The dangers of thrombosis High risk of thrombosis in everyday life All of this is no reason to panic: We deliberately take on much higher thrombosis risks elsewhere than they might now — perhaps — come by the way of vaccination. In a well-known and scientifically proved example, for every million women who take the birth control pill, about 1,100 will get thrombosis. In addition, various circumstances or behaviors have been shown to double our risk of thrombosis. These include: obesity, travel (especially long-distance flights, car, bus or train rides) and smoking. All of these fa...