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American Journal of Obstetrics and... Aug 2022The ideal time for birth in pregnancies diagnosed with vasa previa remains unclear. We conducted a systematic review aiming to identify the gestational age at delivery... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
The ideal time for birth in pregnancies diagnosed with vasa previa remains unclear. We conducted a systematic review aiming to identify the gestational age at delivery that best balances the risks for prematurity with that of pregnancy prolongation in cases with prenatally diagnosed vasa previa.
DATA SOURCES
Ovid MEDLINE, PubMed, CINAHL, Embase, Scopus, and Web of Science were searched from inception to January 2022.
STUDY ELIGIBILITY CRITERIA
The intervention analyzed was delivery at various gestational ages in pregnancies prenatally diagnosed with vasa previa. Cohort studies, case series, and case reports were included in the qualitative synthesis. When summary figures could not be obtained directly from the studies for the quantitative synthesis, authors were contacted and asked to provide a breakdown of perinatal outcomes by gestational age at birth.
METHODS
Study appraisal was completed using the National Institutes of Health quality assessment tool for the respective study types. Statistical analysis was performed using a random-effects meta-analysis of proportions.
RESULTS
The search identified 3435 studies of which 1264 were duplicates. After screening 2171 titles and abstracts, 140 studies proceeded to the full-text screen. A total of 37 studies were included for analysis, 14 of which were included in a quantitative synthesis. Among 490 neonates, there were 2 perinatal deaths (0.4%), both of which were neonatal deaths before 32 weeks' gestation. In general, the rate of neonatal complications decreased steadily from <32 weeks' gestation (4.6% rate of perinatal death, 91.2% respiratory distress, 11.4% 5-minute Apgar score <7, 23.3% neonatal blood transfusion, 100% neonatal intensive care unit admission, and 100% low birthweight) to 36 weeks' gestation (0% perinatal death, 5.3% respiratory distress, 0% 5-minute Apgar score <7, 2.9% neonatal blood transfusion, 29.2% neonatal intensive care unit admission, and 30.9% low birthweight). Complications then increased slightly at 37 weeks' gestation before decreasing again at 38 weeks' gestation.
CONCLUSION
Prolonging pregnancies until 36 weeks' gestation seems to be safe and beneficial in otherwise uncomplicated pregnancies with antenatally diagnosed vasa previa.
Topics: Birth Weight; Female; Gestational Age; Humans; Infant, Newborn; Perinatal Death; Pregnancy; Pregnancy Outcome; Respiratory Distress Syndrome; Vasa Previa
PubMed: 35283090
DOI: 10.1016/j.ajog.2022.03.006 -
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 -
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 -
Ultrasound in Obstetrics & Gynecology :... May 2021To derive accurate estimates of perinatal survival in pregnancies with and without a prenatal diagnosis of vasa previa based on a systematic review of the literature and... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
To derive accurate estimates of perinatal survival in pregnancies with and without a prenatal diagnosis of vasa previa based on a systematic review of the literature and meta-analysis.
METHODS
A search of MEDLINE, EMBASE and The Cochrane Library was performed to review relevant citations reporting on the perinatal outcomes of pregnancies with vasa previa. We included prospective and retrospective cohort and population studies that provided data on pregnancies with a prenatal diagnosis of vasa previa or cases diagnosed at birth or following postnatal placental examination. Meta-analysis using a random-effects model was performed to derive weighted pooled estimates of perinatal survival (excluding stillbirths and neonatal deaths) and intact perinatal survival (additionally excluding hypoxic morbidity). Incidence rate difference (IRD) meta-analysis was used to estimate the significance of differences in pooled proportions between cases of vasa previa with and those without a prenatal diagnosis. Heterogeneity between studies was estimated using Cochran's Q and the I statistic.
