Statistics show that the improvement in the U.S. infant mortality rate began slowing down in 1981 and completely ended in 1985; this has been reflected in a significant increase in the percentage of infants born prematurely and with low birth weight. Increased attention is being given to the effects of maternal behavior during pregnancy, and inadequate prenatal care is associated with many poor birth and postnatal outcomes. The hypothesis of one longitudinal study of 100 pregnant Black and Caucasian lower- and middle-class women is that the use of prenatal health services is related to women's beliefs concerning their control over their pregnancy and birth outcomes. The model underlying this study predicts that pregnant women high in internality will use prenatal health services at an optimum level, adhere to recommended prenatal health behavior guidelines, and experience good pregnancy and birth outcomes. The study uses the Pregnancy Belief Scales, which explore pregnant women's degree of perceived control or internality about pregnancy and birth outcomes, and the extent to which pregnant women believe that chance or powerful others affect their pregnancy and birth outcomes. Early findings from the study suggest that pregnancy-related health beliefs are consistent and stable indicators of pregnancy and birth outcomes. (LB)