Detection of maternal DNA in umbilical cord blood by polymerase chain reaction amplification of minisatellite sequences

One of the concerns about the use of cord blood as a source of hematopoietic stem cells for allogeneic transplantation is the possibility of contamination by maternal cells which could cause life-threatening GVHD, We have assessed cord blood contamination using PCR analysis of several minisatellite regions to detect maternal DNA. Eighty mother-cord pairs were obtained for this study. In one case there were no specific maternal alleles at any loci and, therefore, cord blood could not be evaluated. Thus, there was a total of 79 informative cases for the detection of maternal cells in the fetal circulation, In most cases, the level of detection was between 0.5 and 1%. We detected maternal DNA in the cord blood sample in only one case (1.26%), and the analysis of dilution experiments led to an estimate of 0.5-1% maternal cells. In conclusion, using PCR amplification of hypervariable regions, maternal DNA is very rarely detected in the cord blood collected at birth, although this approach has a relatively low level of sensitivity.