Collection of villous tissue under ultrasound guidance to improve the cytogenetic study of early pregnancy failure.

The cytogenetic study of spontaneous miscarriage has been limited by poor karyotype success rates obtained from cell culture after surgical evacuation of retained products of conception. The aim of this study was to assess the effect of improving the method of collection of villous tissues at the time of surgery on the karyotype success rate of cell culture. Villous samples were obtained prospectively from a cohort of 170 spontaneous miscarriages at the beginning of the surgical procedure using small biopsy forceps guided into the placenta by ultrasound imaging. This was compared with a retrospective series of 1191 spontaneous miscarriages, cultured in the same laboratory, following conventional collection of the sample from the aspiration recipient after surgery. In the prospective series, six (3.5%) of the original samples were classified by the laboratory as 'decidua only' as compared with 162 (13.6%) in the retrospective series. The karyotype success rate was 94.5% in the prospective series compared with 83.7% in the retrospective series. The karyotype results revealed a chromosome abnormality rate of 65.8% in the prospective group and 64% in the retrospective group with a similar distribution in both groups. Our data show that a karyotype can be obtained from clean villous material collected at the time of surgical evacuation of miscarriage. Thus, it is not justified to subject women to transabdominal chorionic villus sampling to achieve a high karyotype success rate.