Aspirin has been assigned to pregnancy category D by the FDA. Pravastatin has been assigned to pregnancy category X by the FDA. The frequency of fetal exposure to aspirin reported in many studies may be underestimated because aspirin (and other salicylates) occur in many over-the-counter preparations and women may fail to recall taking aspirin and over-the-counter drugs. NSAID use 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. Aspirin should only be given during pregnancy 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. Animal studies using pravastatin failed to reveal evidence of teratogenicity, however, studies with other HMG-CoA reductase inhibitors revealed an increased incidence of skeletal malformations. HMG-CoA reductase inhibitors are known to inhibit biosynthetic processes necessary for fetal development. There are no controlled data in human pregnancy. Pravastatin use is considered contraindicated during pregnancy.

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