Impact of targeted scanning protocols on perinatal outcomes in pregnancies at risk of placenta accreta spectrum or vasa previa

European association of perinatal medicine (EAPM) position statement: Screening, diagnosis and management of congenital anomalies of the umbilical cord

Congenital anomalies of the umbilical cord are associated with an increased risk of pregnancy and perinatal complications. Some anomalies of the cord have a higher prevalence than other fetal structural anomalies. The most common anomalies are the absence of an umbilical artery and velamentous insertion of the cord (with or without vasa previa). These anomalies, even when not associated with fetal structural defects, increase the risk of adverse perinatal outcome including, fetal growth restriction and stillbirth. In the absence of prenatal diagnosis, vasa previa is associated with the highest perinatal morbidity and mortality of all congenital anomalies of the umbilical cord. Most cases can be detected by ultrasound from the beginning of the second trimester and should be included in the routine mid-pregnancy ultrasound examination. Documentation should include cord insertion site, number of vessels in the cord, and if other pathologies have been detected. Pregnancies at increased risk of velamentous cord insertion should be screened for vasa previa using transvaginal ultrasound and colour Doppler imaging. If a velamentous cord insertion or isolated single umbilical artery is detected, individualised follow-up during pregnancy and tailored obstetric management are indicated.

Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus

BACKGROUND

There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies.

OBJECTIVE

This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique.

STUDY DESIGN

A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from "strongly disagree"=1 to "strongly agree"=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated.

RESULTS

A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa.

CONCLUSION

Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

Impact of Universal Vasa Previa Screening With Color Doppler During the OB Ultrasound Anatomy Scan

OBJECTIVES

Our institution introduced universal vasa previa (VP) screening utilizing transabdominal ultrasound with color Doppler for all pregnancies at the second trimester anatomy scan. Our study sought to describe the clinical impact of this intervention.

METHODS

Radiology records from the 12 months pre- and post-intervention were queried for "vasa previa." Records included for analysis were those with a first-time diagnosis or discussion of VP at the anatomy scan. Cases were categorized by outcome: (Group 1) True VP, with subgroups A, unresolved by time of delivery and B, resolved by delivery; (Group 2) False positives; (Group 3) Possible VP without definitive diagnosis; and (Group 4) VP ruled out, for example, "no features of VP." Group size was expressed as a percentage of total anatomy scans during pre- or post-intervention periods respectively. Absolute and relative percent change were calculated for each group.

RESULTS

In the pre-intervention period, 1 case (0.36% of total scans) was categorized in Group 1A, 1 case (0.36%) in Group 3, and 7 cases (2.53%) in Group 4. In the post-intervention period, 2 cases (0.30%) were in Group 1A, 4 cases (0.61%) in Group 1B, 2 cases (0.30%) in Group 2, 1 case (0.15%) in Group 3, and 7 cases (1.06%) in Group 4. There was a +153% relative change in true positives, from 0.36 to 0.91%.

CONCLUSIONS

Universal color Doppler screening may have increased detection (sensitivity) while simultaneously increasing false positives (decreased specificity). While decreasing sensitivity is not ideal, this is acceptable given the potential catastrophic outcome of a missed VP.

Incidence and causes of perinatal death in prenatally diagnosed vasa previa: a systematic review and meta-analysis

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 I2. 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; I2=0.0%). The pooled perinatal mortality attributed to vasa previa was 0.51% (95% confidence interval, 0.23-1.14; I2=0.0%). Stillbirth and neonatal death were reported in 0.20% (95% confidence interval, 0.05-0.80; I2=0.0%) and 0.77% (95% confidence interval, 0.40-1.48; I2=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.

Clinical Outcomes of a False-Positive Antenatal Diagnosis of Placenta Accreta Spectrum

OBJECTIVE

 Antenatal diagnosis of placenta accreta spectrum (PAS) is critical to reduce maternal morbidity. While clinical outcomes of women with PAS have been extensively described, little information is available regarding the women who undergo cesarean delivery with a presumptive PAS diagnosis that is not confirmed by histopathologic examination. We sought to examine resource utilization and clinical outcomes of this group of women with a false-positive diagnosis of PAS.

STUDY DESIGN

 This is a retrospective analysis of patients with prenatally diagnosed PAS cared for between 2015 and 2020 by our multidisciplinary PAS team. Maternal outcomes were examined. Univariate analysis was performed and a multivariate model was employed to compare outcomes between women with and without histopathologically confirmed PAS.

RESULTS

 A total of 162 patients delivered with the preoperative diagnosis of PAS. Of these, 146 (90%) underwent hysterectomy and had histopathologic confirmation of PAS. Thirteen women did not undergo the planned hysterectomy. Three women underwent hysterectomy but pathologic examination did not confirm PAS. In comparing women with and without pathologic confirmation of PAS, the false-positive PAS group delivered later in pregnancy (34 vs. 33 weeks of gestation, p = 0.015) and had more planned surgery (88 vs. 47%, p = 0.002). There was no difference in skin incision type or hysterotomy placement for delivery. No significant difference in either the estimated blood loss or blood components transfused was noted between groups.

CONCLUSION

 Careful intraoperative evaluation of women with preoperatively presumed PAS resulted in a 3/149 (2%) retrospectively unnecessary hysterectomy. Management of women with PAS in experienced centers benefits patients in terms of both resource utilization and avoidance of unnecessary maternal morbidity, understanding that our results are produced in a center of excellence for PAS. We also propose a management protocol to assist in the avoidance of unnecessary hysterectomy in women with the preoperative diagnosis of PAS.

KEY POINTS

· Evaluation and delivery planning of patients with suspected placenta accreta spectrum in experienced centers provides acceptable outcomes.. · Under specific circumstances, delivery of placenta may be attempted if placenta accreta is suspected.. · Patients with suspected placenta accreta rarely undergo unindicated hysterectomy..

The role of transvaginal ultrasound in the third-trimester evaluation of patients at high risk of placenta accreta spectrum at birth

BACKGROUND

Transvaginal ultrasound imaging has become an essential tool in the prenatal evaluation of the lower uterine segment and anatomy of the cervix, but there are only limited data on the role of transvaginal ultrasound in the management of patients at high risk of placenta accreta spectrum at birth.

OBJECTIVE

This study aimed to evaluate the role of transvaginal sonography in the third trimester of pregnancy in predicting outcomes in patients with a high probability of placenta accreta spectrum at birth.

STUDY DESIGN

This was a retrospective analysis of prospectively collected data of patients presenting with a singleton pregnancy and a history of at least 1 previous cesarean delivery and patients diagnosed prenatally with an anterior low-lying placenta or placenta previa delivered electively after 32 weeks of gestation. All patients had a least 1 detailed ultrasound examination, including transabdominal and transvaginal scans, within 2 weeks before delivery. Of note, 2 experienced operators, blinded to the clinical data, were asked to make a judgment on the likelihood of placenta accreta spectrum as a binary, low or high-probability of placenta accreta spectrum, and to predict the main surgical outcome (conservative vs peripartum hysterectomy). The diagnosis of accreta placentation was confirmed when one or more placental cotyledons could not be digitally separated from the uterine wall at delivery or during the gross examination of the hysterectomy or partial myometrial resection specimens.

