Moderately increased risks of Down's syndrome (1/51-1/270) identified on first trimester sequential screening: what do patients do with this information?

ABSTRACT

OBJECTIVE: To document patient decisions after being informed of a first trimester sequential screen Down's syndrome risk between 1/51 and 1/270. SETTING: A database analysis of sequential screen results for patients seen in the Philadelphia, PA (USA) area between January 2006 and March 2008 was examined. METHODS: All patients with first trimester sequential screen Down's syndrome risks in the 1/51-1/270 range were identified. Patient decisions regarding invasive testing (prior to completing the second trimester stage of the sequential screen), completion of the second trimester blood draw or no additional testing were tabulated. RESULTS: A total of 10,850 patients underwent first trimester sequential screening during this interval. Five hundred and fifty-seven patients (5.1%) met the study inclusion criteria and had risks between 1/51 and 1/270. Ninety-three percent of these patients completed the sequential screening process before making any decisions regarding invasive testing. Four percent did not elect an invasive prenatal diagnosis procedure, but also did not complete the second trimester sequential screening blood draw and only 3.2% elected an invasive procedure based on their first trimester risk without completing the second trimester blood draw. Five women (0.9%) with low risks after the second stage screen chose to have an amniocentesis. CONCLUSION: The vast majority (97%) of patients in the moderately increased Down's syndrome risk range (1/51-1/270) following first trimester sequential screening did not pursue an invasive procedure based on their first trimester sequential screen risk. Using a > or = 1/50 risk cut-off in the first trimester is an effective screening policy for sequential screening.