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Amniocentesis and Chorionic Villus Sampling (Green-top Guideline No. 8)

Published: 25/10/2021

Green-top Guideline No. 8: Amniocentesis and Chorionic Villus Sampling

This guideline sets a series of evidence-based standards to ensure a high level and consistency of practice in the provision and performance of amniocentesis and chorionic villus sampling (CVS).

Access the web version of this guideline on Wiley

Access the PDF version of this guideline on Wiley

Audio version

https://soundcloud.com/rcobsgyn/gtg8

This update was undertaken as part of the regular updates to Green-top Guidelines as outlined in our document Developing a Green-top Guideline: Guidance for developers (PDF) and prior to the emergence of the new COVID-19 coronavirus.

Please note that the information provided in this update will be considered for update 3 years after publication, with an intermediate assessment of the need to update 2 years after publication.

Version and edition

This is an update of the 2010 version of this guideline in the new format. It is the fifth edition, which was previously published in October 1996, February 2000, January 2005 and June 2010.

Description

Pregnant women are offered amniocentesis or chorionic villus sampling (CVS) for prenatal diagnosis for a variety of reasons including a higher chance aneuploidy screening result, fetal structural anomaly, or a known risk of inherited genetic disease.

CVS is usually performed between 11+0 and 13+6 weeks of gestation. If required, CVS can be performed between 14+0 and 14+6 weeks’ gestation. Individualised counselling of the merits of CVS versus amniocentesis should be provided for women considering CVS during this time period. Amniocentesis, performed to obtain amniotic fluid for analysis, is usually offered from 15+0 weeks.

Common terms

Amniocentesis, chorionic villus sampling, prenatal testing

Declarations of interest

Dr K Navaratnam: None declared.

Professor Z Alfirevic: None declared.

 

Videos

Demonstration of the recommended technique for amniocentesis

Demonstration of the recommended technique for transabdominal CVS

Key points

Graphic 01 for GTG8 showing a circle with 0.5% written inside

Women should be informed that the additional risk of miscarriage following amniocentesis or CVS performed by a skilled operator is likely to be below 0.5%.

Graphic 02 for GTG8 showing a calendar icon

Amniocentesis should not be performed prior to 15+0 weeks gestation.

CVS should be performed between 11+0 and 13+6 weeks; it should not be performed prior to 10+0 weeks gestation.

Graphic 03 for GTG8 showing two fetuses upside down in the womb

Women with multiple pregnancies should be informed that the additional risk of miscarriage for twin pregnancy following CVS or amniocentesis performed by a skilled operator is around 1%.

Graphic 04 for GTG8 showing a typical virus shape

When an invasive test is considered, screening results for blood borne viruses, viral load and antigen test results should be reviewed and individualised risk of viral transmission should be discussed.

Graphic 05 for GTG8 showing hands and a medical kit

Women considering amniocentesis or CVS should receive detailed counselling and pregnancy mapping by suitably trained healthcare professionals.

Graphic 06 for GTG8 showing a checklist

Care for women who consent to have a CVS or amnioncentesis should be organised in accordance with National Screening Committee Standards.