![(spacer)](https://webarchive.library.unt.edu/eot2008/20090113211739im_/http://olpa.od.nih.gov/images/_blank.gif) |
108th Congress
Session I | Session II
Testimony Before the Subcommittee on Children and Families, Committee on Health, Education, Labor and Pensions
Duane F. Alexander, M.D.
Director
National Institute of Child Health and Human Development
National Institutes of Health
May 13, 2004
Good morning. I am Duane Alexander, Director of the National Institute of Child Health and
Human Development (NICHD) at the National Institutes of Health (NIH). I am pleased to be
here to talk about the critical health challenge of prematurity.
Last year, during our celebration of the 40th anniversary of the Institute, we had an
opportunity to take stock of our efforts to advance research in the fields that fall within our
mission. Infant mortality is a major index of a nation’s health, yet the infant mortality rate in
the United States remains far higher than it should be, given the advantages we have
compared to many countries with lower rates. We were gratified to realize that since the
founding of NICHD, infant mortality rates in the United States have dropped more than 70
percent (to an all-time low of 6.8 per 1,000 live births in 2001), with much of this decline
resulting from NICHD-sponsored research on care of low birth weight infants, Sudden
Infant Death Syndrome, and other factors. For example, resulting from the research efforts
of NICHD and other Institutes, survival rates for very premature infants with respiratory
distress syndrome have gone from five percent in the 1960s to 95 percent today, due to
advances in respirator technologies and the availability of replacement lung surfactant.
Sadly, even with these important accomplishments, we are still far from solving the
problem of prematurity. Preterm birth (before 37 weeks of gestation) poses great risks to
the infant. At least one in eight infants – about 476,000 -- is born prematurely in the United
States each year. Over the last twenty years, preterm birth in this country has actually
increased by 21 percent. Preterm birth is the leading cause of death among African-
American infants, contributing substantially to racial and ethnic health disparities in infant
mortality, and is one of the top causes of all neonatal and infant deaths. In addition,
preterm babies are more likely to have long-term health problems, such as a higher
incidence of developmental disabilities. Premature delivery accounts for one of five
children born with mental retardation, one of three who have some visual impairment, and
almost half of those babies with cerebral palsy. Over the longer term, for the baby, for
reasons we cannot explain, preterm birth carries with it an increased risk for
cardiovascular disease and diabetes as an adult. For the mother, not only is preterm labor
a leading cause of hospitalization of women, but she faces a greatly increased risk of
delivering prematurely in the future.
Few other medical challenges fall so squarely within the mission of the NICHD, which is “to
assure that every individual is born healthy and wanted, that women suffer no adverse
consequences from the reproductive process, and that all children have the opportunity to
fulfill their potential for a healthy and productive life unhampered by disease or disability.”
We are focusing on prematurity using every mechanism at our disposal, including
investigator-initiated grant applications from scientists across the country, our own
requests for grant proposals in specific areas, conferences and workshops, and most of
all, our multi-center networks – the Maternal-Fetal Medicine Units, which deliver about
120,000 babies each year, and the Neonatal Network, which cares for about 60,000
babies every year. As you can see, the numbers of pregnant women and infants we are
able to care for at these hospitals, staffed by some of the leading clinician-researchers in
the field working collaboratively, gives us an opportunity to quickly and thoroughly test new
preterm delivery prevention and management strategies.
Until recently, most previously tested strategies to prevent preterm birth in high-risk women
failed to produce effective, reliable results because too few patients were studied and
conditions were not well controlled. The Maternal-Fetal Medicine Network was established
to overcome these problems. In one of the few concrete breakthroughs on this
tremendously difficult front, published in the New England Journal of Medicine in 2003, we
reported that our scientists who participate in the MFMU network had demonstrated that
weekly injections of 17-hydroxy-progesterone, can reduce preterm birth by one-third
among women at increased risk of preterm delivery because they had previously had a
preterm delivery. Not only were the women treated with progesterone 30 percent more
likely to carry their babies to term, their infants also had a much lower rate of life-
threatening complications. The 463 women involved in the study were considered to be at
high risk for preterm birth because they each had previously spontaneously delivered a
baby early, at an average of about 31 weeks. As in many clinical trials, some of the
women enrolled received the hormone being tested (the progesterone), while some
received a placebo injection. The reduction in preterm birth – for African American women
as well as non-African American women -- was so dramatic that the scientists halted the
study early to make the results available to practitioners. Shortly thereafter, a committee of
the American College of Obstetricians and Gynecologists notified its members of the
success of this trial, recommending that women who had had a previous preterm delivery
be considered for treatment with progesterone.
Let me talk for a moment about preventing preterm labor, one of the best ways to reduce
the numbers of preterm births. Over the years, we have supported a range of studies to
examine the effectiveness of various preventive measures for preterm labor, and this
research has revealed some surprises. For instance, studies have shown that bed rest,
which until very recently was the most common preventive approach, was not effective in
preventing preterm labor or in delaying preterm birth. In some cases, bed rest may have
actually made the situation worse. One possible explanation for these findings may be that
active pregnant women are better able to expand their blood volume, which is necessary
for a successful, full-term pregnancy. Other studies have examined the effectiveness of
different drugs in suppressing uterine contractions early in preterm labor, although no
effective treatment has yet been identified. Yet another Maternal-Fetal Medicine Network
trial demonstrated that Home Uterine Activity Monitoring, an expensive, highly touted
regimen claimed to reduce preterm delivery, was completely ineffective for this purpose,
thereby saving money and wasted effort by ending this useless practice.
Many NICHD-supported studies have been trying to answer the basic question of why
women with no known risks experience preterm labor. During the course of these studies,
researchers noted a relationship between bacterial vaginosis and preterm labor. In 1999,
NICHD completed a large study that recruited pregnant women who had asymptomatic
bacterial vaginosis to explore this possible association and results of treatment for it.
Although the study found no difference in preterm labor between women who received an
antibiotic and women who received the placebo, the research provided important clues
about other possible treatments. It also stopped the growing practice of treating women
who have asymptomatic bacterial vaginosis with antibiotics unnecessarily. Scientists at
other institutes are looking for other clues to the cause of preterm labor. For example, the
National Institute of Environmental Health Sciences is supporting research on whether
exposure to certain environmental contaminants during pregnancy relates to preterm birth.
In addition, NICHD’s newest intramural branch, the Perinatology Research Branch, is
devoted to the study of premature birth and its consequences. Among other
developments, the Branch has provided evidence that many premature newborns were
critically ill prior to birth due to intrauterine infection, and is exploring the role of premature
delivery in order to help these babies receive earlier treatment in order to survive.
We were able to rule out bacterial vaginosis as a direct cause of prematurity, and building
on the progress we have made, we will conduct more research on understanding the
causes of this condition, how we can prevent and treat prematurity in pregnant women, and
further work on how best to manage or treat newborns who have been born prematurely.
Thank you for the opportunity to discuss NICHD’s research on prematurity and for your
interest in this important topic. I am happy to answer any questions you may have.
|
![(spacer)](https://webarchive.library.unt.edu/eot2008/20090113211739im_/http://olpa.od.nih.gov/images/_blank.gif) |