A program to reduce pregnancies in women who use isotretinoin, a known teratogen, for severe, cystic acne is being considered as a model for thalidomide. In 1988, “an unprecedented and novel” pregnancy prevention program was developed for isotretinoin users, according to Allen A. Mitchell, MD, professor of epidemiology and pediatrics at the Boston University School of Public Health. Rates of oral contraceptive use and abstinence were higher in the isotretinoin users than in the general public. The pregnancy rate was 7% that of the U.S. population. Of the 210 009 women with complete follow-up, 623 became pregnant. Two thirds of the pregnancies resulted from contraceptive failure; 68% were electively aborted, 16% were spontaneously aborted, 3% were ectopic, and 11% resulted in live births. As expected, 25% to 30% of the babies had birth defects. Mitchell, who implemented the isotretinoin registry, has suggested that a more stringent program may be required for thalidomide users.