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BMJ Open Jul 2020Vasa previa is a condition where fetal blood vessels run unprotected in the membranes, outside the umbilical cord, and cross the internal opening of the cervix. During...
INTRODUCTION
Vasa previa is a condition where fetal blood vessels run unprotected in the membranes, outside the umbilical cord, and cross the internal opening of the cervix. During rupture of membranes, these vessels can rupture and put the baby at serious risk of severe blood loss and death. Numerous studies are being conducted to improve diagnostic modalities and establish clear management plans to improve pregnancy outcomes. However, the lack of a standardised set of outcomes for studies on vasa previa makes it difficult to compare study findings and draw meaningful conclusions. Through this project, we will be developing a core outcome set for studies on pregnant women with vasa previa (COVasP).
METHODS AND ANALYSIS
The development of COVasP will involve five steps. The first will be a systematic review, in which we will generate a long list of outcomes based on published studies in pregnancies complicated with vasa previa. The second will involve in-depth interviews with current and former patients, their family members and healthcare providers who care for these patients. This will be followed by a two-round Delphi survey, which will aim to narrow down the long list of outcomes into those considered important by four groups of 'stakeholders': (1) patients, family members and patient advocates/representatives, (2) healthcare providers, (3) researchers, epidemiologists and methodologists and (4) other stakeholders directly or indirectly involved in the management of these pregnancies such as administrators, guideline developers and policymakers. The fourth step will involve a face-to-face consensus meeting using a nominal group approach to establish a finalised core outcome set. The final step will involve measuring and defining the identified outcomes using a combination of systematic reviews and Delphi surveys.
ETHICS AND DISSEMINATION
This study as well as consent forms for stakeholder participation have received approval from the Mount Sinai Hospital Research Ethics Board (REB number 18-0173-E) on 05 September 2018 and the Human Research Ethics Committee at The University of Technology Sydney, Australia on 30 July 2019 (UTS HREC reference number ETH19-3718). All progress will be documented on the international prospective register of systematic reviews and Core Outcome Measures in Effectiveness Trials databases. REGISTRATION DETAILS: http://www.comet-initiative.org/studies/details/1117.
Topics: Consensus Development Conferences as Topic; Delphi Technique; Female; Humans; Interviews as Topic; Pregnancy; Pregnancy Complications, Cardiovascular; Pregnancy Outcome; Research Design; Stakeholder Participation; Systematic Reviews as Topic; Vasa Previa
PubMed: 32690497
DOI: 10.1136/bmjopen-2019-034018 -
Systematic Reviews Jun 2020Velamentous cord insertion (VCI) is an umbilical cord attachment to the membranes surrounding the placenta instead of the central mass. VCI is strongly associated with... (Review)
Review
BACKGROUND
Velamentous cord insertion (VCI) is an umbilical cord attachment to the membranes surrounding the placenta instead of the central mass. VCI is strongly associated with vasa praevia (VP), where umbilical vessels lie in close proximity to the internal cervical os. VP leaves the vessels vulnerable to rupture, which can lead to fatal fetal exsanguination. Screening for VP using second-trimester transabdominal sonography (TAS) to detect VCI has been proposed. We conducted a rapid review investigating the quality, quantity and direction of evidence available on the epidemiology, screening test accuracy and post-screening management pathways for VCI.
METHODS
MEDLINE, Embase and the Cochrane Library were searched on 5 July 2016 and again on 11 October 2019, using general search terms for VP and VCI. Only peer-reviewed articles reporting on the epidemiology of VCI, the accuracy of the screening test and/or downstream management pathways for VCI pregnancies were included. Quality and risk of bias of each included study were assessed using pre-specified tools.
