By LAURAN NEERGAARD AP Medical Writer
WASHINGTON
(AP)--One of the most dangerous and baffling complications of
pregnancy is increasing among American women, a condition called
pre-eclampsia that can be life-threatening to both mother and
fetus.
Doctors don't
know the cause or how to prevent pre-eclampsia _ and the only
cure is delivery, which can be risky depending on how premature
the baby is. And with more and more older mothers and multiple
births, the frightening condition isn't likely to diminish soon.
But long-frustrated
researchers are honing in on new clues to pre-eclampsia's underlying
causes--the telltale high blood pressure is actually a symptom--that
suggest they're getting close to cracking the mystery.
``It's not
out of the question that there will be some effective preventive
treatments in the next few years,'' says Dr. James M. Roberts
of Pittsburgh's Magee Women's Research Institute, who will head
a National Institutes of Health meeting next month to spur new
research.
Pre-eclampsia,
once known as toxemia or pregnancy-induced hypertension, fortunately
is fairly rare, affecting about 5 percent of pregnancies. But
the NIH just sounded an alarm that the pre-eclampsia rate rose
by nearly a third during the 1990s.
Pre-eclampsia
is diagnosed late in pregnancy with a sudden rise in blood pressure,
protein in urine, and swelling of the hands, face or feet. Other
signs are pain in the upper right abdomen, and headaches or visual
disturbances.
But those
are just late symptoms: Blood vessels are supposed to dilate in
early pregnancy as blood flow increases. Scientists now believe
a pre-eclamptic woman's vessels are constricted from the beginning,
reducing blood flow to the fetus and her own organs, thus potentially
causing kidney and other damage. Some women worsen to have seizures,
called eclampsia.
Some cases
are mild and mothers are prescribed bed rest in hopes of bringing
the baby to term. Severe cases may require an immediate Caesarean
section despite the risks of prematurity.
While only
a few hundred American women a year die from pregnancy, pre-eclampsia
does account for 16 percent of maternal deaths. In developing
countries that can't deliver babies early or treat seizures with
magnesium as U.S. doctors do, it kills thousands.
Why the rise?
At least part of the reason is more women delaying childbirth
until past age 35, and a rise in multiple births. Other risk factors
include: a first pregnancy, having high blood pressure before
pregnancy, a history of pre-eclampsia, and having diabetes, kidney
disease or certain blood-clotting disorders.
Even diagnosis
is difficult because many pregnant women suffer swelling or blood-pressure
rises totally unrelated to pre-eclampsia.
Once-touted
aspirin and calcium supplements failed to prevent the disorder.
Now, doctors are hunting other substances that may directly affect
blood vessels.
Roberts is
about to launch an NIH-funded study of 8,000 women to see if the
antioxidant vitamins C and E might prevent pre-eclampsia or lessen
its severity. British researchers suggested the vitamins could
work by blocking oxygen damage to blood vessels, but haven't proved
the effect or that high-dose vitamins are safe for developing
fetuses.
Roberts also
has found high levels of the amino acid homocysteine in pre-eclampsia
patients. He's studying if the substance, linked to heart attacks
in older people, actually increases pre-eclampsia risk and if
so, whether B vitamins like folic acid could help by decreasing
homocysteine.
Some scientists
even suspect pre-eclampsia's blood vessel problems could signal
women at risk for heart disease later in life. Still others suspect
an immune system role, perhaps a placental reaction to the father's
genes.
Whatever research
ultimately concludes, what should pregnant women today know? If
you're at increased risk for pre-eclampsia, don't skip any prenatal
visits, stresses Dr. Phyllis August of Cornell's Weill Medical
College, co-author of new federal guidelines on pre-eclampsia
diagnosis.
Those visits
are crucial to detect silent signs like blood pressure rises--and
be sure to tell your doctor about other symptoms like abdominal
pain.
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