Clinical significance of placenta-confined nonmosaic trisomy 16.

Since the introduction of chorionic villi sampling in 1984 we have observed five first-trimester cases of nonmosaic placenta confined trisomy 16. At subsequent follow-up it appeared that all five had an adverse maternal or fetal outcome. In three cases the mother had preeclampsia. Two of the infants were born with multiple congenital abnormalities, including tetralogy of Fallot. All children were growth retarded.