RESULTS
Forty-one relevant publications were identified; all but one were based on non-UK pregnancy cohorts, and most included relatively few VCI cases. The estimated incidence of VCI was 0.4-11% in singleton pregnancies, with higher incidence in twin pregnancies (1.6-40%). VCI incidence was also increased among pregnancies with one or more other risk factors, including in vitro fertilisation pregnancies or nulliparity. VCI incidence among women without any known risk factors was unclear. VCI was associated with adverse perinatal outcomes, most notably pre-term birth and emergency caesarean section in singleton pregnancies, and perinatal mortality in twins; however, associations varied across studies and the increased risk was typically low or moderate compared with pregnancies without VCI. In studies on limited numbers of cases, screening for VCI using TAS had good overall accuracy, driven by high specificity. No studies on post-screening management of VCI were identified.
CONCLUSIONS
Literature on VCI epidemiology and outcomes is limited and low-quality. The accuracy of second-trimester TAS and the benefits and harms of screening cannot be determined without prospective studies in large cohorts. Modelling studies may indicate the feasibility and value of studying the epidemiology of VCI and the potential impact of detecting VCI as part of a population screening programme for VP.
Topics: Cesarean Section; Female; Humans; Incidence; Pregnancy; Prospective Studies; Risk Factors; Vasa Previa
PubMed: 32576295
DOI: 10.1186/s13643-020-01355-0 -
Prenatal Diagnosis Dec 2020
Topics: Female; Humans; Pregnancy; Ultrasonography, Doppler, Color; Ultrasonography, Prenatal; Vasa Previa
PubMed: 32557595
DOI: 10.1002/pd.5771 -
Taiwanese Journal of Obstetrics &... Jan 2020
Topics: Adult; Cervix Uteri; Female; Humans; Labor Presentation; Placenta; Pregnancy; Ultrasonography, Prenatal; Umbilical Cord
PubMed: 32039791
DOI: 10.1016/j.tjog.2019.10.001 -
Obstetrics and Gynecology Mar 2020Umbilical cord abnormalities are commonly cited as a cause of stillbirth, but details regarding these stillbirths are rare. Our objective was to characterize stillbirths...
OBJECTIVE
Umbilical cord abnormalities are commonly cited as a cause of stillbirth, but details regarding these stillbirths are rare. Our objective was to characterize stillbirths associated with umbilical cord abnormalities using rigorous criteria and to examine associated risk factors.
METHODS
The Stillbirth Collaborative Research Network conducted a case-control study of stillbirth and live births from 2006 to 2008. We analyzed stillbirths that underwent complete fetal and placental evaluations and cause of death analysis using the INCODE (Initial Causes of Fetal Death) classification system. Umbilical cord abnormality was defined as cord entrapment (defined as nuchal, body, shoulder cord accompanied by evidence of cord occlusion on pathologic examination); knots, torsions, or strictures with thrombi, or other obstruction by pathologic examination; cord prolapse; vasa previa; and compromised fetal microcirculation, which is defined as a histopathologic finding that represents objective evidence of vascular obstruction and can be used to indirectly confirm umbilical cord abnormalities when suspected as a cause for stillbirth. We compared demographic and clinical factors between women with stillbirths associated with umbilical cord abnormalities and those associated with other causes, as well as with live births. Secondarily, we analyzed the subset of pregnancies with a low umbilical cord index.
RESULTS
Of 496 stillbirths with complete cause of death analysis by INCODE, 94 (19%, 95% CI 16-23%) were associated with umbilical cord abnormality. Forty-five (48%) had compromised fetal microcirculation, 27 (29%) had cord entrapment, 26 (27%) knots, torsions, or stricture, and five (5%) had cord prolapse. No cases of vasa previa occurred. With few exceptions, maternal characteristics were similar between umbilical cord abnormality stillbirths and non-umbilical cord abnormality stillbirths and between umbilical cord abnormality stillbirths and live births, including among a subanalysis of those with hypo-coiled umbilical cords.
CONCLUSION
Umbilical cord abnormalities are an important risk factor for stillbirth, accounting for 19% of cases, even when using rigorous criteria. Few specific maternal and clinical characteristics were associated with risk.
