July 28, 2011 -- Strokes during pregnancy and after childbirth have increased at what one CDC researcher calls an alarming rate.
Elena V. Kuklina, MD, PhD, a CDC epidemiologist, and colleagues compared stroke rates during pregnancy, during childbirth, and after childbirth. They used a national database that included discharge information from 1,000 hospitals.
The researchers compared the pregnancy-related stroke rates in the years 1994-1995 and 2006-2007.
"What we found was there was approximately a 50% increase in all stroke," she says. Pregnancy-related strokes totaled about 4,000 in 1994-1995, or about 2,000 each year. In 2006-2007, they totaled about 6,000, or 3,000 annually.
The number of deliveries in the two periods was comparable, she says.
Kuklina also looked separately at the three different time periods: during pregnancy, during childbirth, and immediately after childbirth. Compared to the earlier years, she found a 47% increase in stroke during pregnancy and an 83% increase after childbirth. The rate during delivery did not change.
Younger pregnant women -- those 25 to 34 -- were most likely to be hospitalized for stroke, she found.
''We have a population of pregnant women who have a higher risk of having stroke now compared to 10 years ago," she tells WebMD.
Each year in the U.S., about 795,000 people suffer a new or recurrent stroke, according to the American Heart Association.
The researchers looked at all types of strokes, including those caused by clots and by reduced blood flow. They also looked at so-called mini-strokes or transient ischemic attacks (TIAs), which are considered a warning sign of stroke.
More women hospitalized for stroke had high blood pressure in 2006-2007 than in the first period studied. For instance, nearly 41% of those who had a stroke after delivery had high blood pressure. Having high blood pressure increased the risk of pregnancy-related stroke up to about six times, Kuklina says. Having heart disease boosted the risk of stroke by as much as about 10 times.