A freehand ultrasonographically guided technique in transabdominal chorionic villus sampling in more than 24 000 consecutive cases Response
2010
Abstract
CVS availability compared to amniocentesis continues to be limited. Since introduction, CVS has been a 'big deal' with supposedly complicated needle manipulations, an obvious learning curve, and with experience required for success and safety.
The vacutainer method is not such a 'big deal' being quite simple physically and familiar (like amniocentesis)