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Pre-Eclampsia Is on the Rise in the U.S.

Obstetrics: Researchers are getting closer to discovering the causes of the condition dangerous to mothers and fetuses.

March 19, 2001|LAURAN NEERGAARD | ASSOCIATED PRESS

WASHINGTON — 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 what causes 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% 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 that 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 women 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.

Although only a few hundred American women a year die from pregnancy-related problems, pre-eclampsia does account for 16% of maternal deaths. In developing countries where babies can't be delivered early or seizures treated with magnesium, as in the U.S., 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 whether the substance, linked to heart attacks in older people, actually increases pre-eclampsia risk and, if so, whether B vitamins such as 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, such as a rise in blood pressure.

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