National Academy of Sciences
National Academy of Engineering
Institute of Medicine
National Research Council
Office of News and Public Information
National Academy of Engineering
Back | Home
News from the National Academies

Read Full Report

Date:  July 13, 2006
Contacts:  Christine Stencel, Media Relations Officer
Maureen O'Leary, Director of Public Information
Christian Dobbins, Media Relations Assistant
Office of News and Public Information
202-334-2138; e-mail <news@nas.edu>

FOR IMMEDIATE RELEASE

Preterm Births Cost U.S. $26 Billion a Year;
Multidisciplinary Research Effort Needed to Prevent Early Births

WASHINGTON -- The high rate of premature births in the United States constitutes a public health concern that costs society at least $26 billion a year, according to a new report from the Institute of Medicine of the National Academies.  The report also notes troubling disparities in preterm birth rates among different racial and ethnic groups.  It recommends a multidisciplinary research agenda aimed at improving the prediction and prevention of preterm labor and better understanding the health and developmental problems to which preterm infants are more vulnerable.  In addition, the report recommends that guidelines be issued to further reduce the number of multiple births -- a significant risk factor for preterm birth -- resulting from infertility treatments.

The report uses the word "preterm" for births that occur at less than 37 weeks of pregnancy; a full-term pregnancy is 38 to 42 weeks.  In 2005, 12.5 percent of births in the United States were preterm, a 30 percent increase over 1981 rates.  Babies born before 32 weeks have the greatest risk of morbidity and mortality, but "near-term" or "late-preterm" infants born between 32 and 36 weeks, which make up the greatest number of preterm births, are still at higher risk for health and developmental problems than full-term newborns.  There is no test that accurately predicts preterm birth, and efforts to prevent it have primarily focused on delaying delivery long enough for the mother and fetus to get appropriate care, which has helped reduce morbidity and mortality rates.

"Despite great strides in improving the survival of infants born preterm, little is known about how preterm births can be prevented," said Richard E. Behrman, chair of the committee that wrote the report, and executive chair, Pediatric Education Steering Committee, Federation of Pediatric Organizations Inc., Menlo Park, Calif.  "Any significant gains to be made in the study of preterm birth will be in the area of prevention."

Last year the economic burden of preterm births was $26.2 billion, or $51,600 per infant, the committee estimated.  Most of the expense was for medical care, especially that provided in infancy.  Maternal care, early intervention services, special education for preterm infants with learning difficulties, and lost household and labor productivity also contribute to the cost.  Researchers should further investigate the economic consequences of preterm births so that a more accurate value can be placed on policies to prevent them, the committee recommended.

Researchers also should focus on studying how to prevent higher rates of preterm births among certain populations.  In 2003, 17.8 percent of pregnant black women gave birth to a preterm baby, compared with 10.5 percent of Asian women, 11.5 percent of white women, and 11.9 percent of Hispanic women.  Differences in socioeconomic conditions and maternal behaviors cannot fully account for these disparities, the committee noted.

More study also is needed of the causes and consequences of preterm births that occur because of infertility treatments, the report says.  The use of in vitro fertilization and other assisted reproductive technologies has risen dramatically in the past 20 years and has been associated with the trend to delay childbearing.  Twins, triplets, or even more fetuses often result in these cases because multiple embryos are implanted or because ovulation is promoted and more eggs are fertilized.  Among infants conceived using these methods, 61.7 percent of twins and 97.2 percent of triplets and other "higher-order" multiples were born preterm.  

In 1999, the American Society for Reproductive Medicine recommended limiting the number of embryos transferred to the womb.  A drop in the number of triplets in recent years seems to indicate that the recommendation is being followed, but there are still more multiple births here than in Europe.  The report recommends that the society join the American College of Obstetricians and Gynecologists as well as federal and state agencies in instituting new guidelines to reduce the number of multiple births.  Particular attention should be paid to the transfer of a single embryo and restricting the use of "superovulation" drugs.

A host of socioeconomic, biological, environmental, and other factors, often in combination, increase a woman's chances of preterm delivery.  Adolescents less than 16 years old are twice as likely as women over 18 to deliver preterm, and women 35 and older are also at increased risk.  And if a woman has delivered preterm, she is more likely to do so in future pregnancies as well.  Federal agencies should commit to sustained funding of research on the causes of preterm births, the report says.

