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American Journal of Obstetrics &... Aug 2020To systematically review published literature and calculate the prevalence of vasa previa and its known risk factors. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To systematically review published literature and calculate the prevalence of vasa previa and its known risk factors.
MATERIALS AND METHODS
MEDLINE, Embase, the Cochrane Library, PubMed (non-MEDLINE and in process), and www.clinicaltrials.gov were searched from inception to March 2018 using indexing terms "vasa previa," "placenta previa," "low lying placenta," "succenturiate lobe," "bilobate placenta," "bilobed placenta," and "velamentous insertion." All original research studies reporting on 5 or more pregnancies with vasa previa were included. The search was limited to studies on human data and those published in the English language. Two reviewers independently screened titles and abstracts, completed data extraction, and assessed reporting quality using the Study Quality Assessment Tool for Case Series Studies of the National Heart, Lung, and Blood Institute. Disagreements were discussed and resolved at each step of the process.
RESULTS
We included 21 studies that reported 428 pregnancies with vasa previa of 1,027,918 deliveries (0.46 cases of vasa previa per 1000 deliveries). These studies fared well on risk of bias assessment using the Study Quality Assessment Tool for Case Series Studies of the National Heart, Lung, and Blood Institute. The prevalence and 95% confidence intervals of known risk factors for vasa previa included a low-lying placenta (61.5%, 53.0%-70.0%), velamentous cord insertion (52.2%, 39.6%-64.7%), bilobed or succenturiate lobed placenta (33.3%, 20.9%-45.7%), use of in vitro fertilization (26.4%, 16.0%-36.8%), and multiple gestation (8.92%, 5.33%-12.5%).
CONCLUSION
Vasa previa affects 0.46 cases per 1000 pregnancies. Given the high prevalence of prenatally detectable risk factors in affected pregnancies, the cost-effectiveness of screening strategies for vasa previa either in isolation, using a risk factor-based approach, or universally, in tandem with cervical-length screening using transvaginal ultrasound, should be revisited.
Topics: Female; Humans; Placenta; Placenta Previa; Pregnancy; Risk Factors; Ultrasonography, Prenatal; Vasa Previa
PubMed: 33345868
DOI: 10.1016/j.ajogmf.2020.100117 -
Current Opinion in Obstetrics &... Dec 2018Vasa previa is a rare disorder of placentation associated with a high rate of perinatal morbidity and mortality when undetected before delivery. We have evaluated the...
PURPOSE OF REVIEW
Vasa previa is a rare disorder of placentation associated with a high rate of perinatal morbidity and mortality when undetected before delivery. We have evaluated the recent evidence for prenatal diagnosis and management of vasa previa.
RECENT FINDINGS
Around 85% of cases of vasa previa have one or more identifiable risk factors including in-vitro fertilization, multiple gestations, bilobed, succenturiate or low-lying placentas, and velamentous cord insertion. The development of standardized prenatal targeted scanning protocols may improve perinatal outcomes. There is no clear consensus on the optimal surveillance strategy including the need for hospitalization, timing of corticosteroids administration and the value of transvaginal cervical length measurements. Outpatient management is possible if there is no evidence of cervical shortening on ultrasound and there are no symptoms of bleeding or uterine contractions. Recent national guidelines and expert reviews have recommended scheduled cesarean section of all asymptomatic women presenting with vasa previa between 34 and 36 weeks' gestation.
SUMMARY
Prenatal diagnosis of vasa previa is pivotal to prevent intrapartum fetal death. Although there is insufficient evidence to support the universal mid-gestation ultrasound screening for vasa previa, recent evidence indicates the need for standardized prenatal targeted screening protocols of pregnancies at high-risk of vasa previa.
