First-trimester chromosome diagnosis by lavage of the uterine cavity.

Fetal karyotyping of trophoblast cells obtained by lavage of the uterine cavity was evaluated on 86 first-trimester irrigation fluid samples. Villus fragments were observed in 72 fluid samples indicating an 83.7 per cent sampling success rate. The amount of villi in these samples ranged from 1 to 32 mg. In most cases, villus fragments showed degeneration of the external syncytiotrophoblast layer and absence of blood vessels. In the first phase of this study (15 samples), a high degree of maternal cell contamination was observed after long-term cultures. In the following phase (71 samples), this obstacle was overcome by the application of a semi-direct method. Chromosome preparations were set up after 24 h incubation of villus fragments and QFQ-banded metaphase spreads were scored for chromosome number and sex. Sixty samples showed the presence of villus fragments and the fetal karyotype was established in 40. Male and female chromosome complements were observed in 16 and 24 cases, respectively. In four cases, an abnormal fetal karyotype was diagnosed. These included trisomy of chromosomes 13, 15, and 16, and one mosaic with trisomy 12. Our results indicate that first-trimester fetal karyotyping might be feasible by a semi-direct method using chorionic villus fragments obtained at intrauterine lavage.