Techniques for chorionic villus sampling and amniocentesis: a survey of practice in specialist UK centres

Guidelines exist for amniocentesis and chorionic villous sampling (CVS) practice, but there is no consensus regarding individual techniques. Our survey sought to review current practice within specialist centres in the United Kingdom.

RCOG sub-specialist training centres were invited to complete a postal questionnaire, seeking their consultants' primary choices for amniocentesis and CVS techniques. Information sought included needle choice, local anaesthetic (LA), suction methods, quantity of samples obtained; and with regard to CVS, preferred approach [transcervical (TC) or transabdominal (TA)].

Response rate was 96% providing information on 111 consultants (111 amniocentesis/90 CVS). During amniocentesis, 86% use 22G needles and 70% are helped by an assistant who aspirates a set liquor volume (69%). For CVS, 98% use a TA approach, 89% use LA, and 29% an 18G single needle with 38% preferring a 17/19G double needle but no clear consensus regarding the use of assistants.

There is some agreement among specialists in the United Kingdom regarding techniques for invasive prenatal diagnosis. For amniocentesis, most operators use 22G needles, with an assistant to aspirate a set volume of fluid regardless of gestation. For CVS, there is considerable variation in needle choice, although most operators use a TA approach with LA.