Prenatal Diagnosis Of Vasa Previa Research Articles

Diagnosis and Analysis of Vasa Previa Types With Flow HD Glass Body.

To explore the value of applying flow high definition (HD) glass body in prenatal diagnosis of vasa previa and to preliminarily discuss the types of vasa previa. Two-dimensional ultrasound, flow HD, and flow HD glass body were used to image the umbilical cord insertion site and placenta, observe the cervical internal os and surrounding areas, and retrospectively analyze cases of vasa previa. There were 15 cases of vasa previa, including 14 cases of singleton pregnancies and 1 case of twin pregnancy, with a total of 22 vasa previa, including 10 veins and 12 arteries. There was 1 case with 3 vessels, 5 cases with 2 vessels, and 9 cases with a single vessel. Among them, in 3 cases of vasa previa detected at 12, 14, and 24 weeks, respectively, the vasa previa were relocated to a normal position at 24, 29, and 35 weeks of gestation when re-examined. Routine 2-dimensional ultrasound examination in this group showed tubular or circular hypoechoic areas near the cervical internal os, but vasa previa could not be confirmed. Flow HD could display color blood flow at and near the cervical internal os in 15 cases, but it was difficult to continuously show the course and source of the blood vessels under the chorion. Flow HD glass body from multiple angles could display the relationship between 15 cases of 22 vasa previa and the placenta and cervix. Combined with color Doppler blood flow spectra, flow HD glass body could determine the types of vasa previa. Flow HD glass body imaging can clearly display vasa previa, showing their origin and the spatial relationship with the cervix and placenta in a 3-dimensional manner, displaying the course and attachment points of umbilical vessels under the chorion. It can observe the area of interest at any angle, and combined with color Doppler blood flow spectra, it can judge the vasa previa of the umbilical vein, providing a more definite imaging basis for clinical management.

Perinatal Mortality Despite Prenatal Diagnosis of Vasa Previa: A Systematic Review.

To determine the causes and potential preventability of perinatal deaths in prenatally identified cases of vasa previa. 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." 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. 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). 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.

The association of gestational age at delivery with neonatal outcomes in prenatally diagnosed vasa previa

Objective To report on the association of gestational age at delivery and neonatal outcomes in prenatally diagnosed vasa previa. Methods A retrospective cohort study at two academic/community hybrid hospitals, covered by the same maternal-fetal medicine group. Neonatal characteristics and outcomes were compared between cases of prenatally diagnosed vasa previa delivered at gestational age <36 weeks and ≥36 weeks. Results We identified 59 cases of vasa previa, of which 2 were excluded, one due to delivery at 28 weeks for preeclampsia, and one because it was not diagnosed prenatally, leaving 57 pregnancies in our study. There were 2 sets of twins. As such, there were 59 newborns. The mean gestational age at delivery was 35.08 (± 0.27) weeks for those delivered at <36 weeks, and 36.11 (±0.16) weeks for those delivered ≥36 weeks. All cases were delivered by cesarean. Delivery at ≥36 weeks was associated with greater mean birth weight (2774 g (±376.3 g)) compared with 2292.5 g (± 406.8 g) for those babies delivered at <36 weeks (p < 0.001). In addition, there were shorter hospital stays for the babies delivered at ≥36 weeks (median 3 days; interquartile range (IQR) 3,3) when compared with those delivered at <36 weeks (median 13 days; IQR 3,20). In addition, delivery at ≥36 weeks was associated with lower rates of intubation, jaundice and respiratory distress syndrome. Importantly, no cases of rupture of the membranes or vessel rupture occurred in either group. Conclusion Our study suggests that delivery at ≥36 weeks is safe for asymptomatic patients with prenatally diagnosed vasa previa, and may be associated with improved neonatal outcomes. We suggest that stable asymptomatic patients with prenatal diagnosis of vasa previa be delivered at 36 weeks rather than at less than 36 weeks. This will reduce neonatal morbidity with no apparent increased risk to babies.

Perinatal Outcome of Pregnancies With Prenatal Diagnosis of Vasa Previa: Systematic Review and Meta-analysis

(Abstracted from Ultrasound Obstet Gynecol 2021;57:710–719) Pregnancies with vasa previa are at risk for fetal death and hypovolemic shock due fetal blood loss. Several studies have shown that prenatal diagnosis of vasa previa improves the rate of live births.

Perinatal outcome of pregnancies with prenatal diagnosis of vasa previa: systematic review and meta-analysis.

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. 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 I2 statistic. 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). 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.

A survey of opinion and practice regarding prenatal diagnosis of vasa previa among obstetricians from Australia and New Zealand.

