Temporal persistence and long-term effect on noninvasive prenatal
testing by residual fetal cell-free DNA of demised co-twin after
selective fetal reduction in dichorionic diamniotic twin pregnancies
Abstract
Objectives: To determine the temporal persistence of residual cell-free
DNA (cfDNA) of deceased co-twin in maternal circulation after selective
fetal reduction and evaluate its long-lasting effect on noninvasive
prenatal testing (NIPT) results. Design: Prospective observational study
Setting: The Third Affiliated Hospital of Guangzhou Medical University
Population: Dichorionic diamniotic twins (n=5) underwent selective fetal
reduction of a co-twin with trisomy. Methods: With consent, maternal
blood was collected immediately before reduction and periodically after
reduction until birth. CfDNA of each maternal blood sample was sequenced
for NIPT and analyzed for fetal trisomies and fetal fractions. Main
Outcome Measured: Detectable T-scores for trisomy identification and
three types of fetal fractions including the total fetal fraction, the
fetal fraction of the deceased co-twin, and the fetal fraction of the
surviving co-twin.