There is an increased risk of blood clots, or venous thromboembolism, associated with the use of Sprintec and other oral contraceptives. This risk is directly related to the amount of estrogen in the pills. Sprintec does have a lower estrogen dose compared to some other combined oral contraceptives. However, there is an increased risk for blood clots with any combined oral contraceptive. The risk is relatively low; pregnancy is approximately twice as likely to cause blood clots compared to using oral contraceptives. The risk for blood clots is higher in older women, over age 35 years, and in women who smoke.