Vasa Praevia: Diagnosis And Management Green-Top Guideline No. 27b

Emergency caesarean delivery and neonatal resuscitation, including the use of blood transfusion if required, are essential in the management of ruptured vasa praevia diagnosed during labour. Grade of recommendation: B Placental pathological examination should be performed to confirm the diagnosis of vasa praevia, in particular when stillbirth has occurred or where there has been acute fetal compromise during delivery. [ New 2018 ] Grade of recommendation: ✓ The performance of ultrasound in diagnosing vasa praevia at the time of the routine fetal anomaly scan has a high diagnostic accuracy with a low false-positive rate. [ New 2018 ] Grade of recommendation: B A combination of both transabdominal and transvaginal colour Doppler imaging (CDI) ultrasonography provides the best diagnostic accuracy for vasa praevia. Grade of recommendation: D There is insufficient evidence to support universal screening for vasa praevia at the time of the routine midpregnancy fetal anomaly scan in the general population. Grade of recommendation: D Although targeted midpregnancy ultrasound screening of pregnancies at higher risk of vasa praevia may reduce perinatal loss, the balance of benefit versus harm remains undetermined and further research in this area is required. [ New 2018 ] Grade of recommendation: ✓ Because of the speed at which fetal exsanguination can occur and the high perinatal mortality rate associated with ruptured vasa praevia, delivery should not be delayed while trying to confirm the diagnosis, particularly if there is evidence that fetal wellbeing is compromised. [ New 2018 ] Grade of recommendation: ✓ In the presence of confirmed vasa praevia in the third trimester, elective caesarean section should ideally be carried out prior to the onset of labour. Grade of recommendation: ✓ A decision for prophylactic hospitalisation from 30–32 weeks of gestation in women with confirmed vasa praevia should be individualised and based on a combination of factors, including multiple pregnancy, antenatal bleeding and threatened premature labour. [ New 2018 ] Grade of recommendation: ✓ In cases of vasa praevia that develop premature rupture of membranes and/or labour at viable gestational ages, a caesarean section should be performed without delay. Grade of recommendation: D To avoid unnecessary anxiety, admissions, prematurity and caesarean section, it is essential to confirm persistence of vasa praevia by ultrasound in the third trimester. Grade of recommendation: ✓ The ultimate management goal of confirmed vasa praevia should be to deliver before rupture of membranes while minimising the impact of iatrogenic prematurity. Based on available data, planned caesarean delivery for a prenatal diagnosis of vasa praevia at 34–36 weeks of gestation is reasonable in asymptomatic women. [ New 2018 ] Grade of recommendation: D Administration of corticosteroids for fetal lung maturity should be recommended from 32 weeks of gestation due to the increased risk of preterm delivery. Grade of recommendation: ✓ The purpose of this guideline is to describe the diagnostic modalities and review the evidence-based approach to the clinical management of pregnancies complicated by vasa praevia. Vasa praevia occurs when the fetal vessels run through the free placental membranes. Unprotected by placental tissue or Wharton's jelly of the umbilical cord, a vasa praevia is likely to rupture in active labour, or when amniotomy is performed to induce or augment labour, in particular when located near or over the cervix, under the fetal presenting part.1, 2 Vasa praevia is classified as type I when the vessel is connected to a velamentous umbilical cord, and type II when it connects the placenta with a succenturiate or accessory lobe. Vasa praevia may be diagnosed during early labour by vaginal examination, detecting the pulsating fetal vessels inside the internal os, or by the presence of dark-red vaginal bleeding and acute fetal compromise after spontaneous or artificial rupture of the placental membranes. The fetal mortality rate in this situation is at least 60% despite urgent caesarean delivery. However, improved survival rates of over 95% have been reported where the diagnosis has been made antenatally by ultrasound followed by planned caesarean section.3 Vasa praevia is uncommon in the general population with a prevalence ranging between 1 in 1200 and 1 in 5000 pregnancies, although the condition may have been under-reported.1-6 This guideline was developed in accordance with standard methodology for producing Royal College of Obstetricians and Gynaecologists (RCOG) Green-top Guidelines. The Cochrane Library (including the Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effects [DARE]), EMBASE, Trip, MEDLINE and PubMed (electronic databases) were searched for relevant randomised controlled trials (RCT), systematic reviews and meta-analyses. The search was restricted to articles published between May 2009 and July 2016 (the search for the previous guideline was up to May 2009). A top-up literature search was performed in March 2018. The databases were searched using the relevant Medical Subject Headings (MeSH) terms, including all subheadings, and this was combined with a keyword search. Search words included, ‘vasa praevia’, ‘velamentous cord insertion’ and ‘umbilical cord anomalies’. The search was restricted to humans and the English language. The National Library for Health and the National Guideline Clearinghouse were also searched for relevant guidelines and reviews. Where possible, recommendations are based on available evidence. In the absence of published evidence, these have been annotated as ‘good practice points’. Further information about the assessment of evidence and the grading of recommendations may be found in Appendix I. Emergency caesarean delivery and neonatal resuscitation, including the use of blood transfusion if required, are essential in the management of ruptured vasa praevia diagnosed during labour. Grade of recommendation: B Placental pathological examination should be performed to confirm the diagnosis of vasa praevia, in particular when stillbirth has occurred or where there has been acute fetal compromise during delivery. [New 2018] Grade of recommendation: ✓ The performance of ultrasound in diagnosing vasa praevia at the time of the routine fetal anomaly scan has a high diagnostic accuracy with a low false-positive rate. [ New 2018 ] Grade of recommendation: B A combination of both transabdominal and