Fetal warfarin syndrome, also known as fetal anticoagulant syndrome, DiSala syndrome, fetal coumarin syndrome, or warfarin embryopathy, is the result of teratogenic effects of the anticoagulant warfarin when taken by women during pregnancy (National Library of Medicine. Warfarin is a coumarin derivative that is used to treat clotting disorders such as phlebitis and as an anticoagulant rodenticide (International Programme on Chemical Safety. The most prescribed oral anticoagulant, it is the 11th-most prescribed drug in the United States.