Performance and Diagnostic Value of Genome-Wide Noninvasive Prenatal Testing in Multiple Gestations.

van Riel, Margot Brison, Nathalie Baetens, Machteld Blaumeiser, Bettina Boemer, François Bourlard, Laura Bulk, Saskia De Leener, Anne [UCL] Désir, Julie Devriendt, Koenraad Dheedene, Annelies Duquenne, Armelle [UCL] Fieremans, Nathalie Fieuw, Annelies Gatot, Jean-Stéphane Grisart, Bernard Janssens, Sandra Khudashvili, Naïri Lannoo, Lore Marichal, Axel Meunier, Colombine Palmeira, Leonor Parijs, Ilse Pichon, Bruno Roets, Ellen Sammels, Eva Smits, Guillaume Suenaert, Marion Sznajer, Yves [UCL] Van den Bogaert, Kris Vancoillie, Leen Vandeputte, Lotte Vantroys, Elise Vermeesch, Joris Robert Janssens, Katrien et al.[show all]

(eng) OBJECTIVE: To evaluate the accuracy and diagnostic value of genome-wide noninvasive prenatal testing (NIPT) for the detection of fetal aneuploidies in multiple gestations, with a focus on dichorionic-diamniotic twin pregnancies. METHODS: We performed a retrospective cohort study including data from pregnant women with a twin or higher-order gestation who underwent genome-wide NIPT at one of the eight Belgian genetic centers between November 1, 2013, and March 1, 2020. Chorionicity and amnionicity were determined by ultrasonography. Follow-up invasive testing was carried out in the event of positive NIPT results. Sensitivity and specificity were calculated for the detection of trisomy 21, 18, and 13 in the dichorionic-diamniotic twin cohort. RESULTS: Unique NIPT analyses were performed for 4,150 pregnant women with a multiple gestation and an additional 767 with vanishing gestations. The failure rate in multiple gestations excluding vanishing gestations ranged from 0% to 11.7% among the different genetic centers. Overall, the failure rate was 4.8%, which could be reduced to 1.2% after single resampling. There were no common fetal trisomies detected among the 86 monochorionic-monoamniotic and 25 triplet cases. Two monochorionic-diamniotic twins had an NIPT result indicative of a trisomy 21, which was confirmed in both fetuses. Among 2,716 dichorionic-diamniotic twin gestations, a sensitivity of 100% (95% CI 74.12-100%) and a specificity of 100% (95% CI 99.86-100%) was reached for trisomy 21 (n=12). For trisomy 18 (n=3), the respective values were 75% (95% CI 30.06-95.44%) sensitivity and 100% (95% CI 99.86-100%) specificity, and for trisomy 13 (n=2), 100% (95% CI 20.65-100%) sensitivity and 99.96% (95% CI 99.79-99.99%) specificity. In the vanishing gestation group, 28 NIPT results were positive for trisomy 21, 18, or 13, with only five confirmed trisomies. CONCLUSION: Genome-wide NIPT performed accurately for detection of aneuploidy in dichorionic-diamniotic twin gestations.