MATERNAL SERUM SCREENING AND TRISOMY-16 CONFINED TO THE PLACENTA

Five cases of trisomy 16 confined to the placenta have been detected b y invasive procedures (amniocentesis and chorionic villus sampling) af ter high-risk results for Down syndrome and neural tube defects in a m aternal serum screening programme of 6614 consecutive cases. All five pregnancies displayed unusually elevated levels of human chorionic gon adotropin and four out of five also had raised alpha-fetoprotein value s. No structural malformation was present but all five pregnancies wer e complicated by fetal growth retardation, and one by intrauterine dea th. From our results, we suggest that both amniocentesis and chorionic villus sampling should be considered in the management of cases with high mid-trimester levels of these analytes.