RESULTS
We included 21 studies reporting on the perinatal outcomes of 683 pregnancies with a prenatal diagnosis of vasa previa. There were three stillbirths (1.01% (95% CI, 0.40-1.87%)), five neonatal deaths (1.19% (95% CI, 0.52-2.12%)) and 675 surviving neonates, resulting in a pooled estimate for perinatal survival of 98.6% (95% CI, 97.6-99.3%). Based on seven studies that included cases of vasa previa with and without a prenatal diagnosis, the pooled perinatal survival in pregnancies without a prenatal diagnosis (61/118) was 72.1% (95% CI, 50.6-89.4%) vs 98.6% (95% CI, 96.7-99.7%) in cases with a prenatal diagnosis (224/226). Therefore, the risk of perinatal death was 25-fold higher when a diagnosis of vasa previa was not made antenatally, compared with when it was (odds ratio (OR), 25.39 (95% CI, 7.93-81.31); P < 0.0001). Similarly, the risk of hypoxic morbidity was increased 50-fold in cases with vasa previa without a prenatal diagnosis compared with those with a prenatal diagnosis (36/61 vs 5/224; OR, 50.09 (95% CI, 17.33-144.79)). The intact perinatal survival rate in cases of vasa previa without a prenatal diagnosis was significantly lower than in those with a prenatal diagnosis (28.1% (95% CI, 14.1-44.7%) vs 96.7% (95% CI, 93.6-98.8%)) (IRD, 73.4% (95% CI, 53.9-92.7%); Z = -7.4066, P < 0.001).
CONCLUSIONS
Prenatal diagnosis of vasa previa is associated with a high rate of perinatal survival, whereas lack of an antenatal diagnosis significantly increases the risk of perinatal death and hypoxic morbidity. Further research should be undertaken to investigate strategies for incorporating prenatal screening for vasa previa into routine clinical practice. © 2020 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; Perinatal Mortality; Pregnancy; Pregnancy Outcome; Prenatal Diagnosis; Prospective Studies; Retrospective Studies; Vasa Previa
PubMed: 32735754
DOI: 10.1002/uog.22166 -
British Journal of Sports Medicine Dec 2020Clinical guidelines recommend pregnant women without contraindication engage in regular physical activity. This is based on extensive evidence demonstrating the safety...
BACKGROUND
Clinical guidelines recommend pregnant women without contraindication engage in regular physical activity. This is based on extensive evidence demonstrating the safety and benefits of prenatal exercise. However, certain medical conditions or contraindications warrant a reduction, modification or cessation of activity due to potential health risks.
AIM
To review and evaluate the evidence related to medical disorders which may warrant contraindication to prenatal exercise.
METHODS
Online databases were searched up to 5 April 2019. Forty-four unique studies that reported data on our Population (pregnant women with contraindication to exercise), Intervention (subjective/objective measures of acute or chronic exercise), Comparator (not essential) and Outcomes (adverse maternal or fetal outcomes) were included in the review.
KEY FINDINGS
We found that the majority of medical conditions listed as contraindications were based on expert opinion; there is minimal empirical evidence to demonstrate harm of exercise and benefit of activity restriction. We identified 11 complications (eg, gestational hypertension, twin pregnancy) previously classified as contraindications where women may in fact benefit from regular prenatal physical activity with or without modifications. However, the evidence suggests that severe cardiorespiratory disease, placental abruption, vasa previa, uncontrolled type 1 diabetes, intrauterine growth restriction, active preterm labour, severe pre-eclampsia and cervical insufficiency are associated with strong potential for maternal/fetal harm and warrant classification as absolute contraindications.
CONCLUSION
Based on empirical evidence, we provide a call to re-evaluate clinical guidelines related to medical disorders that have previously been considered contraindications to prenatal exercise. Removing barriers to physical activity during pregnancy for women with certain medical conditions may in fact be beneficial for maternal-fetal health outcomes.
Topics: Contraindications; Exercise; Female; Humans; Practice Guidelines as Topic; Pregnancy; Pregnancy Complications; Prenatal Care
PubMed: 32513676
DOI: 10.1136/bjsports-2020-102042 -
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 -
American Journal of Obstetrics and... Jun 2017Twin pregnancies are at higher risks of velamentous cord insertion and vasa previa. In vitro fertilization is an additional risk factor of abnormal cord insertion and... (Review)
Review
BACKGROUND
Twin pregnancies are at higher risks of velamentous cord insertion and vasa previa. In vitro fertilization is an additional risk factor of abnormal cord insertion and thus the incidence of vasa previa is likely to increase over the next decades.
