Diagnosis Accuracy of Noninvasive Screening by PCR Digital for Down Syndrom

The main objective of this study is to estimate the intrinsic diagnostic qualities of the digital dPCR in the screening of T21 from a multicentrique sample of patients with pregnancies at high risk of T21 (risk \> 1/250). The profit expected from this technique is to propose to the encircled women a screening more successful than that of the screening combined(organized) of the 1st quarter, simple of realization and in a moderate cost. We thus propose here an original alternative(alternate) method to the exclusive, expensive and binding techniques of top-debit(-flow). The recent technical improvements and his(her,its) advantages medical - economic allow to envisage a reliable, strong and long-lasting use of the dPCR in clinical routine in the DPNI of T21 in most of the laboratories. This pilot project could serve for the later development of a study of clinical validation multicentrique of large scale(big turntable ladder).