OBJECTIVES: This report presents 2011 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal characteristics, including age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, and infant characteristics (e.g., period of gestation, birthweight, and plurality). Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. 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 3.95 million births that occurred in 2011 are presented. Denominators for population-based rates are postcensal estimates derived from the U.S. 2010 census. Birth and fertility rates for 2001-2009 are based on revised intercensal population estimates. Denominators for 2011 and 2010 rates for the specific Hispanic groups are derived from the American Community Survey; denominators for earlier years are derived from the Current Population Survey. RESULTS: The number of births declined 1% in 2011 to 3,953,590. The general fertility rate also declined 1%, to 63.2 per 1,000 women aged 15-44. The teen birth rate fell 8%, to 31.3 per 1,000 women. Birth rates declined for women in their 20s, were unchanged for women aged 30-34, and rose for women aged 35-44. The total fertility rate (estimated number of births over a woman's lifetime) declined 2% to 1,894 per 1,000 women. The number and rate of births to unmarried women declined; the percentage of births to unmarried women was essentially stable at 40.7%. The cesarean delivery rate was unchanged from 2010 at 32.8%. The preterm birth rate declined for the fifth straight year to 11.73%; the low birthweight rate declined slightly to 8.10%. The twin birth rate was not significantly changed at 33.2 per 1,000 births; the rate of triplet and higher-order multiple births also was essentially stable at 137.0 per 100,000.
OBJECTIVES: This report presents 2011 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal characteristics, including age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, and infant characteristics (e.g., period of gestation, birthweight, and plurality). Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. 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 3.95 million births that occurred in 2011 are presented. Denominators for population-based rates are postcensal estimates derived from the U.S. 2010 census. Birth and fertility rates for 2001-2009 are based on revised intercensal population estimates. Denominators for 2011 and 2010 rates for the specific Hispanic groups are derived from the American Community Survey; denominators for earlier years are derived from the Current Population Survey. RESULTS: The number of births declined 1% in 2011 to 3,953,590. The general fertility rate also declined 1%, to 63.2 per 1,000 women aged 15-44. The teen birth rate fell 8%, to 31.3 per 1,000 women. Birth rates declined for women in their 20s, were unchanged for women aged 30-34, and rose for women aged 35-44. The total fertility rate (estimated number of births over a woman's lifetime) declined 2% to 1,894 per 1,000 women. The number and rate of births to unmarried women declined; the percentage of births to unmarried women was essentially stable at 40.7%. The cesarean delivery rate was unchanged from 2010 at 32.8%. The preterm birth rate declined for the fifth straight year to 11.73%; the low birthweight rate declined slightly to 8.10%. The twin birth rate was not significantly changed at 33.2 per 1,000 births; the rate of triplet and higher-order multiple births also was essentially stable at 137.0 per 100,000.
Authors: Kristin M Myers; Helen Feltovich; Edoardo Mazza; Joy Vink; Michael Bajka; Ronald J Wapner; Timothy J Hall; Michael House Journal: J Biomech Date: 2015-03-11 Impact factor: 2.712