Hi, aspirin is considered to be in pregnancy category D by the FDA if full dose aspirin is taken in the third trimester. Use of nonsteroidal anti-inflammatory drugs during the third trimester of pregnancy should be avoided due to effects on the fetal cardiovascular system (closure of the ductus arteriosus). Aspirin use in pregnancy has been associated with alterations in both maternal and fetal hemostasis. In addition, high doses have been associated with increased perinatal mortality, intrauterine growth retardation, and teratogenic effects. During the first two trimesters of pregnancy, aspirin should only be given during pregnancy when clearly needed and when benefit outweighs risk. Increased maternal bleeding can occur during delivery when aspirin is used 1 week prior to and/or during labor and delivery. Prolonged gestation and labor have been reported due to aspirin's inhibition of prostaglandin...