RESULTS

A total of 111 patients were included in the study. Abnormal placental tissue attachment was found in 76 patients (68.5%) at birth, and histologic examination confirmed superficial villous attachment (creta) and deep villous attachment (increta) in 11 and 65 cases, respectively. Of note, 72 patients (64.9%) had a peripartum hysterectomy, including 13 cases with no evidence of placenta accreta spectrum at birth because of failure to reconstruct the lower uterine segment and/or excessive bleeding. There was a significant difference in the distribution of placental location (X2=12.66; P=.002) between transabdominal and transvaginal ultrasound examinations, but both ultrasound techniques had similar likelihood scores in identifying accreta placentation that was confirmed at birth. On transabdominal scan, only a high lacuna score was significantly associated (P=.02) with an increased chance of hysterectomy, whereas on transvaginal scan, significant associations were found between the need for hysterectomy and the thickness of the distal part of the lower uterine segment (P=.003), changes in the cervix structure (P=.01), cervix increased vascularity (P=.001), and the presence of placental lacunae (P=.005). The odds ratio for peripartum hysterectomy were 5.01 (95% confidence interval, 1.25-20.1) for a very thin (<1-mm) distal lower uterine segment and 5.62 (95% confidence interval, 1.41-22.5) for a lacuna score of 3+.

CONCLUSION

Transvaginal ultrasound examination contributes to both prenatal management and the prediction of surgical outcomes in patients with a history of previous cesarean delivery with and without ultrasound signs suggestive of placenta accreta spectrum. Transvaginal ultrasound examination of the lower uterine segment and cervix should be included in clinical protocols for the preoperative evaluation of patients at risk of complex cesarean delivery.

Vasa Previa

Vasa previa refers to unprotected fetal vessels running through the membranes over the cervix. Until recently, this condition was associated with an exceedingly high perinatal mortality rate attributable to fetal exsanguination when the membranes ruptured. However, ultrasonography has made it possible to diagnose the condition prenatally, allowing cesarean delivery before labor or rupture of the membranes. Several recent studies have indicated excellent outcomes with prenatally diagnosed vasa previa. However, outcomes continue to be dismal when vasa previa is undiagnosed before labor. Risk factors for vasa previa include second-trimester placenta previa and low-lying placentas, velamentous cord insertion, placentas with accessory lobes, in vitro fertilization, and multifetal gestations. Recognition of individuals who are at risk and screening them will greatly decrease the mortality rate from this condition. Because of the relative rarity of vasa previa, there are no randomized controlled trials to guide management. Therefore, recommendations on the diagnosis and management of vasa previa are based largely on cohort studies and expert opinion. This Clinical Expert Series review addresses the epidemiology, pathophysiology, natural history, diagnosis and management of vasa previa, as well as innovative treatments for the condition.

Guideline No. 439: Diagnosis and Management of Vasa Previa

OBJECTIVE

To summarize the current evidence and to make recommendations for diagnosis and classification of vasa previa and for management of women with this diagnosis.

TARGET POPULATION

Pregnant women with vasa previa or low-lying fetal vessels.

OPTIONS

To manage vasa previa in hospital or at home, and to perform a cesarean delivery preterm or at term, or to allow a trial of labour when a diagnosis of vasa previa or low-lying fetal vessels is suspected or confirmed.

OUTCOMES

Prolonged hospitalization, preterm birth, rate of cesarean delivery, and neonatal morbidity and mortality.

BENEFITS, HARMS, AND COSTS

Women with vasa previa or low-lying fetal vessels are at an increased risk of maternal and fetal or postnatal adverse outcomes. These outcomes include a potentially incorrect diagnosis, need for hospitalization, unnecessary restriction of activities, an early delivery, and an unnecessary cesarean delivery. Optimization of diagnostic and management protocols can improve maternal and fetal or postnatal outcomes.

EVIDENCE

Medline, Pubmed, Embase, and the Cochrane Library were searched from inception to March 2022, using medical subject headings (MeSH) and keywords related to pregnancy, vasa previa, low-lying fetal vessels, antepartum hemorrhage, short cervix, preterm labour, and cesarean delivery. This document presents an abstraction of the evidence rather than a methodological review.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Obstetric care providers, including obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, and radiologists.

TWEETABLE ABSTRACT

Unprotected fetal vessels in placental membranes and cord that are close to the cervix, including vasa previa, need careful characterization by sonographic examination and evidence-based management to reduce risks to the baby and the mother during pregnancy and delivery.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Directive clinique no 439: Diagnostic et prise en charge du vasa prævia

OBJECTIF

Résumer les données probantes actuelles et énoncer des recommandations pour le diagnostic et la classification du vasa prævia et pour la prise en charge des femmes ayant reçu ce diagnostic.

POPULATION CIBLE

Femmes enceintes présentant un vasa prævia ou des vaisseaux ombilicaux péricervicaux.

OPTIONS

En cas de diagnostic soupçonné ou confirmé de vasa prævia ou de vaisseaux ombilicaux péricervicaux, prendre en charge la patiente à l'hôpital ou à domicile, puis pratiquer une césarienne avant terme ou à terme ou entreprendre une épreuve de travail. RéSULTATS: Hospitalisation prolongée, accouchement prématuré, césarienne et morbidité et mortalité néonatales. BéNéFICES, RISQUES ET COûTS: Les femmes ayant un vasa prævia ou des vaisseaux ombilicaux péricervicaux présentent un risque accru d'issues défavorables maternelles, fœtales ou postnatales, à savoir un diagnostic potentiellement erroné, un besoin d'hospitalisation, une restriction inutile des activités, un accouchement précoce et une césarienne inutile. L'optimisation des protocoles de diagnostic et de prise en charge peut améliorer les issues maternelles, fœtales et postnatales. DONNéES PROBANTES: Des recherches ont été effectuées dans les bases de données Medline, PubMed, Embase et Cochrane Library, de leur création jusqu'à mars 2022, à partir de termes MeSH et de mots clés liés à la grossesse, au vasa prævia, aux vaisseaux prævia, à l'hémorragie ante partum, au col court, au travail prématuré et à la césarienne. Le présent document est un résumé des données probantes et non pas une revue méthodologique. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et faibles). PROFESSIONNELS CONCERNéS: Fournisseurs de soins obstétricaux, y compris obstétriciens, médecins de famille, infirmières, sages-femmes, spécialistes en médecine fœto-maternelle et radiologistes. RéSUMé POUR TWITTER: En cas de cordon et de vaisseaux ombilicaux non protégés dans les membranes près du col (vasa prævia y compris), une caractérisation échographique et une prise en charge avisée s'imposent pour réduire les risques pour le bébé et la mère pendant la grossesse et l'accouchement.

Evaluation of the Tramline Sign in the Prediction of Placenta Accreta Spectrum and Perioperative Outcomes in Anterior Placenta Previa

PURPOSE

 To evaluate perioperative outcomes and the prognostic role of the tramline sign in a cohort of women with anterior placenta previa.