Topics: Adrenal Cortex Hormones; Adult; Cervical Length Measurement; Cesarean Section; Early Diagnosis; Female; Gestational Age; Humans; Practice Guidelines as Topic; Pregnancy; Pregnancy Complications; Prenatal Diagnosis; Risk Factors; Ultrasonography, Prenatal; Vasa Previa
PubMed: 30102606
DOI: 10.1097/GCO.0000000000000478 -
Biomedicines Dec 2022Vasa previa is a rare fetal life-threatening obstetric disease classified into types I and II. This study aimed to examine the characteristics and obstetric outcomes of... (Review)
Review
Vasa previa is a rare fetal life-threatening obstetric disease classified into types I and II. This study aimed to examine the characteristics and obstetric outcomes of type II vasa previa. A systematic review was performed, and 20 studies (1998-2022) were identified. The results from six studies showed that type II vasa previa accounted for 21.3% of vasa previa cases. The characteristics and obstetric outcomes (rate of assisted reproductive technology (ART), antenatal diagnosis, emergent cesarean delivery, maternal transfusion, gestational age at delivery, and neonatal mortality) were compared between type I and II vasa previa, and all outcomes of interest were similar. The association between ART and abnormal placenta (bilobed placenta or succenturiate lobe) was examined in three studies, and the results were as follows: () increased rate of succenturiate lobes (ART versus non-ART pregnancy; OR (odds ratio) 6.97, 95% confidence interval (CI) 2.45-19.78); () similar rate of abnormal placenta (cleavage-stage versus blastocyst embryo transfer); () increased rate of abnormal placenta (frozen versus fresh embryo transfer; OR 2.97, 95%CI 1.10-7.96). Although the outcomes of type II vasa previa appear to be similar to those of type I vasa previa, the current evidence is insufficient for a robust conclusion.
PubMed: 36552018
DOI: 10.3390/biomedicines10123263 -
Ultrasound in Obstetrics & Gynecology :... May 2015Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with... (Review)
Review
OBJECTIVE
Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with vasa previa, the risk of rupture of these vessels is increased, thus potentially causing fetal death or serious morbidity. Our objective was to assess the accuracy of ultrasound in the prenatal diagnosis of vasa previa.
METHODS
We searched MEDLINE, EMBASE, the Cochrane Library and PubMed for studies on vasa previa. Two reviewers independently selected studies on the accuracy of ultrasound in the diagnosis of vasa previa. The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). Data on sensitivity and specificity were subsequently extracted.
RESULTS
The literature search revealed 583 articles, of which two prospective and six retrospective cohort studies were eligible for inclusion in the qualitative analysis. All studies documented methods suitable for the prenatal diagnosis of vasa previa. Four out of the eight studies used transvaginal ultrasound (TVS) for primary evaluation, while the remaining four studies used transabdominal ultrasound and performed a subsequent TVS when vasa previa was suspected. The QUADAS-2 tool reflected poor methodology in six of the eight included studies, and prenatal detection rates varied from 53% (10/19) to 100% (total of 442,633 patients, including 138 cases of vasa previa). In the two prospective studies (n = 33,795, including 11 cases of vasa previa), transvaginal color Doppler performed during the second trimester detected all cases of vasa previa (sensitivity, 100%) with a specificity of 99.0-99.8%.
CONCLUSION
The accuracy of ultrasound in the diagnosis of vasa previa is high when performed transvaginally in combination with color Doppler.
Topics: Adult; Female; Humans; Placenta; Predictive Value of Tests; Pregnancy; Pregnancy Complications; Prospective Studies; Retrospective Studies; Ultrasonography, Doppler, Color; Ultrasonography, Prenatal; Umbilical Cord; Vasa Previa
PubMed: 25491755
DOI: 10.1002/uog.14752 -
Ultrasound in Obstetrics & Gynecology :... Jan 2024Type-III vasa previa (VP) is a rare form of VP, not necessarily associated with other placental or vascular anomalies, in which aberrant vessels run from the placenta to... (Review)
Review
OBJECTIVE
Type-III vasa previa (VP) is a rare form of VP, not necessarily associated with other placental or vascular anomalies, in which aberrant vessels run from the placenta to the amniotic membranes, near the internal cervical os, before returning to the placenta. Early diagnosis of Type-III VP is important but technically challenging. The objective of this study was to gather the current available evidence on the perinatal diagnosis and outcome of Type-III VP.
METHODS
A systematic review of the literature on the perinatal diagnosis of atypical Type-III VP was carried out in PubMed, MEDLINE and EMBASE accordingto PRISMA guidelines from inception to March 2023. Data extraction and tabulation were performed by two operators and checked by a third senior author. The quality of the included studies was evaluated using the National Institutes of Health tool for the quality assessment of case-series studies. Our local ultrasound database was searched for previously unreported recent cases. Characteristics of prenatally and postnatally diagnosed Type-III VP, including clinical features and perinatal outcomes, were summarized using descriptive statistics.
