Births: final data for 2001.

OBJECTIVES This report presents 2001 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco, and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS Descriptive tabulations of data reported on the birth certificates of the 4.026 million births that occurred in 2001 are presented. Denominators for population-based rates are derived from the 1990 U.S. census. As a result, rates are generally larger than would be the case if 2000-based estimates were used. The magnitude of the overestimate will vary by population subgroup; overestimates are likely greatest for those of Hispanic origin. RESULTS The number of births, the birth rate, fertility rate, and total fertility rates all declined 1 percent in 2001. The teenage birth rate reached another historic low. Birth rates for women in their twenties declined slightly, whereas rates for women aged 30 to 44 years continued to rise. Births to unmarried women changed very little. Smoking by pregnant women was down again. Women were more likely to begin care in the first trimester of pregnancy (83.4 percent). The cesarean delivery rate rose for the fifth consecutive year to 24.4 percent; the primary cesarean rate was up 5 percent and the rate of vaginal births after a previous cesarean fell 20 percent. Preterm and low birthweight levels both rose for 2001. The twin birth rate continued to climb, and following 2 years of decline, the rate of triplet/+ births also increased.