MATERIALS AND METHODS

 Retrospective analysis of 3D ultrasound volumes from women with anterior placenta previa who underwent ultrasound examination beyond 32 weeks. 3D and 3D color volumes were obtained from a sagittal section of the uterus bisecting a partially full bladder and processed using Crystal Vue and Crystal Vue Flow rendering to look for the "tramline sign". "Partial obliteration" was defined as a loss of some or part of the uterine-serosal interface and "full obliteration" as when both interfaces were interrupted. Postnatal ascertainment of placenta accreta spectrum (PAS) was confirmed by findings recorded intraoperatively or on a pathology report.

RESULTS

 65 cases were included. The tramline sign was "partially" (17) or "fully" (19) obliterated in 36 cases (55.4 %), and present in 29 (44.6 %). Obliteration was associated with earlier gestational age at delivery (35 + 1 (26 + 3-38 + 3) vs. 36 + 4 (25 + 3-38 + 0) weeks, p = 0.005), greater estimated blood loss (800 (400-11 000) vs. 600 (300-2100) mls, p = 0.003), longer operative time (155 (60-240) vs. 54 (25-80) minutes, p < 0.001), higher rate of hysterectomy (97.2 % vs. 0.0 %, p < 0.001), longer postoperative admission (7 (3-19) vs. 3 (1-5) days, p < 0.001) and a 100 % rate of postnatal diagnosis of PAS. The finding of an "obliterated" tramline sign identified all women that required hysterectomy and all cases of PAS.

CONCLUSION

 A "partially or fully obliterated" tramline sign is strongly associated with indicators of operative complexity, the postnatal confirmation of PAS, and the need for peripartum hysterectomy.

The MRI estimations of placental thickness and cervical length correlate with postpartum hemorrhage (PPH) in patients with risk for placenta accreta spectrum (PAS) disorders

INTRODUCTION

This study aims to identify whether placental thickness and cervical length measured by MRI correlate with postpartum hemorrhage (PPH) in patients at high risk for placenta accreta spectrum (PAS) disorders.

METHODS

The placental thickness and cervical length of 200 patients from October 2017 to October 2021 were retrospectively measured. The mid-sagittal plane of the placentas was measured by 2 independent radiologists using MRI. Partial correlation analysis was used to characterize the correlation between placental thickness, cervical length and estimated blood loss during surgery. The correlation between clinical features, placental thickness, cervical length and PPH was evaluated with univariate and multivariate analyses. A nomogram was constructed based on the logistic regression.

RESULTS

Placental thickness was positively correlated with the estimated blood loss during delivery, while cervical length had a negative correlation with it, based on the adjustment for gestational age. Multivariate analyses revealed that prior cesarean section, placenta previa, increased placental thickness(≧4.35 cm) and short cervical length（< 3.05 cm） were independent risk factors for PPH. When the 4 risk factors were combined together, the AUC was the highest, 0.773 (95%CI 0.707-0.840).

DISCUSSION

Placental thickness and cervical length correlated with PPH. The nomogram constructed based on prior cesarean section, placenta previa, placental thickness and cervical length can be used to recognize patients with a higher risk of PPH.

Timing of birth and adverse pregnancy outcomes in cases of prenatally diagnosed vasa previa: a systematic review and meta-analysis

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.

Analysis of risk factors for massive intraoperative bleeding in patients with placenta accreta spectrum

BACKGROUND

To analyze relevant factors for massive postpartum hemorrhage in women with placenta accreta spectrum in order to improve the ability to identify those at risk for intraoperative bleeding and improve outcome.

METHODS

This study is a retrospective study and based on data from Hospital electronic medical record. Placenta accreta patients who delivered by cesarean section at Peking University Third Hospital from September 2017 to December 2019 were selected and included. According to the amount of intraoperative bleeding, they were categoried into the massive bleeding group (bleeding volume ≥ 2000 mL, 68 cases) and non-massive bleeding group (bleeding volume < 2000 mL, 99 cases). Univariate analysis and multivariate logistic regression were used to analyze the correlations between related risk factors or ultrasound imaging characteristics and the severity of bleeding during operation.

RESULTS

(1) There were statistically significant differences in gravidity, parity, number of prior cesarean deliveries and placenta accreta ultrasound scores (P < 0.05) between the two groups of patients. (2) Among the ultrasonographic indicators, the disappearance of the post-placental clear space, the emergence of cross-border blood vessels in the region of subplacental vascularity, interruption or disappearance of the bladder line, and the presence of the cervical blood sinus had the most significant correlation with hemorrhage during PAS (P < 0.05).

CONCLUSION

The presence of cervical blood sinus, interruption or disappearance of bladder line, the disappearance of the post-placental clear space and abnormal subplacental vascularity are independent risk factors for massive hemorrhage during PAS. We should pay more attention to these indicators in prenatal ultrasound examination in order to reduce the intraoperative bleeding and improve maternal outcomes.

Pregnancy and Delivery Outcomes in Women With Persistent Versus Resolved Low-Lying Placenta in the Late Third Trimester

OBJECTIVES

The safest mode of delivery in low-lying placenta is debatable. Little is known about outcomes in low-lying placenta resolved during the late third trimester. We compare outcomes of women with persistent versus resolved low-lying placenta.

METHODS

A retrospective analysis on a prospective cohort of women with low-lying placenta confirmed at 28-30 weeks sonography (01/2009 to 03/2018). Women were followed up serially every 2 to 3 weeks until delivery to assess the placental edge-to-internal os distance (IOD), and included if scan was performed within 28 days before delivery.

RESULTS

There were 86 women: in 21 the low-lying placenta resolved, whereas in 65 persisted (n = 15 IOD 1-10 mm, n = 50 IOD 11-20 mm). Antepartum bleeding associated with higher rates of urgent cesarean delivery in 1-10 mm (P = .041) but not in 11-20 mm (P = 1.000) and >20 mm (P = .333). Among women with IOD >10 mm allowed to labor, vaginal delivery occurred in 76.7% (11-20 mm) and 94.1% (>20 mm) (P = .155), with no difference according to parity (70% and 80% in multiparas, P = .696; 60% and 72.7% in nulliparas, P = .698). Severe PPH (P = .922) and hemoglobin drop (P = .109) were similar among groups. Women with IOD 11-20 mm and >20 mm and vaginal delivery bled less than women with similarly located placenta and cesarean delivery (P = .009 and P = .048).

CONCLUSIONS

Women with IOD >10 mm have high chances of deliver vaginally with no further increase of their hemorrhagic risk. Success of vaginal delivery is independent of parity and antepartum bleeding. Labor should be managed in an adequate hospital setting.

Comparison between a prenatal sonographic scoring system and a clinical grading at delivery for Placenta Accreta Spectrum disorders

OBJECTIVE

Placenta Accreta Spectrum (PAS) disorders have become a major iatrogenic obstetric complication worldwide. Data on the accuracy of ultrasound examination diagnosis are limited by incomplete confirmation and variability in the description of the different grades of PAS at delivery. The aim of this study was to compare our prenatal routine sonographic screening and diagnostic scoring system with a standardized clinical grading system at birth in patient at risk of PAS.

