Multiple Births in United States in 2010:

  Births: Final Data for 2010

From the CDC (Centers for Disease Control and Prevention) website.

This is the most recent data on birth rate and associated trends in the United States.  To view the entire report, visit. http://www.cdc.gov/nchs/data/nvsr/nvsr60/nvsr60_01.pdf

Below are general highlights of the major statistics from this report, followed by the Multiple Birth information from 2010.  Please refer to the full report for figure and table references.

Births in 2010

A total of 3,999,386 births were registered in the United States, 3 percent less than in 2009 (4,130,665) and 7 percent less than the record number of births in 2007 (4,316,233). The absolute decline in the number of births from 2009 to 2010 (131,279) is the largest single-year decline since 1971–1972 (4).

The number of births declined for nearly all of the race and Hispanic origin groups in 2010, down 2 percent for non-Hispanic white, 3 percent for non-Hispanic black, and 5 percent for Hispanic women. Births also declined for API (2 percent) and AIAN (4 percent) women in 2010. Births to each of the specified Hispanic groups also declined (3 percent to 4 percent for Puerto Rican and Central and South American women, and 7 percent for Mexican women); the number of births to Cuban women was essentially unchanged.

Birth rates declined among women of all age groups under age 40 from 2009 to 2010; the rate for women aged 40–44 rose and the rate for women aged 45–49 was unchanged.

Childbearing by teenagers fell to historic lows in the United States in 2010. The overall birth rate dropped 10 percent during 2009–2010, from 37.9 to 34.2 per 1,000 women aged 15–19. Since 1991, when the current long-term decline began, the rate has fallen 45 percent. The number of births to women aged 15–19 dropped 10 percent as well, to 367,678, the fewest in more than six decades (322,381 in 1946). A recent analysis found that if the 1991 teen birth rates had prevailed from 1992 through 2010, an additional 3.4 million births to women aged 15–19 in the United States would have occurred (12).

Rates have dropped significantly for teenagers in all age sub­ groups and the rates in 2010 were record lows. The birth rate for the youngest girls fell to 0.4 per 1,000 aged 10–14 (from 0.5 in 2009). The rate for teenagers 15–17 dropped 12 percent in 2009–2010, from 19.6 to 17.3 per 1,000, while the rate for older teenagers declined 9 percent from 64.0 to 58.2 per 1,000.

Teen birth rates by race and Hispanic origin continue to reflect wide disparities. Rates remained highest in 2010 for Hispanic (55.7 per 1,000 aged 15–19) and non-Hispanic black (51.5) teenagers, followed by AIAN (38.7), non-Hispanic white (23.5), and API (10.9) teenagers. Still, rates fell markedly for all groups aged 15–17 and 18–19. For the most recent 3-year period 2007–2010, birth rates declined 16 percent for non-Hispanic white teenagers aged 15–17 and 18–19, 19–23 percent for non-Hispanic black and AIAN teenagers, and 25–31 percent for Hispanic and API teenagers.

A recently published report of pregnancy estimates found that the long-term declines in teen birth rates have coincided with declines in teen pregnancy, abortion, and fetal loss rates (13). Between 1991 and 2008, the most recent year for which pregnancy estimates are avail­ able, the teenage pregnancy rate fell 40 percent to 69.8 per 1,000 women aged 15–19, the lowest ever in the more than three decades for which a national series of rates is available (13,14). All components of the pregnancy rate fell during the period 1991–2008: the birth rate by 35 percent, the abortion rate by 52 percent, and the fetal loss rate by 31 percent.

The long-term declines in teen birth rates have been linked to the strong pregnancy prevention messages directed to teenagers (15–17). Recently released data from the 2006–2010 National Survey of Family Growth (NSFG) conducted by NCHS have shown increased use of contraception at first intercourse and use of dual methods of contraception (that is, condoms and hormonal methods) among sexually active male and female teenagers. These trends have likely contributed to the recent birth rate decline (18).

MULTIPLE BIRTHS 2010

The twin birth rate declined slightly in 2010 to 33.1 per 1,000 total births, from 33.2 in 2009. The twinning rate climbed steadily, by 76 percent from 1980 to 2009. Rates rose nearly 3 percent a year during the 1990s, but the pace of increase had slowed to less than one-half of 1percent annually since the mid-2000s (40). There were 132,562 births in twin deliveries in 2010, a 3 percent decline from 2009, similar to the percent decline in the number of singleton births.

The rate of triplet/+ births declined 10 percent in 2010 to 137.6 per 100,000 births from 153.5 in 2009. The 2010 rate is the lowest in 15 years (1995). The triplet/+ birth rate (number of triplets, quadruplets, and quintuplets and other higher-order multiples per 100,000 births) rose more than 400 percent during the 1980s and 1990s, but has declined 29 percent since the 1998 peak (193.5). The 2010 number of triplet/+ births (5,503) was the lowest reported since 1995 and includes 5,153 triplets, 313 quadruplets, and 37 quintuplets and higher-order multiples.

Twinning rates declined among non-Hispanic black women (from 38.0 to 37.0 per 1,000) from 2009 to 2010, but were not significantly changed among non-Hispanic white (36.9 in 2010) and Hispanic (22.6) women. During 1990–2009, rates rose 62 percent for non- Hispanic white, 42 percent for non-Hispanic black, and 25 percent for Hispanic women.

