal youth or age affected the outcome of pregnancy and contributed to high rates of infant death. Infant death rates were especially high among newborns of teenagers and young adult mothers; relatively high proportions of these newborns had low birthweights; a large share of the pregnancies involved were unintended; and slightly over half of the unintended pregnancies in teenagers and young women resulted in abortion. Comparisons with findings in Sweden reveal that the rates of unplanned pregnancy, abortion, and infant mortality were all much higher in the United States than in Sweden. The differences are attributed to better contraceptive services, which were made available free or very inexpensively in Sweden. Also, the frequency of low weight births was much lower in Sweden.