DEAR DOCTOR K: Do women need to take special precautions to prevent a stroke?
DEAR READER: Yes, they do -- and a new set of guidelines published earlier this year helps us to understand what those steps should be. The guidelines discuss stroke risk factors that women should consider from adolescence to old age.
The first thing that may be surprising about the guidelines is that they include stroke prevention advice for young women. Most strokes occur in older people (women and men). They are unusual in middle-aged and young adults, and even more unusual in childhood. But they do occur, and some young adults are at increased risk for a stroke.
Take, for example, young women who are thinking about going on the birth control pill. Oral contraceptives boost the risk of stroke, even in younger women. The risk is greater in oral contraceptives with higher doses of estrogen, but these are prescribed less frequently today than in the past.
The risk of oral contraceptives causing a stroke starts to increase when women reach age 35. How big is the risk? In women with no other factors that also increase the risk of having a stroke (such as high blood pressure or smoking), taking a low-dose estrogen contraceptive about doubles the risk.
However, the risk is still small: about 1 out of 10,000 women on oral contraceptives will have a stroke caused by the pills each year.
In women over age 35 who also smoke, the risk of stroke increases considerably. I advise such women to avoid using estrogen-containing pills, patches or devices. I urge that more strongly when the woman has other risk factors for stroke. Indeed, the new guidelines recommend that women have their blood pressure checked before taking oral contraceptives. And they suggest that women reduce other risk factors while taking oral contraceptives.
The guidelines note that about one in 12 women develop pre-eclampsia or other blood pressure problems during pregnancy. Untreated pre-eclampsia can lead to strokes. The guidelines recommend that women who have had pre-eclampsia, or are at risk for developing it, take low-dose aspirin until delivery.
Pre-eclampsia disappears after delivery. But women who develop it are more likely to develop high blood pressure later in life, which then puts them at risk for stroke if not properly diagnosed and treated.
The guidelines also state that women who have migraines with aura have an increased risk of stroke. Women with this condition should stop smoking and consider taking medications to prevent migraines.
Atrial fibrillation is a fast and irregular heartbeat. It is also a leading cause of stroke, more so in women than in men. Women with this condition should take a blood-thinning drug to help prevent stroke.
The guidelines also recommend that women aged 65 to 79 talk with their doctor about taking a daily baby aspirin to reduce the risk of stroke.
So even though strokes can occur in women of all ages, we now know how to reduce the risks.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.