Warning symbols are used on teratogenic medications to communicate the message that women should (1) not take that medication if they may already be pregnant, and (2) not get pregnant while taking that medication. Communications research indicates that people interpret symbols or pictures in different ways. Other studies have shown that patients do not always receive education materials that are part of prescription protocol. Researchers at the Centers for Disease Control and Prevention (CDC) tested the interpretation of the teratogen warning symbol and its ability to convey the correct information without accompanying education.


A teratogen warning symbol currently printed on some medication packaging uses graphics and text warning the user not to get pregnant. Researchers interviewed women of childbearing age about their interpretation of the warning symbol and its meaning. Ninety-seven women were interviewed in a variety of locations, including public health clinics, literacy and job training offices, health clubs, and malls.


Only 21% of women interpreted correctly without prompting that they should either not take the medication if they are pregnant or not get pregnant while taking the medication. Twenty-seven percent of women first thought the symbol meant the package contained birth control medication, and 24% said it simply indicated the package contained drugs or medicine. An additional 7% said they did not know what the symbol was supposed to mean; 39% of respondents offered circumstances in which prescription medications might be shared.


Misinterpretation of warning symbols can result in serious consequences. This research should serve as an urgent call for mandating education for all patients receiving drugs with teratogenic properties, and careful pretesting and modification of warning symbols before they are used on medications with teratogenic effects. Teratology 64:148–153, 2001. Published 2001 Wiley-Liss, Inc.