WASHINGTON – Women of all ages should pay more attention to the risk of stroke than the average man, watching their blood pressure carefully even before they think about taking birth control pills or getting pregnant, according to a new set of guidelines released Thursday.

Women are also more likely to have risk factors associated with stroke, such as migraines, depression, diabetes and abnormal heart rhythm known as atrial fibrillation. The new guidelines from the American Heart Association were the first such recommendations to prevent strokes in women. Stroke is the fourth-leading cause of death for all Americans but the third-leading cause of death for women, after heart disease and cancer.

Women share many of the same risk factors as men for stroke, but they also have unique risks that come with pregnancy complications and hormone use, said Cheryl Bushnell, associate professor of neurology at Wake Forest Baptist Medical Center in Winston-Salem, N.C., who led a group of experts that developed the guidelines.

Previous guidelines about cardiovascular prevention in women have included some information about stroke. "But it was buried in there," said Bushnell, who has been studying the topic for more than a decade. "We wanted to take topics that are really women-specific and emphasize stroke and put it all in one guideline."

The recommendations, published in the journal Stroke, emphasize the importance of controlling blood pressure, especially in young women. They are aimed at a broader age range than most recommendations.

"We're talking about being aware of blood pressure before you ever take birth control medication, being aware of blood pressure before you even get pregnant," Bushnell said.

Symptoms can be subtle

A stroke occurs when the blood supply to the brain is blocked or when a blood vessel in the brain ruptures, causing brain tissue to die.

The signs of stroke in women are similar to those in men, including face drooping, sudden numbness or weakness of the arm, and difficulty with speech or trouble understanding. But symptoms in women may be more vague or subtle, Bushnell said. Women are more likely to have a change in their consciousness or their ability to communicate with people, she said.

"There was nothing to indicate I was going to have a stroke," said Denise Miller, who suffered a stroke last year that fooled doctors at two northeast Ohio hospitals before it was finally diagnosed at the Cleveland Clinic. She was 36 and had no traditional risk factors. But she had frequent migraines with aura — dizziness or altered senses such as tingling, ringing ears or sensitivity to light, she said.

These headaches are more common in women and the new guidelines issued Thursday flag them as a concern. Miller recovered but has some lingering numbness and vision problems.

'More adversely affected'

An estimated 6.8 million people in the United States are living after having had a stroke, including 3.8 million women, according to statistics from the American Heart Association. Each year, more than half of the estimated 800,000 people who have a stroke each year are women.

As women increasingly outlive men, their lifetime risk of stroke becomes higher. Women are also more likely to be living alone and widowed after suffering a stroke, and are more likely to be institutionalized, research shows.

"As the baby boomer generation ages, more people are at risk for stroke, and women in particular as they enter their 50s, 60s and 70s," said Alex Dromerick, a neurology professor at Georgetown University.

"Women are more adversely affected by stroke than men," the guidelines said. "Now more than ever, it is critical to identify women at higher risk for stroke and initiate the appropriate prevention strategies."

Researchers said that pregnancy-induced high blood pressure, called pre-eclampsia, should be considered a risk factor for stroke later in life. That's because women who have pre-eclampsia have double the risk of stroke and four times the risk of high blood pressure when they're older, researchers said. Doctors should treat other stroke risk factors like smoking, obesity and high cholesterol in these women early.

One measure that could be controversial is its recommendation to treat pregnant women with moderately high blood pressure (150 to 159 mmHg/100 to 109 mmHg) with blood pressure medication. That goes against recommendations by the American College of Obstetricians and Gynecologists, Bushnell said.

"We are going out on a limb," Bushnell said.

The paper also suggests that doctors monitor women age 75 for the most common type of irregular heartbeats, which is associated with a fourfold to fivefold increased risk of stroke. It also recommends that women exercise regularly, abstain from smoking, and eat a diet full of fruits, vegetables, grains, nuts, olive oil and foods low in saturated fats to help prevent stroke.

"Prevention can start at a young age," Bushnell said. "If younger women get started with prevention now, they can perhaps prevent themselves from having a stroke later in life."

The Associated Press and Bloomberg News contributed to this report.