THE OUTCOME OF PREGNANCIES WITH CONFINED PLACENTAL CHROMOSOME MOSAICISM IN CYTOTROPHOBLAST CELLS

Cytogenetic findings and outcome of pregnancy are reported in 108 case s in which confined placental mosaicism (CPM, n=101) or generalized mo saicism (n=7) was found at or after first-trimester chorionic villus s ampling. In all samples, a (semi)direct cytogenetic analysis of cytotr ophoblast cells was performed. Two pregnancies with CPM ended in a spo ntaneous abortion before 28 weeks (1.9 per cent). In 15 cases the preg nancy was terminated: eight cases were shown to be examples of CPM; se ven cases can be considered as examples of generalized mosaicism. A no rmal cytogenetic result was obtained after follow-up amniocentesis in 88 of the remaining 91 cases. In three cases, no amniocentesis was per formed but confirmation of a normal karyotype was obtained in other ce lls. One of the 91 pregnancies was nevertheless terminated for psychos ocial reasons. One child died perinatally and another on the seventh d ay after birth. The birth weight is known for 89 children, the curve s hows a normal distribution. In 11 of these children (12.3 per cent), t he birth weight was found to be below the tenth centile. The outcome i n a subgroup of eight pregnancies with CPM and involvement of chromoso me 13, 16, or 22, however, revealed two fetal losses and four children with a birth weight below the tenth centile (75 per cent).