Non-invasive prenatal test to screen common trisomies in twin pregnancies

Mahtab Motevasselian1 , Soraya Saleh Gargari1*, Sarang Younesi2 , Parichehr Pooransari1 , Pourandokht Saadati2 , Masoomeh Mirzamoradi1 , Shahram Savad2 , Mohammad Mahdi Taheri Amin2 , Mohammad-Hossein Modarresi3 , Maryam Afrakhteh1 and Soudeh Ghafouri-Fard4*

Abstract

Objectives:

Recent years have witnessed a shift from invasive methods of prenatal screening to non-invasive strategies . Accordingly, non-invasive prenatal testing (NIPT) using cell-free fetal DNA in maternal plasma has gained a considerable deal of interest from both geneticists and obstetricians. Efficacy of this method in identification of common aneuploidies has been extensively assessed in singleton pregnancies. However, a limited number of studies have addressed the twin pregnancies. In this context, the present study is aimed at identification of the efficacy of NIPT in twin pregnancies.

Methods: 

NIPT was performed on twin pregnancies to screen trisomies 13, 18 and 21. Pregnant women referring to Nilou Clinical Laboratory between March 2016 and December 2018 were included in this research 

Results:

In the current study, a total 356 twin pregnancies were screened in search for trisomies 13, 18 and 21. 6 cases exhibited positive NIPT results in which the presence of trisomies 13, 18 and 21 was confirmed by fetal karyotype in 1, 2 and 2 cases, respectively. One twin pregnancy showed normal karyotype. The combined false-positive rate for these trisomies was 0.28%. No false negative case was observed. The combined sensitivity and specificity of NIPT in twin pregnancies were 100 and 99.7%, respectively. 

Conclusion:

The results of the current study verify the feasibility, sensitivity and specificity of NIPT in twin pregnancies.

Keywords: NIPT, Non-invasive prenatal testing, Cell free DNA, Trisomy 21, Trisomy, 18, Trisomy 13, Twin pregnancy

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