STUDY DESIGN

This is a retrospective cohort study of 607 pregnant patients with at least one prior cesarean delivery between December 2013 and December 2018. All patients were assessed for PAS using our institutional prenatal sonographic scoring system and the corresponding ultrasound findings were compared with those of a standardized clinical intra-operative macroscopic grading system of the degree of accreta placentation at vaginal birth or laparotomy.

RESULTS

PAS was diagnosed clinically at birth in 50 (8.2%) cases, 17 of which were confirmed by histopathology. A low (score ≤ 5), medium (score 6-7), high (score ≥ 8) probability for PAS was reported in 502, 61 and 44 cases, respectively. The probability score increased significantly (p < .001) in women ≥2 prior cesarean deliveries, with an anterior low-lying/placenta previa, with absent clear space, increased in retroplacental vascularity and with the size and numbers of lacunae. The number of cases classified clinically as grade 1 (non-PAS) and 3 (adherent PAS) was significantly (p < .001) lower in women with a high probability score whereas the rates of the other grades was significantly (p < .001) higher. The widest discrepancy between ultrasound probability score and clinical grade was found for grade 2 which, describes a partial placental adherence and grades 4 and 5 which, refer to placental percreta which describes tissue having invade trough the uterine serosa and beyond.

CONCLUSIONS

Both ends of the spectrum of accreta placentation remain difficult to diagnose antenatal and clinically at birth, in particular when no histopathologic confirmation is available. There is a need to develop ultrasound accuracy score systems that can differentiate between the different grades of PAS and which are validated by standardized clinical and pathology protocols.

In Vitro Fertilization in a Nulliparous Female Resulting in Placenta Increta and Postpartum Hemorrhage

A 32-year-old female with unexplained infertility delivered a healthy male infant at 39 weeks 0 days gestational age; the pregnancy was facilitated by in vitro fertilization. Shortly after delivery, she was found to have a morbidly adherent placenta. Attempted removal resulted in postpartum hemorrhage and ultimately hysterectomy after attempting multiple fertility preserving methods to achieve hemostatic control. Pathology results revealed a diagnosis of a 0.1 cm placenta increta (Grade 2 placental villi invasion), the least common diagnosis within the placenta accreta spectrum (PAS). Likely due to the small point of trophoblastic invasion, the diagnosis and outcome were not foreseen. This case highlights the need for additional data collection and development of standardized guidelines for the diagnosis and management of PAS, given a patient’s risk factors. Current research may be limited by stigmatization surrounding infertility and reproductive-altering surgeries (e.g. hysterectomy). Additionally, counseling in all stages of pregnancy is critical to achieving the best patient-centered outcomes.

Pregnancy-Related Hysterectomy for Peripartum Hemorrhage: A Literature Narrative Review of the Diagnosis, Management, and Techniques

Postpartum hemorrhage is a life-threatening situation, in which hysterectomy can be performed to prevent maternal death. However, it is associated with high rates of maternal morbidity and mortality and permanent infertility. The incidence of pregnancy-related hysterectomy varies across countries, but its main indications are the following: uterine atony and placenta spectrum (PAS) disorders. PAS disorder prevalence is rising during the last years, mainly due to the increased number of cesarean sections. As a result, obstetricians should be aware of the difficulties of this emergent condition and improve its accurate antenatal diagnosis rates, as well as its modern management strategies. Of course, special skills are required during a pregnancy-related hysterectomy, so these patients should be referred to centers of excellence in antenatal care, where a multidisciplinary team approach is followed. This study is a narrative review of the literature of the last 5 years (PubMed, Cochrane) regarding postpartum hemorrhage to offer obstetricians up-to-date knowledge on this pregnancy-related life-threatening issue. However, there is a lack of available high-quality data, because most published papers are retrospective case series or observational cohorts.

Systematic screening for vasa previa at the 20-week anomaly scan

INTRODUCTION

The presence of vasa previa carries a high risk for severe fetal morbidity and mortality due to fetal bleeding caused by injury to unprotected fetal vessels when rupture of membranes occurs. Previously, it has been shown that prenatal diagnosis significantly improves the outcome. However, systematic screening for vasa previa is not generally performed and clinical studies demonstrating the performance of systematic screening for vasa previa in routine clinical practice are rare. The objective of this study was to assess the performance of systematic screening for vasa previa by determining placental cord insertion at the 20-week anomaly scan.

MATERIAL AND METHODS

This is a retrospective study of 6038 pregnant women between 18+0 and 24+0 gestational weeks who were prospectively screened for vasa previa by depiction of the site of placental cord insertion at the 20-week anomaly scan. Pregnancies with marginal or velamentous cord insertion underwent vaginal sonography for examination for vasa previa. In cases with succenturiate or bilobed placentas, the bridging vessels were depicted, and vaginal sonography was performed if necessary.

RESULTS

There were 21 cases of vasa previa and all were diagnosed prenatally. In 18 cases, the cord insertion was marginal or velamentous. The remaining three cases had placental anomalies, which necessitated a detailed examination. All pregnancies with vasa previa were delivered at a mean of 35.2 (SD 1.8) gestational weeks by cesarean section. Among pregnancies affected by vasa previa, all fetuses survived. The median birthweight was 2390 g (range 1200-2990 g) and the mean umbilical artery pH 7.34 (SD 0.04). The median 5-min APGAR score was nine (range 7-10). None of the fetuses or neonates died or required blood transfusions. In all pregnancies of the whole cohort which were complicated by fetal or neonatal demise and in neonates with a 5-min APGAR score ≤5 and/or an umbilical artery pH ≤7.10, fetal blood loss was excluded as a cause of the poor obstetric outcome.

CONCLUSIONS

Screening for vasa previa is feasible and efficient, taking into account the site of placental cord insertion in pregnancies not affected by placenta previa and bilobed and succenturiate placenta.

Characteristics and outcomes of pregnant women with placenta accreta spectrum in Italy: A prospective population-based cohort study

Introduction

Placenta accreta spectrum (PAS) is a rare but potentially life-threatening event due to massive hemorrhage. Placenta previa and previous cesarean section are major risk factors for PAS. Italy holds one of the highest rates of primary and repeated cesarean section in Europe; nonetheless, there is a paucity of high-quality Italian data on PAS. The aim of this paper was to estimate the prevalence of PAS in Italy and to evaluate its associated factors, ante- and intra-partum management, and perinatal outcomes. Also, since severe morbidity and mortality in Italy show a North-South gradient, we assessed and compared perinatal outcomes of women with PAS according to the geographical area of delivery.

Material and methods

This was a prospective population-based study using the Italian Obstetric Surveillance System (ItOSS) and including all women aged 15–50 years with a diagnosis of PAS between September 2014 and August 2016. Six Italian regions were involved in the study project, covering 49% of the national births. Cases were prospectively reported by a trained clinician for each participating maternity unit by electronic data collection forms. The background population comprised all women who delivered in the participating regions during the study period.