RESULTS
Eighteen cases of Type-III VP were included, of which 16 were diagnosed prenatally (14 cases were retrieved from 10 publications and two were unpublished cases from our center) and two were diagnosed postnatally (retrieved from two publications). All prenatal cases were diagnosed on transvaginal ultrasound at a mean gestational age of 29 weeks (median, 31 weeks; range, 19-38 weeks). Conception was achieved with in-vitro fertilization in 4/16 (25.0%) cases. There were no prenatal symptoms in 15/18 (83.3%) cases, while in two (11.1%) cases there was vaginal bleeding and in one (5.6%) preterm labor occurred. In 15/18 (83.3%) cases, at least one placental abnormality was observed, including low-lying insertion (9/17), succenturiate or accessory lobe (1/17), velamentous cord insertion (3/18) and marginal insertion (9/18). All prenatally diagnosed cases were liveborn and were delivered by Cesarean section before rupture of membranes at a median gestational age of 35 weeks (range, 32-38 weeks) without neonatal complications. Emergency Cesarean section was performed in 2/16 (12.5%) cases with a prenatal diagnosis and 1/2 (50.0%) cases with a postnatal diagnosis (P = 0.179). Among those with data available, an Apgar score of ≤ 7 was observed in the prenatally vs postnatally diagnosed group in 5/13 vs 1/1 cases, respectively, at the 1-min evaluation and 3/13 vs 1/1 cases, respectively, at the 5-min evaluation.
CONCLUSIONS
The prenatal diagnosis of Type-III VP is challenging, with few cases reported in the literature; however, it is crucial for minimizing the risk of adverse outcome by enabling early-term elective Cesarean delivery prior to rupture of membranes. Given that clinical manifestations and risk factors are non-specific, and that Type-III VP cannot be excluded when there is a normal cord insertion or a singular placental mass, systematic screening by transvaginal ultrasound in the general pregnant population is recommended, particularly in those with a low-lying or morphologically abnormal placenta and those who conceived using assisted reproductive technology. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Cesarean Section; Placenta; Placenta Diseases; Prenatal Diagnosis; Ultrasonography, Prenatal; Vasa Previa
PubMed: 37470694
DOI: 10.1002/uog.26315 -
BMJ Open Sep 2023To derive accurate estimates of the incidence of vasa praevia (VP) in a routine population of unselected pregnancies. (Meta-Analysis)
Meta-Analysis
OBJECTIVES
To derive accurate estimates of the incidence of vasa praevia (VP) in a routine population of unselected pregnancies.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
A search of MEDLINE, EMBASE, CINAHL and the Cochrane database was performed to review relevant citations reporting outcomes in pregnancies with VP from January 2000 until 5 April 2023.
ELIGIBILITY CRITERIA FOR SELECTION OF STUDIES
Prospective or retrospective cohort or population studies that provided data regarding VP cases in routine unselected pregnancies during the study period. We included studies published in the English language after the year 2000 to reflect contemporary obstetric and neonatal practice.
DATA EXTRACTION AND SYNTHESIS
Two reviewers independently screened the retrieved citations and extracted data. The methodological quality of studies was assessed using the Newcastle-Ottawa Scale, and Preferred Reporting Items for Systematic reviews and Meta-Analyses was used to ensure standardised reporting of studies.
RESULTS
A total of 3847 citations were screened and 82 full-text manuscripts were retrieved for analysis. There were 24 studies that met the inclusion criteria, of which 12 studies reported prenatal diagnosis with a systematic protocol of screening. There were 1320 pregnancies with VP in a total population of 2 278 561 pregnancies; the weighted pooled incidence of VP was 0.79 (95% CI: 0.59 to 1.01) per 1000 pregnancies, corresponding to 1 case of VP per 1271 (95% CI: 990 to 1692) pregnancies. Nested subanalysis of studies reporting screening for VP based on a specific protocol identified 395 pregnancies with VP in a population of 732 654 pregnancies with weighted pooled incidence of 0.82 (95% CI: 0.53 to 1.18) per 1000 pregnancies (1 case of VP per 1218 (95% CI: 847 to 1901) pregnancies).
CONCLUSION
The incidence of VP in unselected pregnancies is 1 in 1218 pregnancies. This is higher than is previously reported and can be used as a basis to assess whether screening for this condition should be part of routine clinical practice. Incorporation of strategies to screen for VP in routine clinical practice is likely to prevent 5% of stillbirths.
PROSPERO REGISTRATION NUMBER
CRD42020125495.
