Study
Sheds Light On Cause Of Preeclampsia
Last
Months of Pregnancy Could Include Problem Related to High Blood Pressure
Among
the most serious of pregnancy complications is a condition known as
preeclampsia, a blood pressure-related problem that can develop in the
last trimester and threaten the life of both mother and baby.
Now
a group of British physicians say they might have a way of predicting
who is at risk for preeclampsia, long before symptoms occur.
In a new study appearing
in the the medical journal The Lancet, physicians from
Harris Birthright Centre, Kings College Hospital, London, say problems
appear linked to a dysfunction in the cells that line blood vessels
- called endothelial cells - and a natural chemical known as asymmetric
dimethylarginine (ADMA).
"Maternal endothelial
function is impaired in women who eventually develop preeclampsia, and
it occurs before the development of the clinical syndrome," writes
study author Kypros Nicolaides.
Predicting
Preeclampsia
Women
who are at risk for preeclampsia, he says, appear to have high concentrations
of ADMA. That chemical seems to contribute to the dysfunction of the
cells within blood vessel walls.
"The results
of this study may help the development of more accurate tests for the
prediction and more effective treatment of preeclampsia," says
Dr. Nicolaides.
While experts say
the study is well done and holds promise, according to obstetrician
Dr. Steve Farber, president of the medical staff at Maimonides Medical
Center in New York City, it is only one of many promising insights into
the cause of preeclampsia.
"With each
new study we find another piece of the puzzle, and we have a little
better understanding of this complex problem and why it occurs,"
says Dr. Farber.
And while he says
researchers have focused on the endothelial cells before, it remains
to be seen just how significant ADMA is the big picture, he says.
Although Dr. Farber
says finding this new information can lead to new hope in the future,
he adds that right now it does little to change the clinical picture
of preeclampsia since delivery still remains the only treatment option.
Preeclampsia is
characterized by a swelling that can occur throughout the body, usually
accompanied by a rapid rise in blood pressure. It normally begins late
in the third trimester and affects 7 percent to 10 percent of all pregnant
women, particularly older mothers or those carrying twins or triplets.
In some instances,
preeclampsia can develop into the more severe condition known as eclampsia,
causing a potentially fatal swelling in the brain.
Dr. Farber says
women and their physicians are often forced to play a difficult waiting
game, hoping to give the baby enough time to fully develop within the
womb, but still delivering early enough to avoid eclampsia.
Clues
Provide Hope
The new study involved
two groups of 43 pregnant women who had a Doppler ultrasound examination
of the uterus (a test that documents blood flow) in their second trimester,
while blood tests checked levels of ADMA.
In the first group
of 43, the women were shown to have normal uterine arteries and no elevations
in ADMA. Subsequently, they all delivered normally with no complications.
In the second group
of 43, the Doppler exam revealed impaired blood flow between the uterus
and the developing baby. Of this group, 44 percent went on to have normal
pregnancies and healthy births. In 33 percent of these women, however,
babies developed intrauterine growth restriction, putting them at risk
for low birth weight.
The remaining 23
percent developed preeclampsia. Because the Doppler exams revealed abnormal
blood flow within the uterine arteries, as well as abnormal blood vessel
dilation, researchers suggest arterial dysfunction as a factor in the
development of preeclampsia.
More importantly,
the women at risk for either preeclampsia or intrauterine growth restriction
also had what researchers call a "striking elevation" in the
concentration of ADMA in their blood. They say this substance may one
day serve as a marker for women at risk.
Always consult your
physician for more information.
What
Is Preeclampsia?
Preeclampsia, also
called toxemia, is a condition characterized by pregnancy-induced high
blood pressure, protein in the urine, and swelling due to fluid retention.
Eclampsia is the
more severe form of this condition, which can lead to seizures, coma,
or death.
The cause of preeclampsia
is unknown, but it is more common in first pregnancies. It affects about
7 percent to 10 percent of all pregnant women. Other risk factors for
preeclampsia include the following:
- a
woman carrying multiple fetuses
-
a teenage mother
-
a woman older than 40
-
a woman with pre-existing high blood pressure, diabetes, and/or
kidney disease
Symptoms may include
severe swelling of the hands and face, high blood pressure, headache,
dizziness, irritability, decreased urine output, abdominal pain, and
blurred vision.
Treatment will
vary according to the severity of the condition and the stage of the
pregnancy. Treatment may include hospitalization, bedrest, medication
to lower the blood pressure, and close monitoring of both the fetus
and the mother.
