PLACENTAL PATHOLOGY OF TRIPLOIDY

Triploidy is a common chromosome abnormality in spontaneous abortions. Previous studies of spontaneous abortions have suggested that approxi mately 85% of triploid abortuses show the placental changes of partial hydatidiform mole (PHM) and that this appearance was associated, poss ibly attributable, to paternal origin of the extra haploid set of chro mosomes. More recent work, however, has shown that most triploidy is t he result of digyny-the extra set of chromosomes originating from the mother. Given the association of PHM with diandry, these results would appear to be at odds with the results of previous studies of placenta l morphology in triploids. The authors reviewed the placental patholog y of all cases of triploidy examined at their institution over a 2-yea r period and established that PRM occurs in a minority of triploid con ceptuses. These results support the findings of studies showing that d igyny is the most common origin of triploidy. Copyright (C) 1996 by W. B. Saunders Company