Results

A cohort of 384 women with PAS was identified from a source population of 458 995 maternities for a prevalence of 0.84/1000 (95% CI, 0.75–0.92). Antenatal suspicion was present in 50% of patients, who showed reduced rates of blood transfusion compared to unsuspected patients (65.6% versus 79.7%, P = 0.003). Analyses by geographical area showed higher rates of both concomitant placenta previa and prior CS (62.1% vs 28.7%, P<0.0001) and antenatal suspicion (61.7% vs 28.7%, P<0.0001) in women in Southern compared to Northern Italy. Also, these women had lower rates of hemorrhage ≥2000 mL (29.6% vs 51.2%, P<0.0001), blood transfusion (64.5% vs 87.5%, P = 0.001), and severe maternal morbidity (5.0% vs 11.1%, P = 0.036). Delivery in a referral center for PAS occurred in 71.9% of these patients.

Conclusions

Antenatal suspicion of PAS is associated with improved maternal outcomes, also among high-risk women with both placenta previa and prior CS, likely because of their referral to specialized centers for PAS management.

Placental thickness correlates with placenta accreta spectrum (PAS) disorder in women with placenta previa

OBJECTIVE

To evaluate the association of placental thickness with placenta accreta spectrum disorder in placenta previa.

METHODS

In this IRB-approved, retrospective study, ultrasound (US) reports were retrospectively queried for keyword previa. US performed closest to mid-gestation were included. Three measurements were performed at the thickest portion of the placenta on longitudinal transabdominal images. Operative reports and surgical pathology were used as the reference standard. Statistical analysis was performed using unpaired T-tests and receiver operating curve (ROC) analysis.

RESULTS

Sixty-five patients with placenta previa were included: 38 with PAS disorder and 27 without PAS disorder, clinically or pathologically. 38/38 (100%) patients of PAS group and 16/27 (59.3%) patients of non-PAS group had history of prior cesarean section. The average placental thickness was 4.3 cm (range 1.8 cm to 7.8 cm) for PAS group and 3.0 cm (range 0.6 cm to 5.3 cm) for non-PAS group (p < 0.001). Placental thickness in patients without PAS disorder and history of prior cesarean section was 3.1 (± 1.1) cm. This was statistically different from patients who had history of prior cesarean section with PAS diagnosis (4.3 cm, P<0.01). Using ROC analysis, a threshold measurement of 4.5 cm leads to sensitivity of 50% and specificity of 96%.

CONCLUSION

Our results demonstrate that among women with placenta previa, increased placental thickness at lower uterine segment correlates with placenta accreta spectrum disorder. A threshold of 4.5 cm can be useful for screening patients with placenta previa and risks factors for PAS.

Perinatal outcome of pregnancies with prenatal diagnosis of vasa previa: systematic review and 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 I² 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.

Midgestational pre-labor spontaneous uterine rupture: a systematic review

OBJECTIVE

Second and early third-trimester uterine rupture in a non-laboring woman is a very rare and life-threatening condition for both mothers and newborns. However, there are scant epidemiologic data on this event.

STUDY DESIGN

Literature searches using Medical Subject Headings (MeSH) and non-MeSH terms were conducted in the PubMed/MEDLINE, Google Scholar and Embase databases from 1988 to 2020. Abstracts were reviewed and selected if they reported on uterine rupture in the second and third trimester. Uterine rupture was characterized as a full-thickness uterine wall defect. A total of 80 singleton intrauterine pregnancies between gestational ages of 14 and 34 weeks' gestation were included.

RESULTS

The mean gestational age at diagnosis of uterine rupture was 22.4 ± 5.4 weeks. The associated events in obstetric history for uterine rupture were: ≥1 previous cesarean section (45%; 36/80 of the cases), previous uterine rupture (10%; 8/80), previous classical uterine incision (7.5%; 6/80), myomectomy (25%; 20/80) and congenital uterine malformations (16.3%; 13/80 of the cases). Uterine ruptures were associated with a short IP interval in 13.7% (11/80) and 43.7% (35/80) were associated with abnormal placentation: placenta accreta spectrum (PAS) disorders (n = 26), placenta previa (n = 2) and placenta previa and PAS (n = 7). The rate of related prenatal ultrasound findings was 67.5%. Cesarean hysterectomy was performed in 27% of the cases. Maternal death was reported in 2.5% (2/80). For the neonates delivered ≥24 weeks' gestation (n = 27) peripartum fetal death was reported in 33.3% (9/27).

CONCLUSIONS

Midgestational pre-labor spontaneous uterine rupture is not an anecdotal event and may follow the worldwide increasing rate of cesarean sections. Health care providers should be familiar with the associated factors, presenting symptoms and complications of this obstetric emergency.

A rare case of extensive placenta accreta in twin pregnancy after GnRH agonist treatment of adenomyosis

BACKGROUND

Adenomyosis remains an enigma for the reproductive endocrinologist. It is thought to contribute to sub-fertility, and its only curative treatment is hysterectomy. However, studies have documented increased live birth rates in women with adenomyosis who were treated with gonadotropin releasing hormone agonist (GnRHa).

CASE

Here we present a case of a 52-year-old woman with adenomyosis who had three failed frozen embryo transfers (FETs) prior to initiating a 6-month trial of GnRHa. GnRHa therapy resulted in a decrease in uterine size from 11.5 × 7.9 × 7.0 cm to 7.8 × 6.2 × 5.9 cm and a decrease in the junctional zone (JZ) thickness from 19 to 9 mm. Subsequently, she underwent her fourth FET, which resulted in live birth of twins. The delivery was complicated by expansive accretas of both placentas requiring cesarean hysterectomy. The final pathology of the placentas demonstrated an extensive lack of decidualized endometrium that was even absent outside the basal plate.

CONCLUSIONS

GnRHa therapy in patients with adenomyosis may improve implantation rates after FET. Previous molecular studies indicate that genetic variance in the expression of the gonadotropin releasing hormone receptor (GnRHR) could explain the expansive lack of decidualized endometrium after GnRHa therapy. Further investigations are needed to determine if GnRHa therapy contributes to the pathologic process of placenta accreta.

Second-trimester and early third-trimester spontaneous uterine rupture: A 32-year single-center survey

BACKGROUND

Second-trimester and early third-trimester uterine rupture in a nonlaboring woman is a very rare and life-threatening condition for both mothers and newborns. We aimed to present clinical characteristics, prenatal findings, and maternal and neonatal outcomes following second-trimester and early third-trimester spontaneous antepartum uterine rupture in our institute.

METHOD

The medical records of all women with full-thickness second-trimester and early third-trimester uterine rupture treated in our department from 1988 to 2019 were retrieved from the institutional database and reviewed. Small uterine defects, incomplete ruptures, and silent uterine incision dehiscence were excluded.

RESULTS

From 1988 to 2019, 213 665 deliveries were recorded in our institute. Of these, 12 patients experienced second-trimester or early third-trimester spontaneous uterine rupture. Obstetric history revealed that 50% of the women in each period had undergone previous classical uterine incisions and 50% had a short interpregnancy (IP) interval. The mean age at diagnosis of uterine rupture was 26.3 ± 5.1 weeks. The ruptures were associated with abnormal placentation in 10 cases (83.3%): placenta previa (n = 7); and placenta previa and percreta (n = 3). No maternal mortality occurred. Seven of the 10 (70%) viable newborns survived.

