Lead author Dr Elena V Kuklina, senior service fellow and epidemiologist at the CDC's Division for Heart Disease and Stroke Prevention in Atlanta, Georgia, told the media she was surprised at the "substantial" increase:
"Our results indicate an urgent need to take a closer look. Stroke is such a debilitating condition. We need to put more effort into prevention," she urged.
Kuklina and colleagues report that the overall rate of women having strokes while they are expecting a baby and in the three months after birth went up 54% in the 12 years leading up to 2006-07. They suggest the main reason is because of high blood pressure and obesity.
For their study, they used data on 5 to 8 million discharge records from 1,000 hospitals covering the period 1994-95 to 2006-07. From these they could see how the rate of strokes had changed in women who attended hospital during pregnancy, during delivery, and recently after giving birth.
They found that:
- Pregnancy-related stroke hospitalizations went up by 54%, from 4,085 to 6,293 over the 12 years leading up to 2006- 07.
- Strokes in pregnancy went up by 47% (from 0.15 to 0.22 per 1,000 deliveries).
- Strokes recently after giving birth went up by 83% (from 0.12 to 0.22 per 1,000 deliveries).
- Strokes during delivery did not change (they stayed at 0.27 per 1,000 deliveries).
- In 2006-07, about 32% and 53% of women who were hospitalized after having strokes in pregnancy and shortly after giving birth respectively had either high blood pressure or heart disease.
- Increased prevalence of these two conditions over the 12 years up to 2006-07 accounted for almost all the increase in stroke hospitalization after giving birth that occurred in the same period.
"Since pregnancy by itself is a risk factor, if you have one of these other stroke risk factors, it doubles the risk," so it is best to enter pregnancy with good cardiovascular health, without additional risk factors, said Kuklina.
We need to give doctors and patients better guidelines for monitoring and caring for women before, during and after childbirth, she added.
There is also a need to do more research on pregnant women specifically, said Kuklina, who said they could only find 11 cases of stroke related to pregnancy when she and her colleagues searched the literature to review the field.
Another problem is that because of the risk of harming the fetus, pregnant women are rarely included in clinical trials, so we know little about which drugs can safely be prescribed to women with an increased risk of stroke.
The study was funded by the CDC.
"Trends in Pregnancy Hospitalizations That Included a Stroke in the United States From 1994 to 2007: Reasons for Concern?"
Elena V. Kuklina, Xin Tong, Pooja Bansil, Mary G. George, and William M. Callaghan.
Stroke, published online before print 28 July 2011, doi:10.1161/STROKEAHA.110.610592
Link to Abstract.
Additional source: AHA.