We assessed the perception of teratogenic risk by 80 women attending an antenatal consultation service for drug, chemical, and radiation exposure. Women exposed to agents not known to be teratogenic assigned themselves a risk of 24% +/- 2.8% for major malformation before the relevant medical literature was delivered to them and 14.5% +/- 3% thereafter. These women accurately estimated the risk for major malformation in the general population (5.6% +/- 1.3%). The tendency to terminate pregnancy when exposed to a nonteratogen significantly decreased after the consultation. Eleven patients exposed to drugs known to be teratogenic assigned a risk of 36.2% +/- 11.7% before the interview and did not change their perception thereafter (36.7% +/- 15.8%). Similarly, their tendency to continue or terminate pregnancy did not change; three of them eventually chose to terminate the pregnancy. Advising women about their teratogenic risk early in pregnancy may prevent unjustified termination of many pregnancies and may help to inform women exposed to proven teratogens about the known risk.