ADN Fœtal Circulant, Grossesse et Pathologies Malignes

In France in 2021, 90% of pregnant women chose to undergo screening for Trisomy 21, and 128,958 women benefited from a fetal aneuploidy screening test based on the analysis of cell-free DNA (cfDNA) in maternal blood. At the beginning of its use, this analysis was limited to screening for Trisomy 21, but it now allows the study of all chromosomes (expanded screening). More than half of fetal chromosomal abnormality screenings are expanded tests, and this practice continues to grow. In oncology, circulating tumor DNA (ctDNA) is studied for the detection, prognostic evaluation, and monitoring of the effectiveness of certain treatments. The high-throughput sequencing tools used for aneuploidy screening during pregnancy are likely to detect malignant diseases. Cancer is associated with pregnancy in 1 in 1,000 to 1 in 1,500 pregnant women, and the spread of expanded aneuploidy screening during pregnancy makes it possible to detect maternal cancers, including at infraclinical stages. This study will therefore help manage situations involving difficult-to-interpret results, such as suspected maternal cancer. It will make it possible to identify specific chromosomal abnormalities to be tested, which could potentially be included in future recommendations. In a second stage, it could contribute to harmonizing the practices of laboratory specialists performing fetal chromosomal abnormality screening using cfDNA.