Assessment of risk by pregnant women: Implications for genetic counseling and education

Abstract One of the central elements of genetic counseling is the transmission of quantitative information concerning risk of defects in an unborn child from counselor to client. In order to investigate this subject, we studied the understanding of numeric and nonnumeric descriptions of genetic risk by 190 pregnant women. Specifically, three risk issues were explored: (1) whether women were able to interpret numeric risks as percentages; (2) whether shifting denominators affected risk assessment; and (3) the comparative assessment of the risk of birth defects, in general, and the risk of a neural tube defect, in particular. Respondents were much less likely to assign the correct percentage equivalent to numeric risk information when the denominator was 1,000 rather than 100. The ability to correctly identify percentage equivalents affected respondents’ quantitative assessment of the frequency of neural tube defects. Shifting the denominator from 100 to 1,000, however, did not affect women's quantitative assessment of the rarity of birth defects. In general, the respondents preserved the relative risk of birth defects and neural tube defects in their choice of descriptive terms. The majority of women evaluated serious birth defects as occurring “often” or “occasionally” and NTDS as occurring “rarely” or “very rarely.”