A proven case of materno-foetal transfusion determined by cytogenetic and DNA analysis

We report a case of materno-foetal transfusion in a phenotypically normal m ale foetus after death in utero at the 35th week of gestation. We have used cytogenetic and polymerase chain reaction (PCR) microsatellite analysis to determine the presence of maternal cells in foetal blood collected by intr acardiac puncture. In the intracardiac blood sample, maternal cells were es timated to comprise between 5 and 10% of nucleated foetal blood cells. When there is a suspicion of foetal genetic pathology, it is necessary to be aw are that the foetal blood karyotype may be misrepresentative, as the analys ed blood cells can indeed be of maternal origin.