Prenatal diagnosis by minimally invasive first-trimester transcervical sampling is unreliable, , ,

OBJECTIVE: We investigated whether reliable prenatal diagnosis is possible from fetal cells harvested transcervically in first-trimester pregnancies. STUDY DESIGN: Fetal cells were obtained transcervically from 87 women undergoing pregnancy termination. Fetal gender was determined in 51 pregnancies with three different polymerase chain reaction techniques and in 36 pregnancies with fluorescent in situ hybridization. In known male pregnancies the number of male fetal cells present was also determined. RESULTS: Polymerase chain reaction detected male deoxyribonucleic acid in up to 79% of cases in male pregnancies and up to 45% of cases in female pregnancies. Fetal gender was correctly predicted in up to 72% of cases with fluorescent in situ hybridization. However, fetal cells were identified in <40% of informative male pregnancies and were present in low numbers - 0.7% to 3.4% in swabs and 4.4% to 24.8% in flushes. CONCLUSION: The use of fetal cells obtained by minimally invasive first-trimester transcervical sampling is unreliable for prenatal diagnosis. (Am J Obstet Gynecol 1996;175:382-7.)