Abstract: Objective To investigate the value of maternal plasma cell-free fetal DNA (cff-DNA) examination in detection of fetal
chromosomal aneuploidy in pregnant women at advanced maternal ages during the first trimester of pregnancy. Methods A
total of 136 pregnant women (11 to 13+6 gestational weeks) with advanced maternal ages were screened for fetal chromosomal
aneuploidy with ultrasound and maternal plasma cff-DNA examination during March 1, 2011 to August 31, 2013, and the
results were then confirmed by karyotype analysis and fluorescence in situ hybridization (FISH). Results Of the 136 women
examined, cff-DNA screening detected chromosomal aneuploidy in 5 cases, including trisome-21 in 3 cases, trisome-18 in 1
case, and 45,X in 1 case as confirmed subsequently by karyotype analysis. Ultrasound screening reported a normal finding in
one case of trisomy-21, thickening of the NT in the case of trisomy-18, and fetal anasarca in the case of 45,X. Karyotype analysis
and follow-up of the women did not find chromosomal abnormality in the 131 negative cases screened by cff-DNA detection.
Conclusion Screening of materal plasma cff-DNA allows accurate and early detection of fetal chromosomal aneuploidy in
women of advanced maternal ages to avoid unnecessary invasive antenatal examinations.