The triplet/+ birth rate for non-Hispanic white women declined 12 percent in 2010 to 177.7 per 100,000, from 201.4 in 2009; triplet/+ birth rates for non-Hispanic black (97.3 in 2010) and Hispanic (76.3) women did not change significantly. From 1990 through 1998, the triplet/+ rate for non-Hispanic white women rose nearly threefold, but has declined by nearly one-third since. Triplet/+ rates for non-Hispanic black women have fluctuated, but were down from 2005, whereas rates for Hispanic triplets showed no consistent recent trend.

From 2009 to 2010, triplet/+ birth rates declined by 10 percent or more for women in each age group within those aged 25–39. Since 1998, when the overall triplet/+ birth rate peaked, rates have declined by one-third or more for women aged 30 and over. Not shown is the change in the triplet/+ rate for women aged 45–54, which also declined by about one-third over this period (from 2,326 to 1,527 per 100,000).

The pronounced rise in multiple birth rates during the 1980s and 1990s has been associated with two related factors: older maternal age and the expanded use of fertility-enhancing therapies, both assisted reproductive technologies (ART) [e.g., in-vitro fertilization (IVF)], and non-ART treatments (ovulation induction medications without ART) (41,42). The recent decline in triplet/+ birth rates has been associated with practice guidelines from the American Society.

Numbers of twin, triplet, quadruplet, and quintuplet and other higher order multiple births: United States, 1995-2010

*Quintuplets, sextuplets and higher order multiple births are not differentiated in the national data set.

Multiple births, 2010

The twin birth rate declined slightly in 2010 to 33.1 per 1,000 total births, from 33.2 in 2009. The twinning rate climbed steadily, by 76 percent from 1980 to 2009. Rates rose nearly 3 percent a year during the 1990s, but the pace of increase had slowed to less than one-half of 1percent annually since the mid-2000s (40). There were 132,562 births in twin deliveries in 2010, a 3 percent decline from 2009, similar to the percent decline in the number of singleton births.

The rate of triplet/+ births declined 10 percent in 2010 to 137.6 per 100,000 births from 153.5 in 2009. The 2010 rate is the lowest in 15 years (1995). The triplet/+ birth rate (number of triplets, quadruplets, and quintuplets and other higher-order multiples per 100,000 births) rose more than 400 percent during the 1980s and 1990s, but has declined 29 percent since the 1998 peak (193.5). The 2010 number of triplet/+ births (5,503) was the lowest reported since 1995 and includes 5,153 triplets, 313 quadruplets, and 37 quintuplets and higher-order multiples.

Factors Affecting the Twinning Rate

Twinning rates declined among non-Hispanic black women (from 38.0 to 37.0 per 1,000) from 2009 to 2010, but were not significantly changed among non-Hispanic white (36.9 in 2010) and Hispanic (22.6) women. During 1990–2009, rates rose 62 percent for non- Hispanic white, 42 percent for non-Hispanic black, and 25 percent for Hispanic women.

The triplet/+ birth rate for non-Hispanic white women declined 12 percent in 2010 to 177.7 per 100,000, from 201.4 in 2009; triplet/+ birth rates for non-Hispanic black (97.3 in 2010) and Hispanic (76.3) women did not change significantly. From 1990 through 1998, the triplet/+ rate for non-Hispanic white women rose nearly threefold, but has declined by nearly one-third since. Triplet/+ rates for non-Hispanic black women have fluctuated, but were down from 2005, whereas rates for Hispanic triplets showed no consistent recent trend.

From 2009 to 2010, triplet/+ birth rates declined by 10 percent or more for women in each age group within those aged 25–39. Since 1998, when the overall triplet/+ birth rate peaked, rates have declined by one-third or more for women aged 30 and over. There was a change in the triplet/+ rate for women aged 45–54, which also declined by about one-third over this period (from 2,326 to 1,527 per 100,000).

The pronounced rise in multiple birth rates during the 1980s and 1990s has been associated with two related factors: older maternal age and the expanded use of fertility-enhancing therapies, both assisted reproductive technologies (ART) [e.g., in-vitro fertilization (IVF)], and non-ART treatments (ovulation induction medications without ART) (41,42). The recent decline in triplet/+ birth rates has been associated with practice guidelines from the American Society for Reproductive Medicine (43) intended to reduce the incidence of higher-order multiple gestation pregnancies, and to improvements in ART procedures, that is, the transfer of fewer embryos per IVF cycle (43).

For the years 2008–2010, most states reported twinning levels similar to the national of about 3 percent. In Connecticut, Massachusetts, and New Jersey, however, twins comprised 4 percent or more of all births. State-specific triplet/+ birth rates were highest (over 200 per 100,000 births) in Nebraska, New Jersey, and North Dakota; rates were lowest (less than 70 per 100,000) in Montana and New Mexico.

Infants born in multi-gestation pregnancies tend to be born earlier and smaller than those in singleton pregnancies. In 2010, more than 5 of every 10 twins, and 9 of 10 triplets were delivered preterm, compared with about 1 in 10 singletons (data not shown). Accordingly, multiples are at greater risk of early death; twins are about 5 times, and triplets 10 times as likely to die in infancy (30).