Prospective first-trimester screening for trisomies by cell-free DNA testing of maternal blood in twin pregnancy

摘要

Objectives First, to examine in twin pregnancies the performance of first-trimester screening for fetal trisomies 21, 18 and 13 by cell-free (cf) DNA testing of maternal blood and, second, to compare twin and singleton pregnancies regarding the distribution of fetal fraction of cfDNA and rate of failure to obtain a result.