- The abstract is interesting, it's telling us that, clearly, smoking and oral contraceptives increase the risk of stroke in young women, which we knew, the added information is really about the blood group, and that is something, that a lot of neurologists, non-hematologists, probably don't think about, so, and it is information that a lot of people have. If you ever donated blood, you know what your blood type is. And in looking up information related to this topic, and I always thinking about why blood group might be increasing the risk of stroke in young women, in addition to smoking and oral contraceptives, I started thinking about the von Willebrand factor, and how this is related to blood group, and how it interacts with platelets, and thinking that, maybe the connection here, with blood group, is the von Willebrand factor increasing the risk of platelets clumping, and therefore leading to a stroke.