Data provided in this collection were gathered to evaluate the effectiveness of a five-year program demonstrating regionalization of perinatal health care for mothers and infants. There are three distinct types of data in the collection. The first consists of records of live births in eight program regions and eight comparison regions. Included in these records are data on the size and type of institution of birth, birthweight, number of previous births and pregnancies, gestational age, and method of delivery. Also provided are demographic data such as age, race, educational level, and marital status of the mother. The unit of analysis is the live birth. The second type of data in the collection consists of matched birth and death data for infants, using the same geographical coverage as the live birth data. Each record contains the data provided in the live birth data, plus information such as the place of death, age at death, and cause of death. The unit of analysis is infant deaths for which birth data are available. The third type of data are derived from a survey of infant health at one year of age. Included in this are data on employment, education, and previous pregnancies of the mother, plus information on pre- and post-natal hospitalization, medical care, and infant health. Additional data are provided for a test, administered to each infant, of adaptive, gross and fine motor, and receptive language development.