Prevalence of tetraploid metaphases in semidirect and cultured chorionic villi

Objective: Investigation of the normal frequency of tetraploid metaphases i n semidirect (STC) and cultured (LTC) chorionic villi, Methods: Fifty metap hases in STC- and in LTC-villi slides of 100 women of advanced maternal age were screened for tetraploidy, Results: Up to three tetraploid metaphases were encountered in 27% of the STC-villi preparations; the scores fitted a Poisson distribution. In all LTC-villi preparations tetraploid cells were s een; the scores fitted a log-Gaussian distribution. Conclusions: On the bas is of these distributions, we propose a protocol for the management of tetr aploid metaphases in chorionic villi, strongly reducing the number of prena tal follow-up investigations. Copyright (C) 2001 S.KargerAG,Basel.