Births: preliminary data for 2004.

OBJECTIVES: This report presents preliminary data for 2004 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, tobacco use, prenatal care, cesarean delivery, preterm births, and low birthweight (LBW) are also presented. METHODS: Data in this report are based on 99.1 percent of births for 2004. The records are weighted to independent control counts of all births received in State vital statistics offices in 2004. Comparisons are made with 2003 data. RESULTS: The crude birth rate declined 1 percent to 14.0 births per 1,000 population. The fertility rate, however, rose slightly to 66.3 births per 1,000 women aged 15-44 years. Birth rates for teenagers 15-19 years declined modestly. The rate in 2004 was 41.2 births per 1,000 females aged 15-19 years, 1 percent lower than in 2003. Rates declined 1 percent each for teenagers 15-17 and 18-19 years. The rate for 10-14 year-olds increased slightly. The birth rate for women aged 20-24 years declined 1 percent to 101.8, a record low for the Nation. The rate for women aged 25-29 years remained essentially unchanged at 115.5 per 1,000. The birth rate for women aged 30-34 years rose less than 1 percent to 95.5 per 1,000, whereas the rates for women aged 35-39 and 40-44 years increased 3 to 4 percent each. The rate for women aged 45-49 years rose to 0.6 per 1,000. Childbearing by unmarried women rose to a record high of almost 1.5 million births in 2004, a 4-percent increase from 2003. The proportion of all births to unmarried women increased to 35.7 percent. Smoking during pregnancy declined slightly in 2004, to 10.2 percent of mothers in the 40-State reporting area. There was no improvement in timely receipt of prenatal care. In 2004, 83.9 percent of mothers in the 41-State reporting area began care in the first trimester. A record high cesarean delivery rate was reported in 2004, at 29.1 percent of all births, a 6-percent increase from 2003. The primary cesarean rate rose 8 percent, whereas the rate of vaginal birth after cesarean delivery declined 13 percent. Preterm and LBW rates each increased in 2004. More than 500,000 infants were born preterm, a rate of 12.5 percent. The LBW rate increased to 8.1 percent.     

Births: preliminary data for 2005.

OBJECTIVES: This report presents preliminary data for 2005 on births in the United States. U.S. data on births are shown by age, live-birth order, race, and Hispanic origin of mother. Data on marital status, cesarean delivery, preterm births, and low birthweight (LBW) are also presented. METHODS: Data in this report are based on 99.2 percent of births for 2005. The records are weighted to independent control counts of all births received in state vital statistics offices in 2005. Comparisons are made with 2004 data. RESULTS: The crude birth rate in 2005 was 14.0 births per 1,000 total population, unchanged from 2004. The general fertility rate, however, rose to 66.7 births per 1,000 women aged 15-44 years in 2005, the highest level since 1993. The birth rate for teenagers declined by 2 percent in 2005, falling to 40.4 births per 1,000 women aged 15-19 years, the lowest ever recorded in the 65 years for which a consistent series of rates are available. The rate declined for teenagers 15-17 years to 21.4 births per 1,000, but was essentially stable for older teenagers 18-19 years. The birth rate for women aged 20-24 years rose in 2005, whereas the rate for women aged 25-29 years was essentially unchanged. The birth rates for women aged 30 years and over rose to levels not seen in almost 40 years. Childbearing by unmarried women increased to record levels for the Nation in 2005. The birth rate rose 3 percent to 47.6 births per 1,000 unmarried women aged 15-44 years; the proportion of all births to unmarried women increased to 36.8 percent. The cesarean delivery rate rose by 4 percent in 2005 to 30.2 percent of all births, another record high for the Nation. The preterm birth rate continued to rise (to 12.7 percent in 2005) as did the rate for LBW births (8.2 percent).     

Births: preliminary data for 2000.

