<prompt> A women undergoes a chorionic villous sampling at 11 weeks gestation. The result shows two cell lines - 46 xy and 47 xy 21 what is your next stepRepeat CVS at 13 weeks gestationNo need to evaluate furtherDo amniocentesis for further confirmationDiagnose as Down syndrome and counsel the couple  <response>: This is a case of mosaicism. In most cases, the mosaicism reflects confined placental mosaicism rather than true second cell line within fetus.Amniocentesis should be offered, and if results are normal, mosaicism is presumed to be confined to placenta.Confined placental mosaicism can cause IUGR and stillbirth. 