Online
Resources
American
College of Gastroenterology
American
College of Obstetricians and Gynecologists
American
Society for Reproductive Medicine
Centers
for Disease Control and Prevention (CDC)
Colon
Cancer Alliance
National
Cancer Institute (NCI), part of NIH
National
Institute of Child Health and Development (NICHD)
National
Institutes of Health (NIH)
National
Women's Health Information Center |
June 2003
In
This Issue:
Study
Sheds Light On Cause Of Preeclampsia
Predicting
Preeclampsia
Clues
Provide Hope
What
Is Preeclampsia?
Study:
High-Fiber Diet Helps Prevent Colon Cancer
What
Are the Symptoms of Colorectal Cancer?
Online
Resources
Other
Resources:
Find
a St. John's Mercy Physician
Women's
Services at St. John's Mercy
Women's
Health Information
St.
John's Mercy Classes and Programs
Study:
High-Fiber Diet Helps Prevent Colon Cancer
In the latest evidence pointing to the benefits of eating fiber, researchers
on both sides of the Atlantic report a high-fiber diet reduces the
risk of colon cancer.
That
conclusion, reported in two studies published in the medical journal
The Lancet, reinforces earlier medical advice recommending
high-fiber diets.
Other
studies in recent years, however, have found high-fiber diets provided
no protection against colon cancer, calling into question long-held
beliefs.
In
the European study, which the researchers called the largest ever
on the relationship between diet and cancer, the scientists tracked
more than one-half million people in 10 countries for an average of
4 and one-half years.
Those
who averaged 35 grams of daily fiber intake had a 25 percent lower
risk of colorectal cancer, primarily colon cancer, compared with those
who averaged 15 grams of fiber a day, the study found.
"The
most interesting thing is, it does actually confirm all the other
studies prior to the most recent ones," which found no relationship
between high-fiber diets and cancer, says Dr. Sheila A. Bingham, the
lead author of the European study.
"Eat
more plant foods because then you're eating more whole-grain cereal,
more fruits and vegetables - that's the message coming through,"
adds Dr. Bingham, at the UK Medical Research Council's Dunn Human
Nutrition Unit in Cambridge.
The
US study focused on 37,600 people, about 3,600 of whom had non-malignant
polyps - precursors to colon cancer. The researchers divided the participants
into five groups according to their fiber consumption.
Those
who ate the most fiber, an average of 36.4 grams a day, had a 27 percent
lower risk of the polyps than those who ate the least fiber, averaging
12.6 grams a day, the study found.
To
achieve those protective effects, the latest research suggests, Americans
would have to consume much more fiber than they currently do. The
US study shows Americans average about 16 grams of fiber a day.
"You
really can see the risk [of colon cancer] is going down when the fiber
is increasing; it's a very strong trend," says Dr. Ulrike Peters,
the lead author of the US study. "This is a positive finding
because it is consistent with health recommendations" for fiber
intake, adds Peters, a researcher at the National Cancer Institute
(NCI).
Both
studies looked at fiber in foods only, drawing no conclusions about
the potential protective value of fiber in dietary supplements.
Dr.
Bingham suggests earlier research could have mistakenly concluded
fiber had no preventive effect because of smaller amounts of fiber
eaten and less variety in the amounts and types.
But
Dr. M. Robert Cooper, the principal investigator of the 2000 Polyp
Prevention Trial, says he stands by its findings that a high-fiber
diet does not protect against colon cancer.
"It's
not a major factor in preventing colon cancer," Dr. Cooper says
of fiber. "We need to go on to something that's more significant
than fiber," he adds, calling for more emphasis on screening
for colon cancer.
Always
consult your physician for more information.
What
Are the Symptoms of Colorectal Cancer?
The
following are the most common symptoms of colorectal cancer. However,
each individual may experience symptoms differently.
People
who have any of the following symptoms should check with their physicians,
especially if they are over 50 years old or have a personal or family
history of the disease:
-
a
change in bowel habits such as diarrhea, constipation, or narrowing
of the stool that lasts for more than a few days
-
rectal bleeding or blood in the stool
-
cramping or gnawing stomach pain
-
decreased appetite
-
vomiting
-
weakness and fatigue
-
jaundice (yellowish coloring) of the skin or sclera of the eye
The symptoms of colorectal cancer may resemble other conditions, such
as infections, hemorrhoids, and inflammatory bowel disease. It is also
possible to have colon cancer and not have any symptoms.
Always
consult your physician for a diagnosis.
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