day 1 in 8 babies born in the U.S. arrives too soon. Premature birth can
happen to any pregnant woman, and no one knows why. It is a serious,
common and costly problem.
March of Dimes is leading the campaign to reduce
premature birth by supporting research and by educating the public
and health care providers.
has been escalating steadily and alarmingly over the past two decades. Between
1981 and 2002, the rate of premature births rose from 9.4 percent to 12.1,
an increase of more than 29 percent. Every year more than
470,000 infants are born prematurely. That's roughly comparable
to the population of New Orleans or Cleveland.
Preterm delivery can happen to any pregnant woman. It's
happening more and more often. And, in nearly half the cases, no one
1,300 babies in the U.S. will be born prematurely. Many will be too small
and too sick to go home. Instead, they face weeks or even months in
the neonatal intensive care unit (NICU), with their frightened parents
looking on helplessly. These babies face an increased risk of death and
serious medical complications; however, most, eventually, will go home.|
But what does the future hold for these babies? Many survivors grow
up healthy; others arenít so lucky. Even the best of care cannot
always spare a premature baby from lasting disabilities such as cerebral
palsy, mental retardation and learning problems, chronic lung disease, and
vision and hearing problems. Half of all neurological disabilities
in children are related to premature birth.
While doctors have made tremendous advances in caring for babies born too
small and too soon, we need to find out how to prevent these tragedies
from happening in the first place. Despite decades of research,
scientists have not yet developed effective ways to help prevent premature
delivery. In fact, the rate of premature birth increased 29 percent
between 1981 and 2002 (9.4 to 12.1 percent).
Do Women Deliver Early?
nearly half of premature births, the cause is unknown. However,
researchers have made some progress in learning the causes of prematurity.
Studies suggest that there may be four main routes
leading to premature labor.
- Maternal or fetal stress.
Chronic psychosocial stress in the mother or physical stress (such as
insufficient blood flow from the placenta) in the fetus appears to
result in production of a stress-related hormone called corticotropin-releasing
hormone (CRH). CRH may stimulate production of a cascade of
other hormones that trigger uterine contractions and premature
- Infections. Studies suggest
that premature labor is often triggered by the bodyís natural immune
response to certain bacterial infections, such as those involving the
genital and urinary tracts and fetal membranes. Even infections
far away from the reproductive organs, such as periodontal disease,
may contribute to premature delivery.
- Bleeding. The uterus may
bleed, due to problems such as placental abruption (when the placenta
peels away, partially or almost completely, from the uterine wall
prior to delivery). Bleeding triggers the release of various
proteins involved in blood clotting, which also appear to stimulate
- Stretching. The uterus may
become overstretched by the presence of two or more babies, excessive
amounts of amniotic fluid, or uterine or placental abnormalities,
leading to release of chemicals that stimulate uterine contractions.
The finding that there are several routes that can
result in premature delivery may help explain why prematurity is so
difficult to prevent. Now that scientists have a better handle on
possible pathways to prematurity, they may be able to develop more
effective interventions that can halt the various chemical cascades that
lead to it. But first they must identify the women who need these
more information, visit The March of Dimes
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