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Master Thesis

Analyse de l'ADN foetal dans le sang maternel comme test de dépistage pour la trisomie 21 chez les grossesses gémellaires

Abstract : Objectives: to evaluate the performance of noninvasive prenatal testing by cell-free circulating fetal DNA in maternal blood (cfDNA) in screening for trisomies 21 in twin pregnancies. Methods: cfDNA was performed in 492 patients with twin pregnancies without ultrasound anomalies in the first trimester as a first-line screening test or after serum screening. Data were collected prospectively and a retrospective analysis was done. CfDNA was executed by massive parallel technique. The fetal fraction threshold for test evaluation was 8%. Regression analysis was performed to evaluate the effect of different parameters on the test failure rate. Performance of the test was also considered. Results: in 377 patients, the test was prescribed first line and in 115 after standard serum screening. 12 tests (2.9%) have initially failed on the 420 pregnancies with available outcomes and regression analysis found only maternal weight as a significant independent factor of test failure. A second test was performed on 10 patients, all of them had an available result. cfDNA identified all 3 cases of trisomy 21. The sensitivity was 100.0% (95% CI [29.2% - 100.0%]) and specificity was 99.8% (95% CI [98.7% - 100.0%]). There was no significant difference between spontaneous pregnancies and those induced by assisted reproductive technologies (ART), in terms of fetal fraction percentage, no-call results for cfDNA screening, maternal weight or test performance between the two groups. Conclusion: in twin pregnancies, the performance and success rate of the cfDNA are excellent. Therefore, cfDNA could be offered in routine practice as a first-line screening test in this population.
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Master Thesis
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Grégoire Le Conte. Analyse de l'ADN foetal dans le sang maternel comme test de dépistage pour la trisomie 21 chez les grossesses gémellaires. Médecine humaine et pathologie. 2018. ⟨dumas-02292929⟩



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