Transabdominal chorionic villus sampling in the second trimester.

Transabdominal chorionic villus sampling under ultrasound guidance was carried out in 19 patients in the second trimester. We found that needle size combination 17/19 provided the best results with consistently adequate samples of tissue. Transabdominal chorionic villus sampling is a potentially useful technique for providing relatively rapid prenatal genetic diagnosis in patients at high risk in the second trimester.