Credit: Nina Matthews
SAN DIEGO—A woman’s risk of thrombosis remains significantly elevated for 12 weeks after delivering a baby, according to research presented at the International Stroke Conference 2014.
The study suggested that pregnant and postpartum women have a low absolute risk of experiencing thrombotic events.
However, their risk is nearly 11 times higher than normal for the first 6 weeks after delivery. And they have roughly twice the normal risk of thrombosis in the following 6 weeks.
Hooman Kamel, MD, of Weill Cornell Medical College in New York, presented these findings at the meeting as abstract 216.*
Dr Kamel and his colleagues had analyzed data on 1,687,930 women who were admitted for labor and delivery at California hospitals from 2005 through 2010.
The researchers compared the risk of thrombosis during sequential 6-week periods after delivery to the same 6-week period 1 year later (0-6 weeks, 7-12 weeks, 13-18 weeks, and 19-24 weeks).
In all, 1015 women had a thrombotic event after delivery, including 720 cases of venous thromboembolism, 248 strokes, and 47 cases of myocardial infarction.
In the first 6 weeks after delivery, a woman’s risk of thrombosis was 10.8 times higher than normal. There were 24.4 thrombotic events per 100,000 deliveries in the first 6 weeks after delivery, compared to 2.3 events during the same period 1 year later.
From week 7 to 12 after delivery, the risk of thrombosis was 2.2 times higher than normal. There were 5.6 thrombotic events per 100,000 deliveries in the 7 to 12 weeks after delivery, compared to 2.6 events during the same period 1 year later.
The risk of thrombosis was 1.4 times higher than normal from 13 to 18 weeks after delivery, although this was not a significant increase. And by weeks 19 through 24, the risk of thrombosis had returned to normal.
“While rare, blood clots are a serious cause of disability and death in pregnant and postpartum women . . . ,” Dr Kamel said. “Clinicians should consider our results when caring for high-risk postpartum patients, such as those with previous clots, or postpartum patients with symptoms concerning for thrombosis.”
*Information in the abstract differs from that presented at the meeting.