Topics: Infant, Newborn; Female; Pregnancy; Humans; Incidence; Prospective Studies; Retrospective Studies; Vasa Previa; Databases, Factual
PubMed: 37730391
DOI: 10.1136/bmjopen-2023-075245 -
Biomedicines Jul 2022Abnormal cord insertion (ACI) is associated with adverse obstetric outcomes; however, the relationship between ACI and assisted reproductive technology (ART) has not... (Review)
Review
Abnormal cord insertion (ACI) is associated with adverse obstetric outcomes; however, the relationship between ACI and assisted reproductive technology (ART) has not been examined in a meta-analysis. This study examines the association between ACI and ART, and delivery outcomes of women with ACI. A systematic review was conducted, and 16 studies (1990-2021) met the inclusion criteria. In the unadjusted pooled analysis ( = 10), ART was correlated with a higher rate of velamentous cord insertion (VCI) (odds ratio (OR) 2.14, 95% confidence interval (CI) 1.64-2.79), marginal cord insertion ( = 6; OR 1.58, 95%CI 1.26-1.99), and vasa previa ( = 1; OR 10.96, 95%CI 2.94-40.89). Nevertheless, the VCI rate was similar among the different ART types (blastocyst cleavage-stage transfer and frozen fresh embryo transfer). Regarding the cesarean delivery (CD) rate, women with VCI were more likely to have elective ( = 3; OR 1.13, 95%CI 1.04-1.22) and emergent CD ( = 5; OR 1.93, 95%CI 1.82-2.03). In conclusion, ART may be correlated with an increased prevalence of ACI. However, most studies could not exclude confounding factors; thus, further studies are warranted to characterize ART as a risk factor for ACI. In women with ACI, elective and emergent CD rates are high.
PubMed: 35885027
DOI: 10.3390/biomedicines10071722 -
American Journal of Obstetrics and... Jan 2024This study aimed to estimate the perinatal mortality associated with prenatally diagnosed vasa previa and to determine what proportion of those perinatal deaths are... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
This study aimed to estimate the perinatal mortality associated with prenatally diagnosed vasa previa and to determine what proportion of those perinatal deaths are directly attributable to vasa previa.
DATA SOURCES
The following databases have been searched from January 1, 1987, to January 1, 2023: PubMed, Scopus, Web of Science, and Embase.
STUDY ELIGIBILITY CRITERIA
Our study included all studies (cohort studies and case series or reports) that had patients in which a prenatal diagnosis of vasa previa was made. Case series or reports were excluded from the meta-analysis. All cases in which prenatal diagnosis was not made were excluded from the study.
METHODS
The programming language software R (version 4.2.2) was used to conduct the meta-analysis. The data were logit transformed and pooled using the fixed effects model. The between-study heterogeneity was reported by I. The publication bias was evaluated using a funnel plot and the Peters regression test. The Newcastle-Ottawa scale was used to assess the risk of bias.
RESULTS
Overall, 113 studies with a cumulative sample size of 1297 pregnant individuals were included. This study included 25 cohort studies with 1167 pregnancies and 88 case series or reports with 130 pregnancies. Moreover, 13 perinatal deaths occurred among these pregnancies, consisting of 2 stillbirths and 11 neonatal deaths. Among the cohort studies, the overall perinatal mortality was 0.94% (95% confidence interval, 0.52-1.70; I=0.0%). The pooled perinatal mortality attributed to vasa previa was 0.51% (95% confidence interval, 0.23-1.14; I=0.0%). Stillbirth and neonatal death were reported in 0.20% (95% confidence interval, 0.05-0.80; I=0.0%) and 0.77% (95% confidence interval, 0.40-1.48; I=0.0%) of pregnancies, respectively.
CONCLUSION
Perinatal death is uncommon after a prenatal diagnosis of vasa previa. Approximately half of the cases of perinatal mortality are not directly attributable to vasa previa. This information will help in guiding physicians in counseling and will provide reassurance to pregnant individuals with a prenatal diagnosis of vasa previa.
Topics: Pregnancy; Infant, Newborn; Female; Humans; Vasa Previa; Perinatal Death; Incidence; Prenatal Diagnosis; Stillbirth; Ultrasonography, Prenatal
PubMed: 37321285
DOI: 10.1016/j.ajog.2023.06.015 -
American Journal of Obstetrics &... Aug 2020To evaluate reported outcomes of published studies on the diagnosis and management of vasa previa in pregnancy. (Review)
Review
OBJECTIVE
To evaluate reported outcomes of published studies on the diagnosis and management of vasa previa in pregnancy.
