A practical assessment of ultrasound-guided transcervical aspiration of chorionic villi and subsequent chromosomal analysis.

Aspiration biopsy of trophoblastic villi was performed on 56 patients immediately preceding suction termination of pregnancy, using a malleable metal cannula and ultrasound guidance. Villi were obtained from 47 patients (84%), with sampling success rising to 93% after experience. Immediate complications were noted in 14% of patients and correlated with placental positions situated furthest from the cervical canal. Karyotyping from cultured and/or direct preparations was attempted on the villus samples and was successful in 42. Clarity of the karyotypes obtained from direct preparations in this series was not found to be adequate for diagnostic purposes. A number of practical suggestions which facilitate chorion villus sampling are described.