CONCLUSIONS

The increasing rates of cesarean births (CB) may lead to iatrogenic complications including midgestational prelabor spontaneous uterine rupture, an obstetric emergency, which is hard to diagnose. Maternal and neonatal outcomes can be optimized by a greater awareness of the risk factors, recognition of clinical signs and symptoms, and the availability of ultrasound to assist in establishing a diagnosis to enable prompt surgical intervention.

Rethinking Prenatal Screening for Anomalies of Placental and Umbilical Cord Implantation

The most common anomalies of implantation of the placenta and umbilical cord include placenta previa, placenta accreta spectrum, and vasa previa, and are associated with considerable perinatal and maternal morbidity and mortality. There is moderate quality evidence that prenatal diagnosis of these conditions improves perinatal outcomes and the performance of ultrasound imaging in diagnosing them is considered excellent. The epidemiology of placenta previa is well known, and it is standard clinical practice to assess placental location at the routine screening second-trimester detailed fetal anatomy ultrasound examination. In contrast, the prevalence of placenta accreta spectrum and vasa previa in the general population is more difficult to evaluate because detailed confirmatory histopathologic data are not available in most studies. The sensitivity and specificity of ultrasonography for the diagnosis of these anomalies is also difficult to assess. Recent epidemiologic studies show an increase in the incidence of placental and umbilical cord implantation anomalies, which may be the result of increased use of assisted reproductive technology and cesarean delivery. There is good evidence to support targeted standardized protocols for women at high risk and that screening and diagnosing placenta accreta spectrum and vasa previa should be integrated into obstetric ultrasound training programs.

What we know about placenta accreta spectrum (PAS)

Placenta accreta spectrum (PAS) is an umbrella term for a variety of pregnancy complications due to abnormal placental implantation, including placenta accreta, placenta increta and placenta percreta. During the past several decades, the prevalence of PAS has been increasing, and the clinical importance of this disease is significant because of the severe complications. In this review, we summarized the available evidence-based data for PAS in various aspects: prevalence, risk factors, pathogenesis, clinical presentation and prenatal screening, and clinical management. Meanwhile, we provided a series of prospects in each section for further studies on PAS. Moreover, we first present a visualized workflow for the management of PAS from three steps: predelivery, during delivery and postdelivery.

Maternal morbidity in placenta accreta spectrum following introduction of a multi-disciplinary service compared to standard care: an Irish perspective

AIM

The purpose of this study is to compare maternal outcomes in patients with placenta accreta spectrum (PAS) when managed as part of a multi-disciplinary team (MDT) compared to standard care.

METHODS

Patients in the standard care group were retrospectively identified from pathology records, with patients in the MDT group prospectively collected on an electronic database. Data on maternal demographics, delivery, estimated blood loss (EBL), transfusion requirements, and morbidity were recorded.

RESULTS

Sixty patients were diagnosed with PAS between 2006 and 2019, of whom 32 were part of the standard care group and 28 in the MDT group. Compared to standard care, MDT care was associated with an increase in antenatal diagnosis from 56.3 to 92.9% (p < 0.0001), a significant reduction in EBL (4150 mL (800-19500) vs 1975 (495-8500), p < 0.0001), and transfusion requirements (median 7 (0-30) units of RCC vs 1 (0-13), p < 0.0001).

CONCLUSION

PAS is associated with significant maternal morbidity and warrants management in an MDT setting with specialist input, which is associated with improved outcomes.

Effectiveness of contingent screening for placenta accreta spectrum disorders based on persistent low-lying placenta and previous uterine surgery

OBJECTIVES

Maternal mortality related to placenta accreta spectrum (PAS) disorders remains substantial when diagnosed unexpectedly at delivery. The aim of this study was to evaluate the effectiveness of a routine contingent ultrasound screening program for PAS.

METHODS

This was a retrospective study of data obtained between 2009 and 2019, involving two groups: a screening cohort of unselected women attending for routine mid-trimester ultrasound assessment and a diagnostic cohort consisting of women referred to the PAS diagnostic service with a suspected diagnosis of PAS. In the screening cohort, women with a low-lying placenta at the mid-trimester assessment were followed up in the third trimester, and those with a persistent low-lying placenta (i.e. placenta previa) and previous uterine surgery were referred to the PAS diagnostic service. Ultrasound assessment by the PAS diagnostic service consisted of two-dimensional grayscale and color Doppler ultrasonography, and women with a diagnosis of PAS were usually managed with conservative myometrial resection. The final diagnosis of PAS was based on a combination of intraoperative clinical findings and histopathological examination of the surgical specimen.

RESULTS

In total, 57 179 women underwent routine mid-trimester fetal anatomy assessment, of whom 220 (0.4%) had a third-trimester diagnosis of placenta previa. Seventy-five of these women were referred to the PAS diagnostic service because of a history of uterine surgery, and 21 of 22 cases of PAS were diagnosed correctly (sensitivity, 95.45% (95% CI, 77.16-99.88%) and specificity, 100% (95% CI, 99.07-100%)). Univariate analysis demonstrated that parity ≥ 2 (odds ratio (OR), 35.50 (95% CI, 6.90-649.00)), two or more previous Cesarean sections (OR, 94.20 (95% CI, 22.00-656.00)) and placenta previa (OR, 20.50 (95% CI, 4.22-369.00)) were the strongest risk factors for PAS. In the diagnostic cohort, there were 173 referrals, with one false-positive and three false-negative diagnoses, resulting in a sensitivity of 96.63% (95% CI, 90.46-99.30%) and a specificity of 98.81% (95% CI, 93.54-99.97%).

CONCLUSIONS

A contingent screening strategy for PAS is both feasible and effective in a routine healthcare setting. When linked to a PAS diagnostic and surgical management service, adoption of such a screening strategy has the potential to reduce the maternal morbidity and mortality associated with this condition. However, larger prospective studies are necessary before implementing this screening strategy 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.

Placenta accreta spectrum disorders-experience of management in a German tertiary perinatal centre

PURPOSE

Placenta accreta spectrum (PAS) disorders can cause major intrapartum haemorrhage. The optimal management approach is not yet defined. We analysed available cases from a tertiary perinatal centre to compare the outcome of different individual management strategies.

METHODS

A monocentric retrospective analysis was performed in patients with clinically confirmed diagnosis of PAS between 07/2012 and 12/2019. Electronic patient and ultrasound databases were examined for perinatal findings, peripartum morbidity including blood loss and management approaches such as (1) vaginal delivery and curettage, (2) caesarean section with placental removal versus left in situ and (3) planned, immediate or delayed hysterectomy.

