Pregnancy
Results from the VANISH study: A prospective multicenter study validating a single-nucleotide polymorphism-based noninvasive prenatal test to assess aneuploidy risk in surviving twins of vanishing twin pregnancies
By Dugoff L, Mumford SL, Rochon ML and 22 others.
Abstract
Introduction
To develop and validate a single-nucleotide polymorphism (SNP)-based noninvasive prenatal cell-free DNA (cfDNA) screening algorithm capable of identifying the cfDNA signal of the living fetus in vanishing twin (VT) pregnancies and assessing that twin's aneuploidy risk.
Methods
Prospective study enrolling participants ≥18 years old at ≥9 weeks' gestation with an ultrasound-confirmed VT at 21 US sites (August 2021 to August 2023). The study protocol specified SNP-based cfDNA screening at enrollment and at two additional 3-week intervals. Neonatal buccal swabs evaluated the SNP profile of the living fetus. Cases lost to follow-up and with missing samples were excluded. Using SNP-based technology, an algorithm to identify the living fetus was developed based on the number of fetoplacental cfDNA signals and individual fetal fraction measurements. Concordance between cfDNA in maternal plasma and newborn buccal-swab SNP profiles was used to validate the algorithm in correctly identifying the living fetus. Common aneuploidies and fetal sex were determined for the living fetus.