First-trimester prenatal screening for Down syndrome and other aneuploidies

There has been a rapid succession of scientific and technological advances in the area of prenatal screening for Down syndrome and other chromosome abnormalities, and this has led to practice changes in Québec. AETMIS consequently deemed it necessary to examine the efficacy and the effectiveness of first-trimester prenatal screening. This assessment report looks at the efficacy and the effectiveness of first-trimester serum marker and ultrasound screening and at the different issues relating to the implementation of such screening in Québec.

AETMIS feels that, although the efficacy of first-trimester prenatal screening is satisfactory, its effectiveness has yet to be demonstrated, as indicated by numerous published studies that have examined this aspect. Studies comparing the efficacy of first-trimester screening with that of secondtrimester screening are currently under way. If the two prove to be of equal efficacy, pregnant women would nonetheless prefer first-trimester screening, since it permits an earlier diagnosis. In this report, we will also stress the importance of the information to be given to women so that they can make informed decisions.

In conclusion, given the available data, AETMIS does not recommend implementing wide-scale first-trimester prenatal screening in Québec. However, it does feel that the effectiveness, costs and implementation modalities should be assessed or determined by means of research projects in settings where quality service can be provided.