To define current obstetric opinion and clinical practice regarding the prenatal diagnosis of vasa previa in Australia and New Zealand. A population-based cross-sectional survey of Fellows of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists was conducted from April to May, 2016. Descriptive analysis was used to define factors influencing opinion and practice regarding definition of vasa previa, attributable risk factors, and the value of screening. Overall, 453 respondents were included in the study. Two-thirds (304/453; 67.1%) defined vasa previa as exposed fetal vessel(s) running over or within 2cm of the internal os. A higher proportion of ultrasound specialists (30/65; 46.2%) preferred a broader definition as compared with generalists (115/388; 29.6%; P<0.001). Overall, Fellows were supportive (342/430; 79.5%) of both reporting ultrasound-based risk factors at the 20-week anomaly scan and targeted screening (298/430; 69.3%). Only 77/453 (17.0%) respondents recognized all five "known" risk factors for vasa previa. There was a lack of consensus regarding the definition and diagnosis process for vasa previa. There was also a knowledge gap in risk factors for vasa previa that would inform a targeted screening policy. Nevertheless, support for targeted screening was strong from obstetricians who responded.

734: Prevalence of obstetric risk factors in pregnancies with vasa previa: A systematic review and meta- analysis

To review existing literature and calculate the prevalence of vasa previa and its known risk factors in affected pregnancies. We conducted a systematic review of observational studies in accordance with the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Five databases, Medline, Embase, the Cochrane Library, PubMed and www.clinicaltrials.gov were searched and only studies describing more than five cases of vasa previa were included. Two reviewers independently carried out title and abstract screening and data extraction from included full-texts. Disagreements were resolved through discussion. The references of included papers were screened to identify articles missed by the initial literature search. We performed DerSimonian-Laird binary random- effects meta-analyses using OpenMetaAnalyst, presenting pooled proportions with 95% confidence intervals (CI), of the prevalence of risk factors in cases of vasa previa. We included 22 studies that reported 447 pregnancies with vasa previa out of 1,121,792 deliveries (0.43 cases of vasa previa per 1000 deliveries). The prevalence of known risk factors for vasa previa included a low-lying placenta [61.5% (53.0-70.0%)], velamentous cord insertion [52.7% (41.1-64.3%)], bilobed or succenturiate lobed placenta [32.7% (21.1-44.3%)], the use of any assisted reproductive technique [28.2% (20.1-36.3%)] (including in-vitro fertilization [26.4% (16.0-36.8%]), and multiple gestation [9.10% (5.6-12.6%)]. These studies fared well on risk of bias assessment. Although prenatal diagnosis of vasa previa has been shown to improve obstetrical and neonatal outcomes with a prevalence of 0.43 per 100 pregnancies, population-based screening may not be cost-effective. However, a policy of screening pregnancies at increased risk for vasa previa may be a reasonable option, the clinical and cost-effectiveness of which needs to be determined.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

193: Prenatal diagnosis of vasa previa: Outpatient versus inpatient management

The optimal antenatal management and the timing of delivery in women with prenatal diagnosis of vasa previa have not been established. The aim of this study was to compare pregnancy outcome of two different management strategies (outpatient versus inpatient) and a policy of elective cesarean section at 36 weeks of gestation in pregnancies complicated with vasa previa This was a retrospective cohort study conducted at a single tertiary center. All women with a prenatally diagnosed vasa previa between 01/2007-05/2017 were included. Vasa previa was confirmed by serial ultrasound examinations and placental examination. Obstetric and neonatal outcomes were compared between two management strategies: elective admission at 34.0 weeks of gestation or outpatient management unless there were signs of labor or premature contractions. All women had a planned cesarean delivery at 36 weeks. 109 women met inclusion criteria: 75 (68.8%) women in the inpatient group and 34 (31.2%) in the outpatient group. Women in the inpatient group were admitted earlier (34.0 vs 35.3 weeks, respectively, P=0.002) and were more likely to be delivered earlier (36.0 vs 36.2 weeks, respectively, P=0.01) compared to outpatient group. Women in the inpatient group were more likely to receive antenatal steroids (57.3% vs 23.5%, respectively, P=0.002), but less likely to have an urgent cesarean section (18.9% vs 58.8%, respectively, P<0.001). However, the rate of cesarean before 36 weeks of gestation was similar between the two groups (34.7% vs 31.6%, respectively, P=0.8) and there was no significant difference in the rate of operative complications (18.9% vs 14.7%, respectively P=0.65) or post-partum complications (12.0% vs 26.5%, P= 0.09) between the groups. There was no difference in the rate of neonatal complications (inpatient: 68.9% vs outpatient: 57.5%, P=0.255) or neonatal anemia requiring transfusion (2.7% vs 5.8%, respectively, P=0.5) between the groups. There was one case of neonatal death due to severe intrauterine growth restriction. A policy of planned cesarean delivery at 36 weeks of gestation in cases with prenatally diagnosed vasa previa is safe, however, it is prudent to recommend elective inpatient hospitalization at 34 weeks of gestation as the rate of urgent cesarean section was higher in women managed as outpatients compared to those managed as inpatient.

