How unexpected are unexpected findings in prenatal cytogenetic diagnosis? A literature review.

The objective of this review was to gain understanding about unexpected findings in prenatal cytogenetic diagnosis. This category of results might be excluded from prenatal testing when new molecular tests such as I-FISH and QF-PCR will be applied in a future scenario of targeted testing. The literature was systematically searched for publications wherein the term unexpected or a synonym refers to testing results with specific problems. On the selected articles a qualitative analysis was performed, using the methods of cross-case analysis and within-case analysis. Sixteen articles published between 1979 and 2003 were selected. Analysis led to the classification of four problems of unexpected findings: I. unexpected for professionals; II. unexpected for patients; III. uncertainty; IV. other difficult counselling issues. We conclude that currently the problems of unexpected findings relate only slightly to their unexpected character. Instead, the main problems of unexpected findings relate to uncertainty and other aspects which create difficult counselling issues. As such, unexpected findings can be distinguished only gradually from standard results. Before targeted testing can be applied it is necessary to establish exact criteria in order to discern unexpected findings from standard testing results.