In the United States, more than 220,000 adults under the age of 45 have had a stroke. Secondary stroke prevention is critical in this population because of the potential impact of a second stroke on productivity and future quality of life. In addition to conventional stroke risk factors, younger patients have special risk factors inherent to genetic and environmental elements, such as the use of illicit drugs and cardiac abnormalities; in women, risk factors include pregnancy, migraine, and the use of oral contraceptives.