The Rate of Cervical Length Shortening in the Management of Vasa Previa.

There is no consensus about the optimal surveillance strategy in women with a diagnosis of vasa previa. The aim of this study was to evaluate the role of the rate of change in cervical length measurements in the management of singleton pregnancies with a diagnosis of vasa previa. We performed a retrospective case-control study of our databases for pregnancies with a prenatal diagnosis of vasa previa that were followed with transvaginal sonography for cervical length and evaluated the impact of the changes in cervical length on the need for emergency cesarean delivery. The cohort included 29 singleton pregnancies with a prenatal diagnosis of vasa previa in the second trimester. There were 14 and 15 pregnancies that underwent elective and emergency cesarean delivery, respectively. The rate of cervical length shortening was significantly slower for women with elective compared to emergency cesarean delivery (median [range], 0.7 [0.1-2.0] versus 1.5 [0.25-3.0] mm/wk; P = .011). For each additional millimeter-per-week decrease in cervical length, the odds of emergency cesarean delivery increased by 6.50 (95% confidence interval, 1.02-41.20). The receiver operating characteristic curve for the rate of cervical length shortening in the prediction of emergency cesarean delivery yielded an area under the curve of 0.85 (95% confidence interval, 0.69-0.99). Our findings indicate an association between the rate of cervical length shortening and the risk of emergency cesarean delivery in pregnancies with a diagnosis of vasa previa in the second trimester. Further multicentric studies are required to validate our data prospectively and, in particular, the role of serial cervical length measurements in determining the optimal delivery time for individual cases.

Prenatally Diagnosed Vasa Previa: A Single-Institution Series of 96 Cases.

To describe outcomes for a large cohort of women with prenatally diagnosed vasa previa, determine the percentage in patients without risk factors, and compare delivery timing and indications for singletons and twins. This was a retrospective case series of women with prenatally diagnosed vasa previa delivered at a single tertiary center over 12 years. Potential participants were identified using hospital records and perinatal databases. Patients were included if vasa previa was confirmed at delivery and by pathologic examination. Maternal and newborn data were gathered from medical records. There were 77 singleton and 19 twin pregnancies with a prenatal diagnosis of vasa previa. There was one neonatal death from congenital heart disease. Perinatal management of recommended elective hospitalizations with corticosteroid administration and elective early delivery resulted in average gestational age for delivery in singletons at 34.7±1.6 weeks and 32.8±2.2 weeks for twins. Among the 77 singletons, delivery was elective in 48, as a result of contractions or labor in 21, bleeding in four, nonreassuring tracing in two, asymptomatic cervical shortening in one, and preeclampsia in one. Among 19 twins, delivery was elective in six and for contractions or labor in 13. Sixty-eight percent of twins compared with 37% of singletons had nonelective delivery (P<.05). Delivery occurred by 32 weeks of gestation in 6.4% of singletons and 26% of twins (P<.05) and by 34 weeks of gestation in 11% of singletons and 58% of twins (P<.001). Six neonates (5.2%) had major anomalies, all prenatally detected. Respiratory distress syndrome occurred in 57.1% of singletons and 65.7% of twins. Nineteen singletons (24.7%) had no risk factors for vasa previa. Planned preterm delivery for women with prenatally diagnosed vasa previa resulted in elective delivery for singletons in 62% and for twins 32%. Gestational age at birth on average was 34.7 weeks for singletons and 32.8 weeks of gestation for twins. Major anomalies were frequent as was respiratory distress syndrome. Elective delivery between 34 and 35 weeks of gestation for singletons is reasonable. As a result of the high rate of nonelective delivery in twins, delivery at 32-34 weeks of gestation may be risk-beneficial. The high rate of singletons without risk factors for vasa previa reinforces the recommendation to screen routinely for cord insertion site.

