Prevalence of maternal cell contamination in amniotic fluid samples

AbstractPurpose: The purpose of this study is to evaluate the incidence of maternal cell contamination (MCC) in the first few milliliters of amniotic fluid withdrawn during amniocentesis.Methods: A prospective observational study was performed. The initial 2–3 ml of amniotic fluid withdrawn during amniocentesis was divided into direct analysis (uncultured) and cultured samples. A matching maternal buccal swab was obtained for MCC testing. MCC was determined by short-tandem repeat analysis. The primary outcome was measurement of clinically significant contamination (MCC >5%). Secondary outcomes included the determination of risk factors associated with MCC >5%. Outcomes were assessed by fisher’s exact, independent t-test, binary logistic regression, and ANOVA.Results: Direct analysis measured clinically significant contamination (MCC > 5%) in 26% of specimens, while any amount of MCC was present in 68% of specimens. Cultured specimens had MCC > 5% in 2%, and any amount of MCC in 24%. Only blood-tinged flui...