Coping with serum screening for Down syndrome when the results is given as a numeric value.

Forty-six pregnant women undergoing second-trimester biochemical screening for Down syndrome were asked to fill in the State-Trait Anxiety Inventory (STAI) questionnaire to assess their anxiety level at two different moments: when recruited to the study (at 11-13 weeks' gestation), and after the test result was communicated. The test result was given as a numeric value of risk (1/x), rather than as positive/negative. There were 10 women in whom the risk after biochemical screening increased (median delta risk = +1/535, range = 1/69 to 1/1083), whereas in the remainder the risk decreased (median delta risk = -1/1576; range = -1/142 to -1/4947) compared with the baseline value calculated on maternal age alone. Although only in a minority of women the STAI score after biochemical screening exceeded the reference range, the change in the STAI score was significantly higher when the risk increased, and the change in the risk estimate correlated significantly with the change in this index of anxiety. Three out of seven women with a 'negative' test, but increased risk estimate and increased anxiety after biochemical screening chose to undergo amniocentesis. A policy of providing the result of biochemical screening for Down syndrome as a numeric value, even for 'negative' tests, may cause some women to experience anxiety and request amniocentesis.