Topics: Adult; Case-Control Studies; Female; Humans; Pregnancy; Stillbirth; Umbilical Cord; United States; Young Adult
PubMed: 32028503
DOI: 10.1097/AOG.0000000000003676 -
Revue Medicale de Liege Jan 2020Velamentous cord insertion is a rare placental abnormality, that may be associated with vasa praevia, i.e. the presence of an umbilical vessel near the internal cervical...
Velamentous cord insertion is a rare placental abnormality, that may be associated with vasa praevia, i.e. the presence of an umbilical vessel near the internal cervical orifice. In case of spontaneous rupture of the membranes, there is a major risk of fetal haemorrhage, which is often lethal for the unborn baby. The challenge of care is based on the prenatal diagnosis during the 2nd trimester ultrasound. In case a vasa praevia is confirmed during the 3rd trimester, elective caesarean section should be carried out prior to the onset of labour, between 34 and 36 weeks of pregnancy. Corticosteroid treatment for fetal lung maturation is recommended at 32 weeks of gestation because of the increased risk of preterm delivery. Velamentous cord insertion may be associated with other adverse pregnancy outcomes such as intrauterine growth restriction, death in utero, placental abnormalities.
Topics: Cesarean Section; Female; Humans; Infant, Newborn; Pregnancy; Pregnancy Outcome; Prenatal Diagnosis; Ultrasonography, Prenatal; Vasa Previa
PubMed: 31920037
DOI: No ID Found -
Systematic Reviews Dec 2019The UK National Screening Committee (UK NSC) reviews evidence about existing or potential population screening programmes using rapid review products called evidence...
BACKGROUND
The UK National Screening Committee (UK NSC) reviews evidence about existing or potential population screening programmes using rapid review products called evidence summaries. We provide a case report as an example of how rapid reviews are developed within the UK NSC's process, consider how the quality of rapid reviews should be assessed and ask whether the rapid review was an appropriate tool to inform the UK NSC's decision-making process.
METHODS
We present the rapid review approach taken by the commissioner and the reviewers to develop an evidence summary for vasa praevia (VP), which the UK NSC reappraised as part of its 3-yearly cycle for conditions where screening is currently not recommended. We apply the AMSTAR 2 quality appraisal checklist for systematic reviews, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and a published checklist of items to consider with a rapid review approach. As UK NSC evidence summaries do not include meta-analyses, any related AMSTAR 2 or PRISMA checklist items were considered inapplicable.
RESULTS
The evidence summary was available within the required timelines and highlighted little change from the previous review in terms of key evidence gaps relating to the epidemiology of VP, the screening test and the management pathway. Therefore, the UK NSC concluded that there was insufficient evidence to support a change in its previous recommendation against screening. The evidence summary scored moderately against the applicable AMSTAR 2 and PRISMA checklist items. Against the published checklist of items to consider with a rapid review approach, the evidence summary performed well.
CONCLUSIONS
In this case report, the use of a rapid review as part of the UK NSC's process enabled a pragmatic approach to assessing the overall volume, quality and direction of literature on key questions relating to the viability of a population screening programme for VP. Based on our assessments of this single evidence summary, systematic review quality appraisal tools may undervalue rapid reviews. The validity of the methods used in this case report, as well as the wider generalisability of our insights relating to rapid review practice, reporting and quality assessment, requires analysis of a larger sample of rapid reviews.
Topics: Female; Humans; Mass Screening; Pregnancy; Research Report; Review Literature as Topic; Time Factors; United Kingdom; Vasa Previa
PubMed: 31884972
DOI: 10.1186/s13643-019-1244-9 -
Ultrasound in Obstetrics & Gynecology :... May 2020To examine the feasibility and effectiveness of a two-stage ultrasound screening strategy for detection of vasa previa and to estimate the potential impact of screening...
