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Monday, Oct. 11, 2004
The birth of a newborn IS usually
a joyful event in the life of a family. The memory of nine
often uncomfortable months not
to mention the intense effort of labor and delivery begins
to fade and the focus shifts to a wrinkled little miracle with
10 impossibly cute fingers and toes. Everyone is trying to
decide whether the baby looks more like Mom or Dad. There are
smiles all around, and in a day or two the happy family will
leave the hospital to begin a grand new adventure at home.
Thankfully, this enchanting scenario remains the case most
of the time. But the odds of a healthy start in life quickly
begin to fall whenever a baby is born more than a few weeks
shy of the typical 40-week-long pregnancy.
Premature birth by
which doctors mean at least three weeks early is the leading
cause of developmental disability in children, including cerebral
palsy and mental retardation, according to Dr. Eve Lackritz
of the National Center for Chronic Disease Prevention and Health
Promotion. It is also a significant cause of blindness, chronic
lung problems and birth defects.
Yet, for a combination of
reasons not all of them clear 1 out of 8 babies in the
U.S. is born at least three weeks before it is due. Even more
alarming,
that ratio represents a 27% increase since 1980. Advances in
neonatal care have saved many children who might otherwise
have died. And lots of babies who leave the intensive-care
unit grow up to be healthy, vibrant adults. But no incubator no
matter how high tech will ever replace the womb. The goal,
as doctors and nurses who treat ultrafragile preemies will
tell you, should be to keep infants from ever needing extraordinary
measures in the first place.
Much of the jump in premature
births in the U.S. can be tied to the growing number of multiple
births twins, triplets or more that result from infertility
treatments. If you have one baby, your chance of delivering
prematurely is just over 10%, according to Dr. Charles Lockwood
at Yale University, and your chance of delivering what is called
a very preterm baby (one born before 32 weeks) is less than
2%. But if you have twins, the most recent federal data show,
your chance of preterm delivery jumps to 58%, with a 12% chance
of very early delivery. With triplets, you have almost no chance
of reaching full term and a 60% chance of delivering before
32 weeks.
Specialists in the U.S. often transfer several embryos
into the womb during in vitro fertilization (IVF) in hopes
of boosting the chance that one of them will "take" and therefore
boost their clinic's success rate. Studies suggest, however,
that the odds of a successful pregnancy may be the same whether
you implant one, two or three embryos. Many European countries
have decided to restrict their IVF clinics to one or two embryos
per pregnancy. Dr. Lockwood and other physicians think such
a limit might make sense in the U.S. as well.
Assisted reproduction
isn't the only problem. Doctors have long known that smoking,
uterine infection, high blood pressure and a prior history
of preterm delivery also place an expectant mother at greater
risk of delivering early. They're looking into the possibility
that other factors, such as stress, diet (both before and after
conception) and inflammation may also play a role. But they
have something of a medical mystery on their hands. "Nearly
half of preterm births are from unclear causes," says Dr. Nancy
Green, medical director of the March of Dimes, which is in
the early stages of a five-year, $75 million campaign to address
the issue. You can do everything right and still give birth
to a premature baby.
Doctors admit that some of their best
ideas for preventing early delivery haven't worked very well.
A drug called Ritodrine, which was approved by the Food and
Drug Administration in 1980, successfully stops preterm labor
in many women, but subsequent studies have shown that it has
no overall effect on a baby's health or survival. Treating
all uterine infections, no matter how mild, also appears to
make no difference on the timing of delivery suggesting that
infection is only one stage in a larger, much more complex
process. "We've been taking the one-cause-at-a-time approach
for 20 years," says Dr. Jay Iams at Ohio State University in
Columbus. "But it doesn't work that way." Indeed, many researchers
believe they won't really have a good grasp of how to prevent
prematurity until they answer an even more fundamental question:
How does a woman's body decide it's time to give birth in the
first place?
One intervention has shown some promise in early
trials of women with a history of premature delivery and no
other known risk factors. Injecting these women once a week
with the hormone progesterone reduces their chance of delivering
early by a third. Researchers still don't quite understand
why it works. The placenta produces a lot of the hormone, so
it wouldn't seem that adding a little more would make a big
difference. The treatment has not been studied in women who
are carrying more than one child.
Caution may be in order.
No one wants a repeat of the problems that happened with diethylstilbestrol
(DES), a synthetic estrogen-like drug that was used in the
1950s and '60s to prevent premature delivery and turned out
to cause, among other things, reproductive-tract abnormalities
and a rare cancer. Unlike DES, however, progesterone has a
long safety record. And it is not being used in the earliest
days of pregnancy, when birth defects are more likely to occur.
What progesterone doesn't have is a major manufacturer, because
the drug is not protected by a patent. Instead it is usually
produced in small batches at compounding pharmacies.
Anyone
who has ever cared for an extremely premature infant knows
the stakes are high. Doctors can sustain a tiny baby with severe
bleeding in the brain, with lungs so fragile that even the
gentlest respirator can permanently damage them. But should
they? "That's when neonatology becomes a difficult and ethically
fraught field," says Dr. Myra Wyckoff of the University of
Texas Southwestern Health Science Center in Dallas. No matter
how you answer the question, surely the best solution is to
find a way to reduce the number of extremely premature births
from happening in the first place.
Reported by Anna Macias Aguayo/Dallas; David Bjerklie/New
York; Paul Cuadros/Chapel Hill N.C.; Leslie Whitaker/Chicago
Copyright ฉ 2004
Time Inc.
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