#37: Diagnosis and management of vasa previa

Vasa previa occurs when fetal blood vessels that are unprotected by the umbilical cord or placenta run through the amniotic membranes and traverse the cervix. If membranes rupture, these vessels may rupture, with resultant fetal hemorrhage, exsanguination, or even death. Prenatal diagnosis of vasa previa by ultrasound scans is approximately 98%. Approximately 28% of prenatally diagnosed cases result in emergent preterm delivery. Management of prenatally diagnosed vasa previa includes antenatal corticosteroids between 28-32 weeks of gestation, considerations for preterm hospitalization at 30-34 weeks of gestation, and scheduled delivery at 34-37 weeks of gestation.

Systematic review of accuracy of ultrasound in the diagnosis of vasa previa.

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. 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. 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%. The accuracy of ultrasound in the diagnosis of vasa previa is high when performed transvaginally in combination with color Doppler.

P15.22: Effectiveness of time prenatal diagnosis of vasa previa: a report of three cases

<scp>P</scp>15.22: Effectiveness of time prenatal diagnosis of vasa previa: a report of three cases

Prenatal diagnosis and management of vasa previa: A 6‐year review

To evaluate the methods of screening and prenatal diagnosis of vasa previa. We reviewed cases of vasa previa in our hospital between January 2002 and December 2007. During this period, we visualized the site of cord insertion using transabdominal ultrasonography and observed the internal os using gray-scale transvaginal ultrasonography. A diagnosis of vasa previa was confirmed by transvaginal color Doppler imaging. We encountered 10 cases of vasa previa among 5131 deliveries. All cases had one or more known risk factors. In all of the four cases that underwent screening in the second trimester (i.e. between 20 and 25 weeks of gestation), the diagnosis was correct. Routine ultrasonography detected in only three of the other six cases of vasa previa that were referred to our hospital after 26 weeks of gestation. Of the other three cases referred after 26 weeks of gestation, in two cases vasa previa was detected by detailed examination using color Doppler transvaginal ultrasonography after fetal heart rate monitoring detected the presence of non-reassuring fetal status; in the remaining case, we were unable to make an antenatal diagnosis. Non-reassuring fetal status was seen on fetal heart rate monitoring in four of the five detected cases complicated by preterm labor. We consider that the best timing of antenatal screening for vasa previa is the second trimester. Non-reassuring fetal heart rate pattern without other possible causes warrants detailed examination of vasa previa.

Clinical significances of magnetic resonance imaging in prenatal diagnosis of vasa previa in a woman with bilobed placentas

We report a case of a pregnant woman diagnosed as having vasa previa by magnetic resonance imaging (MRI). A parous woman was referred to our hospital at 31 weeks of gestation due to suspicion of placenta previa. Transvaginal ultrasound examination together with the Doppler techniques showed a fetal vessel on a lesion of low and high mixed echogenecities over the internal os, but could not confirm whether it was placental tissue or not. MRI demonstrated that it was not placenta but a hemorrhage between bilobed placentas and that the vessel was running over the internal os freely from the placenta. At 34 weeks of gestation, emergency cesarean section was performed due to increasing vaginal bleeding. MRI should be useful in the diagnosis of vasa previa when the relation between the position of the placenta and that of suspicious vessels cannot be adequately evaluated by ultrasound.

P09.23: Prenatal diagnosis of vasa previa with three‐dimensional ultrasonography: report of two cases

P09.23: Prenatal diagnosis of vasa previa with three‐dimensional ultrasonography: report of two cases

Second trimester low‐lying placenta and in‐vitro fertilization? Exclude vasa previa

We report the prenatal diagnosis of vasa previa using transvaginal sonography and color Doppler. This case supports the previously reported association of vasa previa with second trimester low-lying placentas and in-vitro fertilization. Sonographic examination for vasa previa should be considered in pregnancies with low-lying placentas and those resulting from in-vitro fertilization. J. Matern.-Fetal Med. 2000;9:370–372. © 2000 Wiley-Liss, Inc.

Second trimester low-lying placenta and in-vitro fertilization? Exclude vasa previa

We report the prenatal diagnosis of vasa previa using transvaginal sonography and color Doppler. This case supports the previously reported association of vasa previa with second trimester low-lying placentas and in-vitro fertilization. Sonographic examination for vasa previa should be considered in pregnancies with low-lying placentas and those resulting from in-vitro fertilization.

Vasa previa: Prenatal diagnosis with transvaginal color Doppler flow imaging

Vasa previa carries a significant risk for fetal exsanguination and death at the time of membrane rupture. The diagnosis is rarely made before the onset of vaginal bleeding. We report the prenatal diagnosis of vasa previa with transvaginal color Doppler flow imaging in an asymptomatic patient with a succenturiate placenta.