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Amniocentesis and chorionic villus sampling

2021; Wiley; Volume: 129; Issue: 1 Linguagem: Inglês

10.1111/1471-0528.16821

1471-0528

Kate Navaratnam, Žarko Alfirević,

Congenital Anomalies and Fetal Surgery

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. Women should be informed that the additional risk of miscarriage following amniocentesis or CVS performed by an appropriately trained operator is likely to be below 0.5%. [Grade B] Amniocentesis should not be performed prior to 15+0 weeks' gestation. [Grade A] CVS should not be performed prior to 10+0 weeks' gestation. [Grade D] Where possible, to reduce the risk of technical challenges, CVS should be performed from 11+0 weeks' gestation onwards. [Good Practice Point] Women with multiple pregnancies should be informed that the additional risk of miscarriage for twin pregnancy following CVS or amniocentesis performed by an appropriately trained operator is around 1%. [Grade B] Screening results for blood borne viruses, viral load and antigen test results should be reviewed when an invasive test is considered and individualised risk of viral transmission should be discussed. [Grade C] The aim of this guideline is to provide a concise set of evidence-based standards for provision and performance of amniocentesis and chorionic villus sampling (CVS) used for prenatal diagnosis. An infographic (Inforgrpahic S1) of this guideline is available as supplemental information, and an audio version at www.rcog.org.uk/gtg8. Pregnant women are offered amniocentesis or 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. Implementation of national combined aneuploidy screening and increasing use of cell free DNA testing from maternal blood has resulted in a significant decline in screen positive results and therefore fewer invasive prenatal tests are being carried out. However, both CVS and amniocentesis remain, at present, the only definitive diagnostic tests for aneuploidy in pregnancy. CVS, carried out to obtain placental villi for analysis, 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; a video demonstrating the recommended technique for transabdominal CVS is available online at www.rcog.org.uk/gtg8. Amniocentesis, performed to obtain amniotic fluid for analysis, is usually offered from 15+0 weeks; a video demonstrating the recommended technique for amniocentesis is available online at www.rcog.org.uk/gtg8. Informed written consent is advised prior to either procedure, and should be in line with existing consent advice from the GMC and Royal College of Obstetricians and Gynaecologists recommendations.1, 2 The consent process must include procedure risks, timing and method of communicating results, sample/tissue storage, benefits, alternatives and option to opt out. Wherever possible contemporaneous local data for procedure related complications should be quoted. Women should receive information on aftercare including, where appropriate, the need for prophylactic anti D in non-sensitised rhesus negative women and indications to seek medical advice following the procedure. The Cochrane Library (including the Cochrane Database of Systematic Reviews), EMBASE, Medline and PubMed electronic databases were searched for relevant meta-analyses, systematic reviews, randomised controlled trials (RCTs), and cohort studies. TRIP, NICE evidence and the Guideline International Network were searched to identify relevant guidelines. Databases were searched for the terms ‘amniocentesis’ and ‘chorionic villus sampling’ appearing in the title or abstract. The search was limited to humans and the English language. The search was restricted to articles published until October 2019. The full search strategy is available to view online as supporting information (Appendix S1 and S2). The recommendations given in this guideline have been graded according to the guidance for the development of RCOG Green-top Guideline.3 The scope of this guideline is confined to technical aspects of the two procedures. For the woman and her family, good care in these circumstances encompasses more than the procedure. Women facing either procedure are usually anxious and clinicians should bear this in mind. The RCOG, Royal College of Midwives (RCM) and Society and College of Radiographers have produced a consensus statement on supporting women and their partners through prenatal screening which,4 while developed to support the evaluative roll-out of non-invasive prenatal testing (NIPT) for Down's syndrome, Edwards' syndrome and Patau's syndrome within the NHS fetal anomaly screening programme, is also relevant to the provision of amniocentesis and CVS. Women should be aware that the results of CVS can be affected by confined placental mosaicism in 1–2% of cases. If there is a fetal structural anomaly, it is reasonable to move forward with discussions regarding ongoing care, including the option of termination of pregnancy if the woman or couple wish to consider this. If there are no structural anomalies, and QFPCR results following CVS suggest a chromosomal anomaly, a full karyotype should be awaited before any decisions are made. Discussions under these circumstances should reflect the RCOG, RCM and Society and College of Radiographers consensus statement on prenatal testing.4 Individual laboratories have reported increased risk of obtaining low quantities of DNA from direct extraction when amniocentesis is performed before 16+0 weeks. Clinicians should be aware of the potential for impact on turn-around-time for results to allow informed discussions during the consent process for procedures carried out before 16+0 weeks. There are insufficient data available to comment on procedure-related risks for higher order multiple pregnancies. KN has declared no conflicts of interest. ZA has declared no conflicts of interest. Full disclosure of interests are available to view online as supporting information. All those involved in the development of the Green-top Guideline, including the Guideline Committee, Guideline Committee co-chairs, guideline developers, peer reviewers and other reviewers, are unpaid volunteers and receive no direct funding for their work in producing the guideline. The exception to this are the RCOG staff involved who are salaried employees of the College and Guideline Committee members who receive reimbursement for expenses for attending Guideline Committee meetings. See more information on travel expense rules on the RCOG website. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. This guideline was produced on behalf of the Royal College of Obstetricians and Gynaecologists by: Dr Kate Navaratnam MRCOG, Liverpool and Professor Zarko Alfirevic FRCOG, Liverpool and peer reviewed by: Mr D Fraser FRCOG, Norwich; Dr N Potdar FRCOG, Leicester; Dr E S Cooper FRCOG, Edinburgh; Dr G Kumar FRCOG, Wrexham; Dr A Pickersgill, FRCOG, Manchester; Mr B Kumar FRCOG, Wrexham; Sabrina O'Dwyer MRCOG, London; Ms C Lloyd, Oxford; Dr M Casillas Barrera COMEGO, México; Mr S Karavolos MRCOG, Salford; G Salsi, University of Bologna, Italy; UK National Screening Committee; British Maternal & Fetal Medicine Society. Committee lead reviewers were: Mr S Karavolos MRCOG, Manchester and Mr A McKelvey MRCOG, Norwich. The Co-Chairs of the Guideline Committee were: Dr MA Ledingham FRCOG, Glasgow and Dr B Magowan FRCOG, Melrose. All RCOG guidance developers are asked to declare any conflicts of interest. A statement summarising any conflicts of interest for this guideline is available from: https://www.rcog.org.uk/en/guidelinesresearch-services/guidelines/gtg8/ The final version is the responsibility of the Guideline Committee of the RCOG. The guideline will be considered for update 3 years after publication, with an intermediate assessment of the need to update 2 years after publication. The Royal College of Obstetricians and Gynaecologists produces guidelines as an educational aid to good clinical practice. They present recognised methods and techniques of clinical practice, based on published evidence, for consideration by obstetricians and gynaecologists and other relevant health professionals. The ultimate judgement regarding a particular clinical procedure or treatment plan must be made by the doctor or other attendant in the light of clinical data presented by the patient and the diagnostic and treatment options available. This means that RCOG Guideline are unlike protocols or guidelines issued by employers, as they are not intended to be prescriptive directions defining a single course of management. Departure from the local prescriptive protocols or guidelines should be fully documented in the patient's case notes at the time the relevant decision is taken.