RESULTS

46 cases were identified with an incidence of 2.49 per 1000 births. Median diagnosis of placenta accreta (56%), increta (39%) or percreta (4%) was made in 35 weeks of gestation. Prenatal detection rate was 33% for all cases and 78% for placenta increta. 33% showed an association with placenta praevia, 41% with previous caesarean section and 52% with previous curettage. Caesarean section rate was 65% and hysterectomy rate 39%. In 9% of the cases, the placenta primarily remained in situ. 54% of patients required blood transfusion. Blood loss did not differ between cases with versus without prenatal diagnosis (p = 0.327). In known cases, an attempt to remove the placenta did not show impact on blood loss (p = 0.417).

CONCLUSION

PAS should be managed in an optimal setting and with a well-coordinated team. Experience with different approaches should be proven in prospective multicentre studies to prepare recommendations for expected and unexpected need for management.

Maternal Serum VEGF Predicts Abnormally Invasive Placenta Better than NT-proBNP: a Multicenter Case-Control Study

The aim of this study was to test if maternal serum vascular endothelial growth factor (VEGF) or N-terminal pro B-type natriuretic peptide (NT-proBNP) predicts abnormally invasive placenta (AIP) better. Secondary objective was to test whether the serum levels of VEGF and NT-proBNP can predict the degree of invasion. In a multicenter case–control study design, gestational age-matched serum samples from pregnant women with AIP (n = 44) and uncomplicated pregnancies (n = 55) who had been enrolled at Charité – Universitätsmedizin Berlin, Germany and Centre Hospitalier Régional de la Citadelle in Liège, Belgium were analyzed. Maternal blood serum VEGF and NT-proBNP levels were immunoassayed from samples taken immediately before delivery (GA median: 35 weeks). Biomarker levels were compared between AIP and control group. The correlation of biomarker levels with the clinical AIP degree was assessed. The predictive biomarker ability was characterized through a multivariate regression model and receiver operating characteristic curves. Women with AIP had significantly lower maternal serum VEGF levels (AIP mean 285 pg/ml, 95% CI 248–322, vs. control: 391 pg/ml, 95% CI 356–426, p < 0.01) and higher NT-proBNP levels (AIP median 329 pg/ml, IQR 287–385, vs. control 295 pg/ml, IQR 273–356, p = 0.03). Maternal serum VEGF levels were able to predict AIP better (AUC = 0.729, 0.622–0.836, p < 0.001; VEGF + number of previous cesarean deliveries: AUC = 0.915, 0.853–0.977, p < 0.001). Maternal serum VEGF levels correlated inversely with the clinical AIP degree (r = − 0.32, p < 0.01). In short, maternal serum VEGF, more than NT-proBNP, can help in predicting AIP and hints at the degree of invasion.

Minimizing surgical blood loss at cesarean hysterectomy for placenta previa with evidence of placenta increta or placenta percreta: the state of play in 2020

The evolution of multidisciplinary team-based care for women with placenta accreta spectrum disorder has delivered stepwise improvements in clinical outcomes. Central to this overall goal is the ability to limit blood loss at surgery. Placement of inflatable balloons within the pelvic arteries, most commonly in the anterior divisions of the internal iliac arteries, became popular in many centers, at the expense of prolonging surgical care and with attendant risks of vascular injury. In tandem, the need to expose pelvic sidewall anatomy to safely identify the course of the ureters re-popularized the alternative strategy of ligating the same anterior divisions of the internal iliac arteries. With incremental gains in surgical expertise, described in 5 steps in this review, our teams have witnessed a steady decline in surgical blood loss. Nevertheless, a subset of women has the most severe form of placenta accreta spectrum, namely placenta previa-percreta. Such women are at risk of major hemorrhage during surgery from vessels arising outside the territories of the internal iliac arteries. These additional blood supplies, mostly from the external iliac arteries, pose significant risks of major blood loss even in experienced hands. To address this risk, some centers, principally in China, have adopted an approach of routinely placing an infrarenal aortic balloon, with both impressively low rates of blood loss and an ability to conserve the uterus by resecting the placenta with the affected portion of the uterine wall. We review these literature developments in the context of safely performing elective cesarean hysterectomy for placenta previa-percreta, the most severe placenta accreta spectrum disorder.

Clinical characteristics and perinatal outcomes of eight cases of umbilical cord vascular rupture

Objectives

To analyze the clinical characteristics and perinatal outcomes of umbilical cord vascular rupture, and to investigate the diagnosis and treatment strategies for reducing adverse perinatal outcomes.

Methods

Clinical data of patients with a singleton pregnancy with umbilical cord rupture who were admitted to Fujian Maternity and Child Health Hospital were collected. The incidence, related factors, clinical features and perinatal outcomes of umbilical cord rupture were retrospectively analyzed.

Results

There were eight cases of umbilical cord rupture (incidence rate: 1/8370). Among them, seven were secondary to umbilical cord insertion abnormality, and one may have been related to a relatively short umbilical cord and umbilical cord traction. There were eight cases of abnormal fetal heart rate, two of vaginal bleeding, five of bloody amniotic fluid, five of premature rupture of the membranes, and two of placental abruption. With regard to outcomes, 50% of patients had cesarean section, 12.5% had forceps delivery, and 50% had perinatal mortality.

Conclusions

Vaginal bleeding, amniotic fluid, fetal heart rate, and umbilical cord insertion should be closely monitored in pregnancy. When abnormal conditions occur, obstetricians should be aware of rupture of the umbilical vessels and terminate pregnancy as soon as possible, which could improve perinatal outcomes.

Uterine body placenta accreta spectrum: A detailed literature review

Placenta accreta spectrum (PAS) is a major obstetrical problem whose incidence is rising. Current guidelines recommend screening of all women with placenta previa and risk factors for PAS between 20 and 24 weeks. Risk factors, diagnosis, and management of previa PAS are well established, but an apparently normal location of the placenta does not exclude PAS. Literature data are scarce on uterine body PAS, which carries a high risk of maternal and neonatal adverse outcome, but is still easily missed on prenatal ultrasound. We conducted a comprehensive review to identify possible risk factors, clinical presentations, and diagnostic modalities of uterine PAS. A total of 133 cases were found during a 70-year period (1949-2019). The vast majority of them presented with signs of uterine rupture, even prior to the viability threshold of 24 weeks (up to 45%). Major risk factors included previous cesarean delivery, uterine curettage, uterine surgery, Asherman's syndrome, manual removal of the placenta, endometritis, high parity, young maternal age, in vitro fertilization, radiotherapy, uterine artery embolization, and uterine leiomyoma. Diagnosis was pre-symptomatic in only 3% of cases. Future studies should differentiate between previa PAS and uterine body PAS.

Vasa previa and associated risk factors: a systematic review and meta-analysis

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.

