A consecutive cohort of 71 women eligible for amniocentesis because they were over 38 years of age completed questionnaires during the first trimester of pregnancy. Sixty-one women underwent amniocentesis, an uptake rate of 86%. Uptake was associated with a less negative attitude towards termination of an affected baby and a higher perceived risk of the fetus being abnormal. It was not associated with actual age-related risks. There was no significant relation between actual risk and perceived risk. The results of this study suggests that it is important for doctors to understand the basis of women's decisions to have amniocentesis, and the difference between actual and perceived risk if they are to communicate effectively with women about the test and their options.