Given that so many factors are involved, the National Institutes of Health and private foundations should establish integrated, multidisciplinary research centers to study the causes of preterm births and the outcomes for women and their children.  In addition, NIH should work with other agencies to develop guidelines for the reporting of more accurate data on outcomes.  In general, researchers should focus on better defining the problem of preterm birth and conducting studies that will inform public policy.

The IOM study was sponsored by the National Institute of Child Health and Human Development, U.S. Centers for Disease Control and Prevention, Health Resources and Services Administration, U.S. Environmental Protection Agency, NIH Office of Research on Women's Health, March of Dimes, Burroughs Wellcome Fund, American College of Obstetricians and Gynecologists, American Society for Reproductive Medicine, and the Society for Maternal-Fetal Medicine.  Established in 1970 under the charter of the National Academy of Sciences, the Institute of Medicine provides independent, objective, evidence-based advice to policymakers, health professionals, the private sector, and the public.  A committee roster follows. 
                        
Copies of Preterm Birth: Causes, Consequences, and Prevention will be available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu.  Reporters may obtain a pre-publication copy from the Office of News and Public Information (contacts listed above).

[ This news release and report are available at http://national-academies.org ]

INSTITUTE OF MEDICINE
Board on Health Sciences Policy

Committee on Understanding Premature Birth and Assuring Healthy Outcomes  

Richard E. Behrman, M.D., J.D. (chair)
Executive Chair
Pediatric Education Steering Committee
Federation of Pediatric Organizations Inc.
Menlo Park, Calif.

Eli Y. Adashi, M.D.
Dean of Medicine and Biological Sciences, and
Frank L. Day Professor of Biology
Brown University
Providence, R.I.

Marilee C. Allen, M.D.
Professor
Department of Pediatrics
Johns Hopkins University School of Medicine
Baltimore

Rita Loch Caruso, Ph.D.
Professor of Environmental Health Sciences and Associate Research Scientist
School of Public Health
University of Michigan
Ann Arbor

Jennifer Culhane, Ph.D., M.P.H.
Associate Professor
Department of Obstetrics and Gynecology
Drexel University College of Medicine
Philadelphia

Christine Dunkel Schetter, Ph.D.
Professor
Department of Psychology, Health, and Social Psychology
University of California
Los Angeles

Michael G. Gravett, M.D.
Professor and Vice-Chairman
Department of Obstetrics and Gynecology
University of Washington School of Medicine
Seattle

Jay D. Iams, M.D.
Professor and Vice Chairman
Department of Obstetrics and Gynecology
Ohio State University College of Medicine
Columbus

Michael C. Lu, M.D., M.P.H.
Assistant Professor
Department of Community Health Sciences
Department of Obstetrics and Gynecology
School of Medicine
University of California
Los Angeles

Marie C. McCormick, M.D., Sc.D.
Sumner & Esther Feldberg Professor of Maternal and Child Health
Department of Society, Human Development, and Health
Harvard School of Public Health
Boston

Laura E. Riley, M.D.
Director of Labor and Delivery, and
Director of Infectious Disease
Massachusetts General Hospital
Boston

Jeannette A. Rogowski, Ph.D.
Professor of Health Economics
Department of Health Systems and Policy
University of Medicine and Dentistry of New Jersey
New Brunswick

Saroj Saigal, M.D.
Professor of Pediatrics, and
Director
Neonatal Follow-up Program
McMaster University
Hamilton, Ontario
Canada

David A. Savitz, Ph.D.
Professor
Department of Community and Preventive Medicine
Mount Siani School of Medicine
New York City

Hyagriv N. Simhan, M.D.
Assistant Professor
Divisions of Maternal-Fetal Medicine and Reproductive Infectious Diseases and Immunology
Magee-Womens Hospital
University of Pittsburgh Medical Center
Pittsburgh

Norman J. Waitzman, Ph.D.
Associate Professor
Department of Economics
University of Utah
Salt Lake City

Xiaobin Wang, M.D., M.P.H., Sc.D.
Director and Mary Ann and J. Milburn Smith Research Professor
Children's Memorial Hospital and Children’s Memorial Research Center
Chicago

INSTITUTE STAFF

Adrienne Stith Butler, Ph.D.
Study Director