MATERIALS AND METHODS
Databases such as MEDLINE, Embase, Cochrane, PubMed, and ClinicalTrials.gov were searched up to March 2018 for all published studies on vasa previa using combinations of the following medical subject headings and key words: vasa previa, placenta previa, low-lying placenta, succenturiate lobe or placenta, bilobed or bilobate placenta, and velamentous insertion. All original human research that described maternal, obstetric, placental, fetal or neonatal outcomes relating to pregnancies with vasa previa were included for analysis. Title and abstract screening and data extraction was conducted independently and in duplicate by 2 reviewers for all studies until total agreement for eligibility was achieved. Data extraction was also conducted in duplicate in approximately 50% of studies reviewed.
RESULTS
A total of 160 published studies (1004 pregnancies) were included. There was a wide range of reported outcomes, many of which were sparingly reported. The most commonly reported maternal outcomes included mode of delivery, presence of antepartum hemorrhage, time of diagnosis, and rupture of membranes. The presence of known risk factors for vasa previa such as a low-lying placenta, succenturiate or bilobed placenta, and (velamentous) cord insertion was incorrectly reported as "outcomes" in many studies. The most commonly reported fetal/neonatal outcomes included fetal heart rate, gestational age at delivery, birthweight, Apgar score, presence of neonatal anemia, cord blood gas measurements, need for blood transfusion, and death. Of note, only 3 studies reported outcomes related to life impact, maternal social and emotional functioning, perceived delivery of care, or resource utilization.
CONCLUSION
Despite the profound effect the diagnosis of vasa previa has on pregnant women, families, and healthcare systems, studies on vasa previa seldom report outcomes related to life impact and resource utilization. There is a need for the development of a core outcome set-a minimum standard set of outcomes deemed important by pregnant women and other stakeholders involved in their care-to standardize outcome reporting in future studies on vasa previa.
Topics: Female; Gestational Age; Humans; Infant, Newborn; Patient Reported Outcome Measures; Placenta; Placenta Previa; Pregnancy; Vasa Previa
PubMed: 33345867
DOI: 10.1016/j.ajogmf.2020.100116 -
Obstetrics and Gynecology Sep 2023To determine the causes and potential preventability of perinatal deaths in prenatally identified cases of vasa previa.
OBJECTIVE
To determine the causes and potential preventability of perinatal deaths in prenatally identified cases of vasa previa.
DATA SOURCES
Reports of prenatally identified cases of vasa previa published in the English language literature since 2000 were identified in Medline and ClinicalTrials.gov with the search terms "vasa previa," "abnormal cord insertion," "velamentous cord," "marginal cord," "bilobed placenta," and "succenturiate lobe."
METHODS OF STUDY SELECTION
All cases from the above search with an antenatally diagnosed vasa previa present at delivery in singleton or twin gestations with perinatal mortality information were included.
TABULATION, INTEGRATION, AND RESULTS
Cases meeting inclusion criteria were manually abstracted, and multiple antenatal, intrapartum, and outcome variables were recorded. Deaths and cases requiring neonatal transfusion were analyzed in relation to plurality, routine hospitalization, and cervical length monitoring. A total of 1,109 prenatally diagnosed cases (1,000 singletons, 109 twins) were identified with a perinatal mortality rate attributable to vasa previa of 1.1% (95% CI 0.6-1.9%). All perinatal deaths occurred with unscheduled deliveries. The perinatal mortality rate in twin pregnancies was markedly higher than that in singleton pregnancies (9.2% vs 0.2%, P <.001), accounting for 80% of overall mortality despite encompassing only 9.8% of births. Compared with individuals with singleton pregnancies, those with twin pregnancies are more likely to undergo unscheduled delivery (56.4% vs 35.1%, P =.01) despite delivering 2 weeks earlier (33.2 weeks vs 35.1 weeks, P =.006). An institutional policy of routine hospitalization is associated with a reduced need for neonatal transfusion (0.9% vs 6.0%, P <.001) and a reduction in the perinatal mortality rate in twin pregnancies (0% vs 25%, P =.002) but not in singleton pregnancies (0% vs 0.5%, P =.31).
CONCLUSION
Routine hospitalization and earlier delivery of twins may result in a reduction in the perinatal mortality rate. A smaller benefit from routine admission of individuals with singleton pregnancies cannot be excluded. There is currently insufficient evidence to recommend the routine use of cervical length measurements to guide clinical management.
Topics: Infant, Newborn; Pregnancy; Female; Humans; Vasa Previa; Perinatal Death; Perinatal Mortality; Retrospective Studies; Prenatal Diagnosis; Pregnancy, Twin; Ultrasonography, Prenatal
PubMed: 37535966
DOI: 10.1097/AOG.0000000000005296