especially in young women.
There are several clotting disorders known collectively as thrombophilias. These are much more common than is usually realized. Here is a newsletter from an organization that is trying to help the public be more aware of this problem.
While both men and women can have the genetic predisposition, the problems can be much more severe for women because of the influence of the hormone estrogen. I have been astounded to hear, quite casually, from a number of young women who had abnormal blood clots related to the use of the birth control pill. This can also be a problem in pregnancy, but the pill seems to be a much bigger contributor. Recent news reports about the patch (Ortho Evra) have brought this to the public eye again, but the reality is that the estrogen containing hormonal contraceptives have ALWAYS had a known connection with strokes, heart attacks, and other thrombotic events.
If you can't read the whole newsletter, at least go to page 4. And then pray for all those involved in this story.