OBJECTIVES
To examine the feasibility and effectiveness of a two-stage ultrasound screening strategy for detection of vasa previa and to estimate the potential impact of screening on prevention of stillbirth.
METHODS
This was a retrospective study of data from prospective screening for vasa previa in singleton pregnancies, undertaken at the Fetal Medicine Unit at Medway Maritime Hospital, UK, between 2012 and 2018. Women booked for prenatal care and delivery in our hospital had routine ultrasound examinations at 11-13 and 20-22 weeks' gestation. Those with velamentous cord insertion at the inferior part of the placenta at the first-trimester scan and those with low-lying placenta at the second-trimester scan were classified as high-risk for vasa previa and had transvaginal sonography searching specifically for vasa previa, at the time of the 20-22-week scan. The management and outcome of cases with suspected vasa previa is described. We excluded cases of miscarriage or termination at < 24 weeks' gestation.
RESULTS
The study population of 26 830 singleton pregnancies included 21 (0.08%; 1 in 1278) with vasa previa. In all cases of vasa previa, the diagnosis was made at the 20-22-week scan and confirmed postnatally by gross and histological examination of the placenta. At the 11-13-week scan, cord insertion was classified as central in 25 071 (93.4%) cases, marginal in 1680 (6.3%), and velamentous in 79 (0.3%). In 16 (76.2%) of the 21 cases of vasa previa, cord insertion at the first-trimester scan was classified as velamentous at the inferior part of the placenta, in two cases (9.5%) as marginal and in three cases (14.3%) as central. The 21 cases of vasa previa were managed on an outpatient basis with serial scans for measurement of cervical length and elective Cesarean section at 34 weeks' gestation; all babies were liveborn but there was one neonatal death. In the study population, there were 83 stillbirths, none of which had evidence of vasa previa on postnatal examination. On the assumption that, if we had not diagnosed prenatally all 21 cases of vasa previa in our population, half of these cases would have resulted in stillbirth, then the potential impact of screening is prevention of 10.6% (10/94) of stillbirths.
CONCLUSION
A two-stage strategy of screening for vasa previa can be incorporated into routine clinical practice, and such a strategy could potentially reduce the rate of stillbirth. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
Topics: Adult; Feasibility Studies; Female; Fetal Death; Gestational Age; Humans; Infant, Newborn; Placenta Diseases; Pregnancy; Pregnancy Trimester, First; Pregnancy Trimester, Second; Prospective Studies; Retrospective Studies; Stillbirth; Ultrasonography, Prenatal; Vasa Previa
PubMed: 31840871
DOI: 10.1002/uog.21953 -
Ultrasound in Obstetrics & Gynecology :... Apr 2020To explore whether early first-trimester ultrasound can predict the third-trimester sonographic stage of placenta accreta spectrum (PAS) disorder and to elucidate...
OBJECTIVES
To explore whether early first-trimester ultrasound can predict the third-trimester sonographic stage of placenta accreta spectrum (PAS) disorder and to elucidate whether combining first-trimester ultrasound findings with the sonographic stage of PAS disorder can stratify the risk of adverse surgical outcome in women at risk for PAS disorder.
METHODS
This was a retrospective analysis of prospectively collected data from women with placenta previa, and at least one previous Cesarean delivery (CD) or uterine surgery, for whom early first-trimester (5-7 weeks' gestation) ultrasound images could be retrieved. The relationship between the position of the gestational sac and the prior CD scar was assessed using three sonographic markers for first-trimester assessment of Cesarean scar (CS) pregnancy, reported by Calí et al. (crossover sign (COS)), Kaelin Agten et al. (implantation of the gestational sac on the scar vs in the niche of the CS) and Timor-Tritsch et al. (position of the center of the gestational sac below vs above the midline of the uterus), by two different examiners blinded to the final diagnosis and clinical outcome. The primary aim of the study was to explore the association between first-trimester ultrasound findings and the stage of PAS disorder on third-trimester ultrasound. Our secondary aim was to elucidate whether the combination of first-trimester ultrasound findings and sonographic stage of PAS disorder can predict surgical outcome. Logistic regression analysis and area under the receiver-operating-characteristics curve (AUC) were used to analyze the data.