OBJECTIVE
We sought to evaluate the role of ultrasound imaging in optimizing the management of twins diagnosed with vasa previa antenatally.
STUDY DESIGN
We searched our database for twin pregnancies diagnosed with vasa previa and managed antenatally using measurements of cervical length and performed a systematic review of articles that correlated prenatal diagnosis of vasa previa in twins and pregnancy outcome. PubMed and MEDLINE were searched for studies published from 1987 through October 20, 2016, using specific medical subject heading terms, key words, and their combination. The primary eligibility criteria were articles that correlated prenatal ultrasound imaging of vasa previa and pregnancy outcome in twins. The secondary eligibility criteria was the use of cervical length in the management of twin pregnancies diagnosed antenatally with vasa previa. Two authors independently assessed inclusion criteria, data extraction, and analysis. The final selection included 3 case report series, 9 retrospective cohort studies, and 1 retrospective case-control study of vasa previa diagnosed prenatally and confirmed at birth in twin pregnancies.
RESULTS
The search of our databases identified 6 cases of dichorionic-diamniotic twins and 1 case of monochorionic-diamniotic twins diagnosed prenatally with vasa previa between 22-29 weeks and managed using cervical length. Two cases were delivered by emergency because of rapid changes in cervical length in one and bleeding on placenta previa in the other at 33 and 30 weeks, respectively. The systematic review identified data on 56 cases. The incidence of twin pregnancies diagnosed antenatally with vasa previa in the cohort and case-control studies was 11.0%. Data on chorionicity were available in only 34 cases and cervical length measurements were used by only the authors of 2 case reports and 4 cohort studies. Velamentous cord insertion was the most common additional ultrasound findings in twins presenting with vasa previa in both our series and the systematic review.
CONCLUSION
Vasa previa is associated with specific prenatal and obstetric complications with different outcomes in singletons compared to twins. Data on the diagnosis and management of vasa previa in twin pregnancies are limited but there is enough evidence to warrant guidelines for targeted screening. To enable the development of efficient management protocols tailored to the need of individual cases, future studies of the screening, diagnosis, and management of vasa previa should be prospective and multicentric with detailed data on twins including chorionicity and use of cervical length.
Topics: Case-Control Studies; Cervix Uteri; Chorion; Cohort Studies; Diseases in Twins; Female; Gestational Age; Humans; MEDLINE; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy, Twin; Prenatal Diagnosis; Retrospective Studies; Ultrasonography, Prenatal; Vasa Previa
PubMed: 28153653
DOI: 10.1016/j.ajog.2017.01.029 -
BJOG : An International Journal of... Jul 2016Vasa praevia (VP) is a rare phenomenon that is assumed to increase the risk of severe complications, including fetal death. Critical data on its incidence are lacking,... (Review)
Review
BACKGROUND
Vasa praevia (VP) is a rare phenomenon that is assumed to increase the risk of severe complications, including fetal death. Critical data on its incidence are lacking, so there is no rational basis for prenatal screening.
OBJECTIVES
To review the literature on the incidence and risk indicators for VP.
SEARCH STRATEGY
We searched OVID MEDLINE, OVID EMBASE, the Cochrane Library and PubMed for case-control and cohort studies on incidence and risk indicators for VP.
SELECTION CRITERIA
Two reviewers selected studies and scored their methodological quality.
DATA COLLECTION AND ANALYSIS
We calculated the mean incidence of VP. We constructed 2 × 2 tables cross-classifying potential risk indicators against the incidence of VP to calculate common odds ratios and 95% confidence intervals, using the Mantel-Haenszel method.
MAIN RESULTS
We included 13 studies (two prospective cohort studies, ten retrospective cohort studies and one case-control study) reporting on 569 410 patients with 325 cases of VP. Based on ten included cohort studies providing information on the incidence, the mean incidence of VP was 0.60 per 1000 pregnancies. We identified five different risk indicators and markers for VP: second-trimester placenta praevia, conception by assisted reproductive technologies, a bilobed or succenturiate placenta, umbilical cord insertion in the lower third part of the uterus at first-trimester ultrasound and velamentous cord insertion. Almost 83% of the cases of VP had one or more risk indicators.
