Childbirth raises risk of stroke, study says Survey covers women at 46 area hospitals who just delivered

September 12, 1996|By Diana K. Sugg | Diana K. Sugg,SUN STAFF

Women who have just had babies run a much higher risk of stroke than other young women, according to a new study conducted at 46 hospitals in the Baltimore-Washington area.

While it was widely believed that pregnancy increases the risk of stroke, this is the first time that researchers have been able to pin down the likelihood. What's more, they discovered that the period of greatest risk is from childbirth to six weeks after delivery.

The study looked at two of the most common types of stroke. Compared with women ages 18 to 44 who hadn't been pregnant, women in the postpartum stage run 8.7 times the risk of an ischemic stroke, in which a blood vessel becomes blocked. They also have a 28-fold risk of intracerebral hemorrhage, when a blood vessel breaks deep within the brain.

In both cases, if starved for oxygen long enough, brain tissue dies.

The study, published today in the New England Journal of Medicine, also takes the first steps toward understanding why younger people suffer strokes.

The Baltimore-Washington Cooperative Young Stroke Study, a regional-based hospital registry that includes five Central Maryland counties, is one of only a few nationwide. This is one of the first findings to emerge from the investigation.

Overall, the excess risk of stroke during pregnancy and the six weeks after delivery was found to be 8.1 strokes per 100,000 pregnancies. The study looked at all women who were discharged from the 46 hospitals in two years -- 1988 and 1991.

Despite the multiplied risk, physicians stressed that the absolute number of strokes among pregnant and postpartum women is extremely small.

"Naturally, if they have adopted healthy habits for benefit of the baby, they should continue them," said Dr. Steven J. Kittner, the study's lead author and an associate professor of neurology and epidemiology and preventive medicine at the University of Maryland School of Medicine.

Factors that might explain the higher postpartum risk are the large decrease in blood volume following delivery, and the woman's rapidly changing hormonal status.

"The whole biology of a woman is obviously completely changed during pregnancy and undergoes a lot of changes afterwards," Kittner said. "Identifying this as a period of increased risk may prompt research into why this is the case."

The postpartum period confers as much risk on a woman as some of the most common stroke factors. Diabetes, hypertension and smoking, for instance, increase the risk of stroke four to five times.

Typical symptoms

Dr. Constance Johnson, one of the study's authors, said women who have delivered their babies should be aware of the typical stroke symptoms: double vision, loss of vision in one eye, or numbness, tingling, or weakness on one side of the body. Headaches could also be a sign, she said, particularly if the woman didn't have them before delivering.

"When you're home, and you've had your baby, you may think the risk is over, but it's not. That's the time you're going to have a problem," said Johnson, an assistant professor of neurology and director of the neuro-vascular center at Johns Hopkins Hospital.

Overall, the likelihood that people ages 15 to 44 will suffer a stroke is twice as great as that they will develop multiple sclerosis, Kittner said. But many are unaware that strokes affect younger people.

Johnson said she often sees patients who ignore symptoms and don't go to the hospital, despite the fact that a drug recently approved for use in stroke can be given in emergency rooms and stem damage.

When Barbara Murphy, 35, couldn't answer a co-worker's question one day last summer, her colleague laughed and walked out, thinking she was teasing. Then Murphy couldn't spell a name she was trying to look up in her Rolodex. So the Annapolis woman left work and rested at home. It was only the next morning, still feeling strange and struggling to speak, that she went to the doctor's office.

Magnetic resonance imaging revealed she had suffered a stroke.

'I just cried'

"I just cried. I didn't know what was going on, but a stroke wasn't even anything that had crossed my mind," said Murphy, who now takes blood-thinning medicine and occasionally struggles to spell words.

Murphy's stroke was not associated with pregnancy, and its cause remains unknown.

Dr. John R. Marler, a neurologist at the National Institute of Neurological Disorders and Stroke, which is funding some of the work, said the Baltimore-Washington undertaking is significant because there are enough hospitals, and enough ethnic diversity, to apply the findings to the general population.

Stroke is the nation's third-leading killer and a major cause of disability among adults, affecting about 500,000 Americans each year. Of the more than 3 million Americans who have survived a stroke, more than 2 million deal with crippling conditions including paralysis, memory lapses and loss of speech.

Twenty years ago, physicians believed that most strokes were caused by problems in blood vessels or in the heart.

They now know that up to a third of people who have strokes don't have these problems. Researchers are on the trail of other causes, including clotting factors in the blood, that may be implicated.

Pub Date: 9/12/96

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