tokens: Aspirin ( acetylsalicylic acid [ ASA ] ) , an irreversible cyclooxygenase 1 and 2 inhibitor , induces developmental anomalies when administered to Wistar rats on gestational day ( GD ) 9 , 10 , or 11 ( Kimmel CA , Wilson JG , Schumacher HJ . Teratology 4 : 15 - 24 , 1971 ) .