thalidomide syndrome

thalidomide syndrome A congenital malformation syndrome that is caused by maternal exposure to thalidomide. Although thalidomide syndrome is epitomized by the flipper-like limbs (phocomelia), thalidomide causes a wide range of birth defects, including absence of ears with deafness; defects of the muscles of the eye and of the face; absence or hypoplasia (underdevelopment) of the arms, especially affecting the radius and the thumb; thumbs with three joints; defects of the femur and of the tibia; and malformations of the heart, bowel, uterus, and gallbladder. The pattern of malformations depends on the time of intake of the drug. Thalidomide usually causes no malformations if taken before the 34th day or after the 50th day after the last menstruation. During the sensitive period, taking thalidomide causes the following sequence of malformations: 35th–37th day: absent ears and deafness; 39th–41st day: absent arms; 43rd–44th day: phocomelia with threefingers; 46th–48th day: thumbs with three joints. If thalidomide is taken throughout the sensitive period, the baby may have severe defects of the ears, arms, legs, and internal organs, and the baby may die. About 40 percent of thalidomide babies died before their first birthday, but many thalidomide babies have lived into adulthood.