This report presents 1998 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics, including: (1) age, live-birth order, race, Hispanic origin, marital status, and educational attainment; (2) maternal lifestyle and health characteristics, such as medical risk factors, weight gain, and tobacco and alcohol use; (3) medical care utilization by pregnant women, including prenatal care, obstetric procedures, complications of labor and delivery, attendant at birth, and method of delivery; and (4) infant health characteristics, including period of gestation, birthweight, Apgar score, abnormal conditions, congenital abnormalities, and multiple births. Also presented are birth and fertility rates by age, live-birth order, Hispanic origin, and marital status. Selected data by mother's state of residence are shown including teenage birth rates and total fertility rates, as well as data on date of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Birth and fertility rates increased in 1998 by about 1%, the first increase since 1990. (Contains 60 tables, 9 figures, and 78 references.) (Author/SLD)