Objective: To assess the value of non-invasive prenatal testing (NIPT) for the detection of fetal chromosomal aneuploidies in women with twin pregnancy.
Methods: A total of 2473 women with twin pregnancy underwent the NIPT test to assess the risk for fetal chromosomal aneuploidies from January 2016 to September 2019. Those with a high risk by NIPT were confirmed by amniocentesis or chorionic villus sampling. All cases were followed up to evaluate the positive prediction value of NIPT for twin pregnancies.
Results: Among the 2473 women, the NIPT test has identified 31 cases (1.25%) with a high risk for fetal chromosomal aneuploidies, which included 5 cases of trisomy 21, 1 case of chromosome 21 deletion, 4 cases of trisomy 18, 7 cases of sex chromosome abnormality and 14 cases of microdeletion and microduplication. By invasive prenatal diagnosis or chromosomal karyotyping analysis of neonates, 5 cases of trisomy 21, 3 cases of trisomy 18, 1 case of sex chromosome abnormality, and 2 cases of microdeletion and microduplication were confirmed, which yielded a positive predictive value of 100%, 75%, 25% and 25%, respectively.
Conclusion: NIPT can be used for the screening of fetal chromosomal aneuploidies in women with twin pregnancy with high accuracy. The method is non-invasive, safe and effective for the screening of fetal chromosomal aneuploidies, in particular trisomy 21.