OBJECTIVES: This report presents preliminary data for 2000 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, prenatal care, cesarean delivery, and low birthweight are also presented. METHODS: Data in this report are based on more than 96 percent of births for 2000. The records are weighted to independent control counts of births received in State vital statistics offices in 2000. Comparisons are made with 1999 final data. RESULTS: The number of births rose 3 percent between 1999 and 2000. The crude birth rate increased to 14.8 per 1,000 population in 2000, 2 percent higher than the 1999 rate. The fertility rate rose 3 percent to 67.6 per 1,000 women aged 15-44 years between 1999 and 2000. The birth rate for teenagers, which has been falling since 1991, declined 2 percent in 2000 to 48.7 births per 1,000 females aged 15-19 years, another historic low. The rate for teenagers 15-17 years fell 4 percent, and the rate for 18-19 year olds was down 1 percent. Since 1991, rates have fallen 29 percent for teenagers 15-17 years and 16 percent for teenagers 18-19 years. Birth rates for all of the older age groups increased for 1999-2000: 1 percent among women aged 20-24 years, 3 percent for women aged 25-29 years, and 5 percent for women in their thirties. Rates for women aged 40-54 years were also up for 2000. The birth rate for unmarried women increased 2 percent to 45.2 births per 1,000 unmarried women aged 15-44 years in 2000, but was still lower than the peak reached in 1994. The number of births to unmarried women was up 3 percent, the highest number ever reported in the United States. However, the number of births to unmarried teenagers declined. The proportion of women who began prenatal care in the first trimester of pregnancy (83.2 percent) did not improve for 2000, nor did the rate of low birthweight (7.6 percent). The total cesarean rate rose for the fourth consecutive year to 22.9 percent, the result of both a rise in the rate of primary cesarean deliveries and a decline in the rate of vaginal births after previous cesarean delivery.     

Births: preliminary data for 2001.

OBJECTIVES: This report presents preliminary data for 2001 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, prenatal care, cesarean delivery, and low birthweight are also presented. METHODS: Data in this report are based on more than 96 percent of births for 2001. The records are weighted to independent control counts of all births received in State vital statistics offices in 2001. Comparisons are made with 2000 final data. RESULTS: The number of births, the crude birth rate, and the fertility rate all declined slightly between 2000 and 2001. The number of births was down by less than 1 percent, the crude birth rate declined 1 percent to 14.5 per 1,000 population, and the fertility rate was down slightly to 67.2 births per 1,000 women aged 15-44 years. Teenagers were less likely to give birth in 2001; the teen birth rate continued to fall, dropping 5 percent between 2000 and 2001 to 45.9 births per 1,000 females aged 15-19 years, another record low. The teen birth rate has fallen 26 percent since 1991. The birth rate for teenagers 15-17 years fell 8 percent, and the rate for teenagers 18-19 years was down 4 percent for 2000-2001. Since 1991 rates have fallen 35 percent for teenagers 15-17 years, and 20 percent for teenagers 18-19 years. Birth rates for women aged 20-24 declined by 2 percent, whereas rates for women 25-44 years increased. Childbearing among women aged 40-54 years was stable. The birth rate for unmarried women decreased modestly to 44.9 births per 1,000 unmarried women 15-44 years in 2001, still remaining below the peak reached in 1994. The number of births to unmarried women was up very slightly, but births to unmarried teens were down. The proportion of women who began prenatal care in the first trimester of pregnancy improved slightly to 83.4 percent, but the rate of low birthweight held at 7.6 percent. The total cesarean delivery rate jumped 7 percent between 2000 and 2001 to 24.4 percent of all births, the highest level ever reported from this data source; the primary rate of cesarean deliveries rose 5 percent, and the rate of vaginal births after previous cesarean delivery tumbled 20 percent.     

Births: preliminary data for 2002.

