The authors of this paper focus on the health care services received by pregnant women and infants, and consider the ways in which these services affect child health outcomes. They examine the impact of prenatal, obstetrical, and neonatal care on two measures of infant health: the rate of low birth weight births and the rate of infant mortality. There is strong evidence that these two outcomes respond favorably to the application of appropriate health services, particularly prenatal care and neonatal intensive care. The delivery of prenatal care in the United States needs improvement: slightly more than 76% of women received early care in 1989, and discrepancies in prompt receipt of care among different ethnic and economic groups are large and persistent. Improved distribution of prenatal care services could have a significant impact on the rate of low birth weight births and infant deaths. In addition, expanded regionalization of prenatal, obstetric, and neonatal care in a coordinated approach to the entire continuum of gestation, labor, delivery, and early development holds out the promise of continued improvement in infant health. Health care initiatives need to focus more on the needs of poor families and of mothers and infants with special problems, especially high-risk pregnancies resulting from maternal substance abuse and pregnancies complicated by HIV infection. The authors describe advances in obstetrical technology and neonatology, and conclude that efforts to identify programs and activities which offer the greatest potential for improving newborn survival with the least investment should have high priority. C hildren are developing organisms. They continually grow and differentiate from one physical and psychological state to the next. An understanding of childhood health status, therefore, begins with an understanding of the conditions out of which children emerge. Intrauterine and neonatal environments are crucial determinants of a child’s well-being. A mother’s health throughout pregnancy, the process of labor and delivery, and a child’s experiences during the first critical hours and days of life will influence health status for months and years afterward. Moreover, poor birth outcomes have been associated with impeded cognitive development, reductions in years of formal schooling completed, and lower levels of lifetime earnings and other measures of economic well-being. Recognition of these principles has led policy analysts to give increasing attention to prenatal and neonatal health care services. In this paper we focus on health care services received by pregnant women and infants, and consider the ways in which these services affect child health outcomes. For our purposes, these services include prenatal medical care received by women during the course of their pregnancies, obstetrical care received at the time of delivery, and medical care received by newborn infants during the first 28 days of life (the neonatal period). We consider trends in these services over time, differentials in the receipt of these services among various groups in the population, and the impact utilization of these services has on child health outcomes. Two population outcome measures to which we devote particular attention are rates of low birth weight (LBW) and infant mortality. A low birth weight baby is one born weighing less than 2,500 grams (about 51⁄2 pounds). The LBW rate is the number of such births per 1,000 live births in the population in a given year. The infant mortality rate is measured by the annual number of deaths among children in the first year of life per 1,000 live births. Because LBW babies have a higher risk of death than normal weight babies, these two rates are closely related. Though birth weight and infant mortality each have a genetic component, birth weight depends very much upon the length and quality of the fetal experience during pregnancy while infant mortality depends also upon the type of care, medical and otherwise, that a child receives after birth. Therefore, these two measures may tell us much about the effectiveness of prenatal and neonatal care. We begin with a discussion of prenatal care and its relationship to low birth weight and then proceed to a consideration of obstetrical and neonatal care and how they affect infant mortality. We shall also mention some promising new technologies being applied in the field of