Transcervical sampling as a means of detection of fetal cells during the first trimester of pregnancy

OBJECTIVE: Our aim was to evaluate the detection of fetal cells from transcervical samples by means of fluorescence in situ hybridization analysis. STUDY DESIGN: Forty-seven women undergoing first-trimester termination of pregnancy were recruited for transcervical sampling and 16 were recruited for endocervical mucus aspiration. Subjects were asked to assess the discomfort of the procedure. Fluorescence in situ hybridization analyses were performed with X and Y chromosome-specific probes. Results were compared with those of conventional chromosomal analysis. RESULTS: Male signals (XY) were observed in 19 of 25 male fetuses (76%), and female signals (XX) were observed in 21 of 22 female fetuses. There was a significant variation between operators in cell retrieval. With mucus aspiration only 37.5% of male fetuses were correctly identified. The subjects did not find the procedure uncomfortable and reported that it was comparable to having a cervical smear taken. CONCLUSIONS: Transcervical irrigation correctly identified the sex of 76% of male fetuses, but it still has considerable operator variability. This variability might be reduced by improved catheter design.