Transabdominal chorionic villus sampling: a freehand ultrasound-guided technique.

A simple transabdominal chorionic villus sampling method, carried out with a 20-gauge spinal needle under ultrasound guidance, was evaluated in 100 cases selected for genetic evaluation in the first trimester. Its use was limited to the management of anatomic and clinical conditions that contraindicated transcervical aspiration. The high efficacy of the method was demonstrated by an ability to obtain enough villus tissue for karyotyping in all but one case. In 94% of the cases, only one pass of the needle was required. Although the only complication observed was light bleeding in four cases, the safety of the method needs more extensive evaluation.