AUTHORS' CONCLUSIONS
In view of the low incidence, screening for VP in an unselected population is not advised. Targeted screening of women with one or more risk indicators as a part of routine mid-gestation scanning should be considered.
TWEETABLE ABSTRACT
Vasa praevia is more common in placenta praevia, conception by ART, velamentous cord insertion and bilobed placenta.
Topics: Female; Humans; Odds Ratio; Placenta; Placenta Previa; Pregnancy; Pregnancy Trimester, First; Pregnancy Trimester, Second; Reproductive Techniques, Assisted; Risk; Risk Assessment; Ultrasonography, Prenatal; Umbilical Cord; Vasa Previa
PubMed: 26694639
DOI: 10.1111/1471-0528.13829 -
American Journal of Obstetrics and... Oct 2015We sought to evaluate the extent of the association between placental implantation abnormalities (PIA) and preterm delivery in singleton gestations. We conducted a... (Meta-Analysis)
Meta-Analysis Review
We sought to evaluate the extent of the association between placental implantation abnormalities (PIA) and preterm delivery in singleton gestations. We conducted a systematic review of English-language articles published from 1980 onward using PubMed, MEDLINE, EMBASE, CINAHL, LILACS, and Google Scholar, and by identifying studies cited in the references of published articles. Search terms were PIA defined as ≥ 1 of the following: placenta previa, placenta accreta, vasa previa, and velamentous cord insertion. Observational and experimental studies were included for review if data were available regarding any of the aforementioned PIA and regarding gestational age at delivery or preterm delivery. Case reports and case series were excluded. Studies were reviewed and data extracted. The primary outcome was gestational age at delivery or preterm delivery <37 weeks' gestation. Secondary outcomes included birthweight, 1- and 5-minute Apgar scores, neonatal intensive care unit (NICU) admission, neonatal and perinatal death, and small for gestational age. Of the 1421 studies identified, 79 met the defined criteria; 56 studies were descriptive and 23 were comparative. Based on the descriptive studies, the preterm delivery rates for low-lying/marginal placenta, placenta previa, placenta accreta, vasa previa, and velamentous cord insertion were 26.9%, 43.5%, 57.7%, 81.9%, and 37.5%, respectively. Based on the comparative studies using controls, there was decreased pregnancy duration for every PIA; more specifically, there was an increased risk for preterm delivery in patients with placenta previa (risk ratio [RR], 5.32; 95% confidence interval [CI], 4.39-6.45), vasa previa (RR, 3.36; 95% CI, 2.76-4.09), and velamentous cord insertion (RR, 1.95; 95% CI, 1.67-2.28). Risks of NICU admissions (RR, 4.09; 95% CI, 2.80-5.97), neonatal death (RR, 5.44; 95% CI, 3.03-9.78), and perinatal death (RR, 3.01; 95% CI, 1.41-6.43) were higher with placenta previa. Perinatal risks were also higher in patients with vasa previa (perinatal death rate RR, 4.52; 95% CI, 2.77-7.39) and velamentous cord insertion (NICU admissions [RR, 1.76; 95% CI, 1.68-1.84], small for gestational age [RR, 1.69; 95% CI, 1.56-1.82], and perinatal death [RR, 2.15; 95% CI, 1.84-2.52]). In singleton gestations, there is a strong association between PIA and preterm delivery resulting in significant perinatal morbidity and mortality.
Topics: Apgar Score; Birth Weight; Female; Gestational Age; Humans; Infant, Newborn; Infant, Small for Gestational Age; Intensive Care, Neonatal; Perinatal Death; Placenta Accreta; Placenta Diseases; Placenta Previa; Pregnancy; Premature Birth; Risk Factors; Vasa Previa
PubMed: 26428506
DOI: 10.1016/j.ajog.2015.05.058 -
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