OBJECTIVES: This report presents preliminary data for 2002 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, prenatal care, cesarean delivery, preterm births, and low birthweight are also presented. METHODS: Data in this report are based on nearly 98 percent of births for 2002. The records are weighted to independent control counts of all births received in State vital statistics offices in 2002. Comparisons are made with 2001 final data. RESULTS: The crude birth rate was 13.9 per 1,000 population in 2002, a decrease of 1 percent from 2001 (14.1). This is the lowest birth rate reported for the United States since national data have been available. The fertility rate was also down 1 percent in 2002 to 64.8 births per 1,000 women aged 15-44 years. Since 1990, this rate has declined 9 percent. The birth rate for teenagers continued to decline in 2002, dropping 5 percent to 42.9 births per 1,000 women aged 15-19 years. The teenage birth rate has dropped 28 percent since 1990. The rate for younger teenagers 15-17 years fell 6 percent from 24.7 per 1,000 in 2001 to 23.2 in 2002. The rate for older teenagers 18-19 years declined 4 percent from 76.1 per 1,000 in 2001 to 72.7 in 2002. Since 1990, the rate for teenagers 15-17 years has fallen 38 percent and the rate for teenagers 18-19 years, 18 percent. The birth rate for women aged 20-24 years declined by 3 percent to 103.5 per 1,000 in 2002 compared with 2001, whereas the rate for women aged 25-29 years was essentially unchanged (113.6). The birth rate for women aged 30-34 years decreased slightly from 91.9 per 1,000 in 2001 to 91.6 in 2002. Birth rates for women aged 35-39 years and 40-44 years continued to rise, increasing 2 percent for both. Childbearing among women over 45 years of age was unchanged. The birth rate for unmarried women was down slightly in 2002 to 43.6 births per 1,000 unmarried women aged 15-44 years. The number of births to unmarried women increased by 1 percent in 2002; however births to unmarried teenagers declined by 4 percent. Prenatal care utilization continued to slowly but steadily improve; 83.8 percent of women began prenatal care in the first trimester of pregnancy in 2002 compared with 83.4 in 2001. More than one fourth of all births (26.1 percent) were cesarean deliveries in 2002, the highest rate ever reported in the United States; the primary cesarean rate jumped 7 percent to 18 percent and the rate of vaginal births after previous cesarean delivery plummeted 23 percent to 12.7 percent (figure 1). Preterm (12.0 percent) and low birthweight (7.8 percent) rates were up slightly for 2002. The low birthweight rate is the highest reported in more than three decades.     

Births: preliminary data for 2003.

OBJECTIVES: This report presents preliminary data for 2003 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, tobacco use, prenatal care, cesarean delivery, preterm births, and low birthweight are also presented. METHODS: Data in this report are based on nearly 99 percent of births for 2003. The records are weighted to independent control counts of all births received in State vital statistics offices in 2003. Comparisons are made with 2002 final data. RESULTS: The crude birth rate rose to 14.1 births per 1000 population in 2003, an increase of 1 percent from 2002 (13.9). The fertility rate also rose in 2003 by 2 percent to 66.1 births per 1000 women aged 15-44 years. Since 1994, the rate has ranged from 63.6 to 66.1. The birth rate for teenagers continued to decline in 2003 to 41.7 births per 1000 women aged 15-19 years, 3 percent lower than in 2002. Rates fell for teenagers in all race and Hispanic origin groups, in many cases marking new record lows for the Nation. Birth rates for teenagers 15-17 and 18-19 years continued to steadily decline. The rate for ages 15-17 was 22.4 per 1000 in 2003, down 3 percent from 2002 and 42 percent from 1991, the recent peak. The rate for older teenagers 18-19 years in 2003 was 70.8 per 1000, also 3 percent lower than in 2002 and 25 percent lower than in 1991. The birth rates for women in their twenties were 102.6 per 1000 for women aged 20-24 years and 115.7 for women aged 25-29 years, a decrease of 1 percent and an increase of 2 percent, respectively, compared with 2002. The birth rate for women aged 30-34 years increased 4 percent to 95.2 births per 1000 women compared with 2002. The rate rose 6 percent for women aged 35-39 years, between 2002 and 2003, and 5 percent for women aged 40-44 years. The rate for women aged 45-49 years remained unchanged. The birth rate for unmarried women increased by 3 percent in 2003, from 43.7 to 44.9 per 1000 unmarried women aged 15-44 years. The proportion of births to unmarried women also increased in 2003 to 34.6 percent, compared with 34.0 percent in 2002. The proportion of mothers smoking during pregnancy continued to steadily decline in 2003, from 11.4 percent in 2002 to 11.0 percent. The percent of women who received prenatal care within the first 3 months of pregnancy edged upward for 2003, to 84.1 percent, compared with 83.7 percent in 2002. In 2003, 27.6 percent of all births were delivered by cesarean delivery, a marked rise of 6 percent over the 2002 level, and one-third higher than that for 1996. The primary cesarean rate also rose 6 percent between 2002 and 2003 while the rate of vaginal birth after previous cesarean (VBAC) dropped by 16 percent. Preterm and low birthweight rates both rose between 2002 and 2003. The preterm rate increased from 12.1 to 12.3 and low birthweight rate rose from 7.8 to 7.9 percent.     

