Transabdominal placental biopsy in the second and third trimesters of pregnancy : what is the risk of maternal contamination in DNA diagnosis ?

We investigated the risk of maternal contamination in antenatal DNA diagnosis after second- and third-trimester transabdominal placental biopsy. For this purpose, we compared the restriction fragment length polymorphism (RFLP) patterns of 11 chorionic villus DNA samples after late chorionic villus sampling (CVS) with those of the corresponding maternal DNA