Non-invasive prenatal screening for fetal aneuploidy in twin pregnancies by cell-free DNA analysis

Objective: To evaluate the efficacy of Cell-free DNA (cfDNA) based non-invasive prenatal testing (NIPS) in detecting fetal chromosomal aneuploidies among twin pregnancies. Materials and Methods: A cohort of 384 women with twin pregnancies were recruited for chromosomal aneuploidies testing through NIPS. cfDNA was extracted from maternal blood serum and sequenced by massively parallel sequencing (MPS). Result: Two cases of trisomy 21 (T21), one case of trisomy 13 (T13), and two cases of sex chromosomal aneuploidies (SCA) in twin pregnancies were correctly identified through MPS and confirmed their discordant fetal kaiyotypes (one normal and the other trisomy) by karyotyping; 378 twin pregnancies cases with negative NIPS results were confirmed through postnatal phone follow-up. NIPS detection rate and positive predictive value for T21, T13, and SCA were 100%, respectively, in twin pregnancies; sensitivity and specificity towards T21 and T13 in twin pregnancies were both 100%. Conclusion: cfDNA based NIPS for fetal chromosomal aneuploidy have shown a satisfactory clinical performance in twin pregnancies.