Births: preliminary data for 1999.

OBJECTIVES: 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 mother. Data on marital status, prenatal care, cesarean delivery, and low birthweight are also presented. METHODS: Data in this report are based on more than a 97-percent sample of births for 1999. The records are weighted to independent control counts of births received in State vital statistics offices in 1999. Comparisons are made with 1998 final data. RESULTS: The crude birth rate in 1999 was 14.5 per 1,000 population, a slight decline from 1998 (14.6), returning to the level observed in 1997. However, the fertility rate, which is limited to women aged 15-44 years, was 65.8 in 1999, a slight increase over the rate for 1998 (65.6). The birth rate for teenagers continued to decline for 1998-99, dropping 3 percent to 49.6 births per 1,000 females aged 15-19 years. The 1999 rate for teenagers is 20 percent lower than the recent high point in 1991. The rate for young teenagers 15-17 years fell 6 percent, and the rate for teenagers 18-19 years declined 2 percent. Since 1991, rates have fallen 26 percent for teenagers 15-17 years, and 15 percent for teenagers 18-19 years. Birth rates for women aged 20-24 years declined slightly between 1998 and 1999 whereas the rate for women aged 25-29 years rose 2 percent. Birth rates for women in their thirties and forties continued their long increase. Rates for women in their thirties increased 2 to 3 percent and were the highest in three decades. The birth rate for women aged 40-44 years was the highest level reported since 1970. The birth rate for unmarried women in 1999 was 43.9 per 1,000, 1 percent lower than in 1998 and 6 percent lower than the peak level reported for 1994 (46.9). However, the number of births to unmarried women was up about 1 percent due to the continued increase in the number of unmarried women of childbearing age. The rate of prenatal care utilization continued to improve. The total cesarean rate increased 4 percent between 1998 and 1999 and continued a 3-year rise. The low birthweight rate remained unchanged at 7.6 percent.     

Comparison of infant mortality among twins and singletons: United States 1960 and 1983

Infant mortality among US black and white twins and singletons was compared for 1960 and 1983 using the Linked Birth/Infant Death Data Sets from the National Center for Health Statistics. Both twin and singleton infant mortality rates showed impressive declines since 1960 but almost all of the improvement in survival for both twins and singletons was related to increased birth weight-specific survival rather than improved birth weight distribution. One-half of white twins and two-thirds of black twins weighed less than 2,500 g at birth, and 9% of white twin births and 16% of black twin births were in the very low (less than 1,500g) birth weight category. In 1983, twin infant mortality rates were still four to five times that of singletons. However, twins had a survival advantage in the 1,250-3,000 g range, which persisted after adjustment for gestational age. Cause-specific mortality among twins was considerably higher for every major cause of death: twin mortality risks due to newborn respiratory disease, maternal causes, neonatal hemorrhage, and short gestation/low birth weight were six to 15 times that of singletons. The lowest twin-to-singleton mortality ratios observed were for congenital anomalies and sudden infant death syndrome with relative risks twice that of singletons. The data underscore the need to develop effective strategies to decrease infant mortality among twins.     

Perinatal mortality in single and multiple births in Japan, 1980–1991

Summary. Perinatal mortality rates (PMR) decreased significantly per year in single, twin, triplet, quadruplet and quintuplet births during the period 1980–1991. The PMRs were 7.7 per 1000 livebirths for singletons, 45.6 for twins, 89.0 for triplets, 116.8 for quadruplets, and 476.2 for quintuplets during the 12 years. The relative risks of perinatal death in multiplets vs. singletons were 6 for twins, 12 for triplets, 15 for quadruplets and 62 for quintuplets. The PMR was significantly higher in males than females for singletons and twins, but there was no sex differential in PMRs for higher order of multiple births. The PMR increased with birth order in twins and triplets, whereas there was no birth order effect on the PMR for quadruplets. An increasing proportion of multiple births among perinatal deaths may be related to the increasing multiple birth rate in Japan.