Abstract: A catheter is provided for sampling, and particularly for sampling chorionic villi. The catheter has a cannula of a material opaque to ultrasound and having a distal portion capable of being curved manually into a desired curvature for use, and defining a lumen extending throughout the length of the cannula for containing a supple obturator to close the distal end of the lumen during insertion and to permit removal of the sample by applying a negative pressure to the proximal end of the catheter once the catheter is in position and the obturator removed.