Significance of noninvasive prenatal testing using massively parallel sequencing in women with twin or vanishing twin pregnancies.

Noninvasive prenatal testing diagnoses fetal aneuploidies in singleton pregnancies with trisomy 21, 18, or 13 accurately. However, clinical data on noninvasive prenatal testing in women with twin or vanishing twin pregnancies are limited. We report on the accuracy and prenatal and neonatal outcomes of noninvasive prenatal testing in twin and vanishing twin pregnancies. This retrospective study was conducted at 22 facilities belonging to the Noninvasive Prenatal Testing Consortium, part of a nationwide project in Japan, visited by women with twin or vanishing twin pregnancies between January 2015 and March 2022. This study investigated the accuracy and perinatal and neonatal outcomes of noninvasive prenatal testing using massively parallel sequencing in twin or vanishing twin pregnancies. Of 1013 women with twin pregnancies, 986 (97.3%) had negative; 13 (1.3%), positive; and 14 (1.4%), non-reportable noninvasive prenatal testing results. Of 225 women with vanishing twins, 203 (90.2%) had negative; 11 (4.9%), positive; and 11 (4.9%), non-reportable results. Among 1693 fetuses (77.3%) excluding 497 unknowns were available for follow-up, 1476 were from twin pregnancies, and 134 were from vanishing twin pregnancies, totaling 1610 babies has born. No false negatives were observed in the cases followed. These results indicate that noninvasive prenatal testing is useful for vanishing twin pregnancies and provide reassurance for pregnant women with twins and vanishing twins.