Prenatal diagnosis of trisomy 21 through detection of trophoblasts in cervical smears.

Background: Fetal cells exfoliate in the uterine cavity during early pregnancy and are a potential source of material for NIPD.

Aims: This study was designed to test the hypothesis that fetal cells obtained from the uterine cervix during the first trimester of pregnancy could be utilized for prenatal diagnosis of chromosomal aneuploidy.

Study Design: Fetal cells retrieved from the distal endocervical canal during the first trimester of pregnancy were hybridized with chromosome 21 specific FISH probes and analyzed with an automated fluorescence microscope.