RESULTS
One hundred and eighty-seven women with vasa previa were included. In this cohort, 79.6% (95% CI, 67.1-88.2%) of women classified as COS-1, 94.4% (95% CI, 84.9-98.1%) of those with gestational-sac implantation in the niche of the prior CS and 100% (95% CI, 93.4-100%) of those with gestational sac located below the uterine midline, on first-trimester ultrasound, were affected by the severest form of PAS disorder (PAS3) on third-trimester ultrasound. On multivariate logistic regression analysis, COS-1 (odds ratio (OR), 7.9 (95% CI, 4.0-15.5); P < 0.001), implantation of the gestational sac in the niche (OR, 29.1 (95% CI, 8.1-104); P < 0.001) and location of the gestational sac below the midline of the uterus (OR, 38.1 (95% CI, 12.0-121); P < 0.001) were associated independently with PAS3, whereas parity (P = 0.4) and the number of prior CDs (P = 0.5) were not. When translating these figures into diagnostic models, first-trimester diagnosis of COS-1 (AUC, 0.94 (95% CI, 0.91-0.97)), pregnancy implantation in the niche (AUC, 0.92 (95% CI, 0.89-0.96)) and gestational sac below the uterine midline (AUC, 0.92 (95% CI, 0.88-0.96)) had a high predictive accuracy for PAS3. There was an adverse surgical outcome in 22/187 pregnancies and it was more common in women with, compared to those without, COS-1 (P < 0.001), gestational-sac implantation in the niche (P < 0.001) and gestational-sac position below the uterine midline (P < 0.001). On multivariate logistic regression analysis, third-trimester ultrasound diagnosis of PAS3 (OR, 4.3 (95% CI, 2.1-17.3)) and first-trimester diagnosis of COS-1 (OR, 7.9 (95% CI, 4.0-15.5); P < 0.001), pregnancy implantation in the niche (OR, 29.1 (95% CI, 8.1-79.0); P < 0.001) and position of the sac below the uterine midline (OR, 6.6 (95% CI, 3.9-16.2); P < 0.001) were associated independently with adverse surgical outcome. When combining the sonographic coordinates of the three first-trimester imaging markers, we identified an area we call high-risk-for-PAS triangle, which may enable an easy visual perception and application of the three methods to prognosticate the risk for CS pregnancy and PAS disorder, although it requires validation in large prospective studies.
CONCLUSIONS
Early first-trimester sonographic assessment of pregnancies with previous CD can predict reliably ultrasound stage of PAS disorder. Combination of findings on first-trimester ultrasound with second- and third-trimester ultrasound examination can stratify the surgical risk in women affected by a PAS disorder. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
Topics: Adult; Cesarean Section; Cicatrix; Female; Humans; Obstetric Surgical Procedures; Placenta Accreta; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, First; Pregnancy Trimester, Third; Pregnancy, Ectopic; Prospective Studies; Retrospective Studies; Risk Assessment; Treatment Outcome; Ultrasonography, Prenatal
PubMed: 31788885
DOI: 10.1002/uog.21939 -
Clinical Case Reports Nov 2019Vasa previa is associated with high fetal morbidity and mortality rates. Although early diagnosis is important, rare types (non-type I and II) of vasa previa are...
Vasa previa is associated with high fetal morbidity and mortality rates. Although early diagnosis is important, rare types (non-type I and II) of vasa previa are diagnostically challenging. Our reconstructed images of the rare type of vasa previa are educational and could help clinicians to clinically diagnose this condition.
PubMed: 31788297
DOI: 10.1002/ccr3.2446