transvaginal colour Doppler imaging (CDI) ultrasonography provides the best diagnostic accuracy for vasa praevia. Grade of recommendation: D There is insufficient evidence to support universal screening for vasa praevia at the time of the midpregnancy routine fetal anomaly scan in the general population. Grade of recommendation: D Although targeted midpregnancy ultrasound assessment of pregnancies at higher risk of vasa praevia has been investigated, the balance of benefit versus harm remains undetermined and further research in this area is required. [ New 2018 ] Grade of recommendation: ✓ Because of the speed at which fetal exsanguination can occur and the high perinatal mortality rate associated with ruptured vasa praevia, delivery should not be delayed while trying to confirm the diagnosis, particularly if there is evidence that fetal wellbeing is compromised. [ New 2018 ] Grade of recommendation: ✓ In the presence of confirmed vasa praevia in the third trimester, elective caesarean section should ideally be carried out prior to the onset of labour. Grade of recommendation: ✓ A decision for prophylactic hospitalisation from 30–32 weeks of gestation in women with confirmed vasa praevia should be individualised and based on a combination of factors, including multiple pregnancy, antenatal bleeding and threatened premature labour. [ New 2018 ] Grade of recommendation: ✓ In cases of vasa praevia that develop premature rupture of membranes and/or labour at viable gestational ages, a caesarean section should be performed without delay. Grade of recommendation: D To avoid unnecessary anxiety, admissions, prematurity and caesarean section, it is essential to confirm persistence of vasa praevia by ultrasound in the third trimester. Grade of recommendation: ✓ Delivery by caesarean section of women with confirmed vasa praevia is intuitive and logical, and not based on RCTs.12 The ultimate management goal of confirmed vasa praevia should be to deliver before rupture of membranes while minimising the impact of iatrogenic prematurity. Based on available data, planned caesarean delivery for a prenatal diagnosis of vasa praevia at 34–36 weeks of gestation is reasonable in asymptomatic women. [ New 2018 ] Grade of recommendation: D Administration of corticosteroids for fetal lung maturity should be recommended from 32 weeks of gestation due to the increased risk of preterm delivery. Grade of recommendation: ✓ Postnatal follow-up should include debriefing with an explanation of what happened, why it happened and any implications for future pregnancy. Raising awareness about the clinical risk factors of vasa praevia should be pursued locally, including organising policies or guidelines for flagging up women at risk and arranging for them to see a specialist consultant when suspected. There should be appropriate training for ultrasound staff in the antenatal diagnosis of vasa praevia. There should be written protocols for the identification of and planning further care of women diagnosed with vasa praevia. Clinical guidelines are: ‘systematically developed statements which assist clinicians and patients in making decisions about appropriate treatment for specific conditions’. Each guideline is systematically developed using a standardised methodology. Exact details of this process can be found in Clinical Governance Advice No.1 Development of RCOG Green-top Guidelines (available on the RCOG website at http://www.rcog.org.uk/green-top-development). These recommendations are not intended to dictate an exclusive course of management or treatment. They must be evaluated with reference to individual patient needs, resources and limitations unique to the institution and variations in local populations. It is hoped that this process of local ownership will help to incorporate these guidelines into routine practice. Attention is drawn to areas of clinical uncertainty where further research may be indicated. The evidence used in this guideline was graded using the scheme below and the recommendations formulated in a similar fashion with a standardised grading scheme. A body of evidence including studies rated as 2++ directly applicable to the target population, and demonstrating overall consistency of results; or Extrapolated evidence from studies rated as 1++ or 1+ A body of evidence including studies rated as 2+ directly applicable to the target population, and demonstrating overall consistency of results; or Extrapolated evidence from studies rated as 2++ Evidence level 3 or 4; or Extrapolated evidence from studies rated as 2+ This guideline was produced on behalf of the Royal College of Obstetricians and Gynaecologists by: Professor ERM Jauniaux FRCOG, London (Lead Developer); Professor Z Alfirevic FRCOG, Liverpool, UK; Mr AG Bhide FRCOG, London, UK; Professor GJ Burton, University of Cambridge, UK; Professor SL Collins MRCOG, Oxford, UK; Professor R Silver, University of Utah, Salt Lake City, Utah, USA and peer reviewed by: Professor ML Brizot, University of São Paulo, São Paulo, Brazil; Professor J Dashe, University of Texas Southwestern Medical Center, Dallas, TX, USA; Dr D Fraser FRCOG, Norwich; Dr J Hasegawa, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan; Dr YY Hu, Sichuan University, Chengdu, Sichuan, China; Dr F Malik MRCOG, Southend; Professor P Martinelli, Università di Napoli Federico II, Naples, Italy; RCOG Women's Network; Dr R Salim, Emek Medical Center, Afula, Israel; Dr JT Thomas FRANZCOG, CMFM, Mater Mothers’ Hospital, Brisbane, Australia; Mr N Thomson, Society and College of Radiographers, London; Dr M Tikkanen, Women′s Clinic, Helsinki University Hospital Finland, Helsinki, Finland; UK National Screening Committee; Vasa Praevia Ireland Support and Awareness Group; and Vasa Praevia Raising Awareness for the UK and the International Vasa Previa Foundation; Dr SG Vitale, University of Catania, Catania, Italy. [Correction added on 14 March 2019, after first online publication: SG Vitale has been added to peer reviewers.] Committee lead reviewers were: Dr A McKelvey MRCOG, Norfolk; and Mr RJ Fernando FRCOG, London The chairs of the Guidelines Committee were: Dr MA Ledingham MRCOG, Glasgow1; Dr B Magowan FRCOG, Melrose1; and Dr AJ Thomson MRCOG, Paisley2. 1co-chairs from June 2018 2until May 2018. 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/guidelines-research-services/guidelines/gtg27b/. The final version is the responsibility of the Guidelines 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 Guidelines 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.