This report presents preliminary data for 1999 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of the mother. Data on marital status, prenatal care, cesarean delivery, and low birthweight rate are also presented. Data are based on a more than 97% sample of births for 1999. The crude birth rate in 1999 was 14.5% per 1,000 population, a slight decline from 1998 (14.6), returning to the level of 1997. However, the fertility rate, limited to women aged 15 to 44 years, was 65.8 in 1999, a slight increase over the rate for 1998. The birth rate for teenagers continued to decline for 1998-1999, dropping 3% to 49.6 births for 1,000 females aged 15 to 19 years. The 1999 rate for teenagers is 20% lower than the recent high point in 1991. Birth rates for 15-19 year-old Hispanics remained substantially higher than that of other groups. While birth rates for women aged 20 to 24 years declined slightly between 1998 and 1999, both rates for women in their 30s and 40s continued their long increase. Overall, the number of births to unmarried women was up about 1% due to the continued increase in the number of unmarried women of childbearing age. (Contains 9 tables and 12 references.) (Author/SLD)