Comparison of cell cultures, chromosome quality and karyotypes obtained after chorionic villus sampling and early amniocentesis with filter technique

548 cell cultures and karyotypes obtained by early amniocentesis with filtration technique (EAF) at a mean gestational age of 12½ weeks were compared with 555 obtained by transabdominal chorionic villus sampling (CVS) at a mean gestational age of 11 weeks. The number of abnormal karyotypes, culture failure rate and harvest time were evaluated. The results were then compared with three similar studies from the literature evaluating early amniotic fluid cultures obtained with conventional techniques compared with chorionic villus cultures. Further, the quality of the chromosome preparations from chorionic villi and early amniotic fluid respectively was compared. More abnormal karyotypes were found among the CVS cultures, which was expected due to earlier sampling and presence of confined placental mosaicism. No ambiguous results were present after EAF. The lowest culture failure rate of 0·2 per cent was found after EAF compared with 0·9 per cent among CVS. EAF also showed a significantly lower culture failure rate when compared with the literature, where early amniocentesis (EA) had been carried out by standard techniques. The time from sampling to harvest was longer in the EAF group (mean 9·5 days) compared with CVS (mean 6·1 days), in accordance with the literature. Nevertheless, the culture time of EAF was significantly shorter than the mean of EA from the comparative studies, whereas CVS culture times showed no differences. Rates of pseudomosaicism, maternal cell contamination, single cell aberrations, number of chromosome bands, mitoses counted and number of primary cultures needed for each karyotype were also compared. We concluded that EAF carried out around 12½ weeks of gestation is a successful method with a lower culture failure rate compared with CVS cultures from 11‐week gestations and with a significantly lower culture failure rate when compared with EA from similar studies. EAF provides chromosome preparations of high quality, and the risk of ambiguous karyotypes is very low. Copyright © 1999 John Wiley & Sons, Ltd.