Abstract

The recent unplanned clinical demonstration of severe congenital defects in thousands of infants from the use by pregnant women of thalidomide (Medical Letter, Brit. Ed. 1962, 1, 23), with subsequent confirmation of the teratogenic effects in laboratory animals, dramatizes the need for extreme caution in administering to pregnant women any drug which may be potentially harmful to the foetus. The thalidomide experience has also established the need for the testing of all new drugs in many species of pregnant animals before use in man. Many older drugs, particularly those likely to be taken during pregnancy, should also be tested- a drug having relatively mild and infrequent injurious effects on the foetus might be used for years without any realization of the connection between the drug and the injurious effects.