A Radiologist's Guide to the Performance and Interpretation of Obstetric Doppler US

Doppler US provides a unique window to the fetoplacental circulation, allowing assessment of fetal well-being. Doppler US of the umbilical artery is an integral component of managing the fetus with growth restriction; and Doppler US of the middle cerebral artery, as a noninvasive means of detecting fetal anemia, has revolutionized the management of pregnancies complicated by alloimmunization. Serial use of amniocentesis, with its attendant risks, has been replaced by serial Doppler US examinations. Invasive procedures are now reserved for the treatment of anemia with intrauterine transfusion. Technique is critical to obtain the best waveforms for ease of shape assessment, velocity measurement, and calculation of various ratios. In this article, the safety of Doppler US is reviewed, the fetal circulation is described, and the role of Doppler US is demonstrated in first-trimester screening and in the evaluation of growth restriction, anemia, and other causes of fetal compromise in the second and third trimesters. Sampling technique is explained, and normal and abnormal waveforms are illustrated for the ductus venosus, umbilical artery, umbilical vein, middle cerebral artery, and uterine artery. Some examples of clinical cases are provided to illustrate how the results are used in clinical practice. Clinical examples of velamentous insertion and vasa previa are also provided to aid the practicing radiologist with recognition of these entities. In particular, vasa previa is considered a critical finding; it alters pregnancy management, requiring hospital admission, administration of steroid therapy, and planned early cesarean delivery. ^©RSNA, 2019.

Nonfetal Imaging During Pregnancy: Placental Disease

Placenta is a vital organ that connects the maternal and fetal circulations, allowing exchange of nutrients and gases between the two. In addition to the fetus, placenta is a key component to evaluate during any imaging performed during pregnancy. The most common disease processes involving the placenta include placenta accreta spectrum disorders and placental masses. Several systemic processes such as infection and fetal hydrops can too affect the placenta; however, their imaging features are nonspecific such as placental thickening, heterogeneity, and calcifications. Ultrasound is the first line of imaging during pregnancy, and MR imaging is reserved for problem solving, when there is need for higher anatomic resolution.

Vasa previa: a multicenter retrospective cohort study

OBJECTIVE

The objective of the study was to describe the characteristics and outcomes of patients with antenatal diagnosis of vasa previa and evaluate the predictive factors of resolution in a contemporary large, multicenter data set.

STUDY DESIGN

This was a retrospective multicenter cohort study of all antenatally diagnosed cases of vasa previa, identified via ultrasound and electronic medical record, between January 2011 and July 2018 in 5 US centers. Records were abstracted to obtain variables at diagnosis, throughout pregnancy, and outcomes, including maternal and neonatal variables. Data were reported as median [range] or n (percentage). Descriptive statistics, receiver-operating characteristics, and logistic regression analysis were used as appropriate.

RESULTS

One hundred thirty-six cases of vasa previa were identified in 5 centers during the study period, 19 (14%) of which resolved spontaneously at median estimated gestational age of 27 weeks [19-34]. All subjects with unresolved vasa previa underwent cesarean delivery at a median estimated gestational age of 34 weeks [27-39] with the median estimated blood loss of 800 mL [250-2000]. Rates for vaginal bleeding, preterm labor, premature rupture of membrane, and need for blood product transfusion were not different between the resolved and unresolved group (P = NS). The odds ratio for resolution in those with the estimated gestational age of less than 24 weeks at the time of diagnosis was 7.9 (95% confidence interval, 2.1-29.4) after adjustment for confounding variables.

CONCLUSION

Our data suggest that outcomes in antenatally diagnosed cases of vasa previa are excellent. Furthermore, our data report a higher chance of resolution when the condition is diagnosed before 24 weeks of gestation.

New evidence-based diagnostic and management strategies for placenta accreta spectrum disorders

The increasing incidence of caesarean delivery (CD) has resulted in an increase in placenta accreta spectrum (PAS), adversely impacting maternal outcomes globally. Currently, more than 90% of women diagnosed with PAS present with a placenta praevia (praevia PAS). Praevia PAS can be reliably diagnosed antenatally with ultrasound, and it is unclear whether magnetic resonance imaging improves diagnosis beyond what can be achieved by skilled ultrasound operators. Therefore, any screening programme for PAS will require improved training in the diagnosis of placental disorders and development of targeted scanning protocols. Management strategies for praevia PAS vary depending on the accuracy of prenatal diagnosis, findings at laparotomy and local surgical expertise. Current epidemiological data for PAS are highly heterogeneous, mainly due to wide variation in the clinical criteria used to diagnose the condition at birth. This significantly impacts research into all aspects of the condition, especially comparison of the efficacy of different management strategies.

First trimester ultrasound prediction of velamentous cord insertions: a prospective study

INTRODUCTION

The marginal and velamentous cord insertions complicate around 8% of pregnancies and are at higher risk of adverse perinatal outcomes. Their visualisation seems to decrease with advancing gestational age. Our aim was to analyse whether an umbilical cord insertion in the lower third of the uterus during the first trimester could predict abnormal cord insertions later in pregnancy.

METHODS

This was a prospective multicentre study in two hospitals. During the first trimester, the cord insertions were inspected as well as their location (lower third of the uterus or not). Finally, all cord insertions were described at delivery.

RESULTS

During the study period the cord insertion was described in 1620 patients of which 87.7% had a normal cord insertion, 11.9% (n = 192) a low cord insertion, and in 3.8% the insertion could not be situated. We find that 4.7% of those who have a low-lying cord insertion versus 0.7% in the normal cord insertion group during the first trimester will have a velamentous cord insertion subsequently (OR = 6.67; 95% CI = 2.67-16.63).

CONCLUSION

The detection of a low lying umbilical cord insertion during the first-trimester ultrasound can help to predict an abnormal cord insertion at delivery particularly a velamentous cord insertion.

Association of Implementing a Multidisciplinary Team Approach in the Management of Morbidly Adherent Placenta With Maternal Morbidity and Mortality

OBJECTIVE

To compare maternal outcomes in patients with morbidly adherent placenta managed in a multidisciplinary team setting compared with standard care.

DATA SOURCES

A literature search was performed for publications reporting multidisciplinary pathways in the management of cesarean delivery for patients with morbidly adherent placenta. EMBASE, MEDLINE, PubMed, PubMed Central, ClinicalTrials.gov, and Cochrane databases were searched.

METHODS OF STUDY SELECTION

Databases were searched for studies reporting maternal morbidity of patients with morbidly adherent placenta managed by a multidisciplinary team in a specialist center compared with standard care. Two independent reviewers applied inclusion and exclusion criteria to select included articles, with differences agreed by consensus. A total of 252 citations were reviewed; six studies comprising 461 patients were selected for the analysis.

TABULATION, INTEGRATION, AND RESULTS

Literature search was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results were reported as mean differences or pooled odds ratios (ORs) with 95% CIs. Estimated blood loss was significantly reduced in the multidisciplinary team group (mean difference -1.1 L, 95% CI -1.9 to -0.4, P=.004) and these patients had lower transfusion requirements (mean difference -2.7 units, 95% CI -4.1 to -1.2, P=.040). Those treated in a standard care setting were more likely to develop complications (OR 2.5, 95% CI 1.5-4.0, P<.001); however, there was no difference in length of stay between the two groups.

CONCLUSION

This meta-analysis highlights the improved maternal outcomes in patients with morbidly adherent placenta when managed by a multidisciplinary team in a specialist center. High-risk complex cases warrant expert management in centralized units.

Vasa previa: prenatal diagnosis and management

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.

Persistent hypoxia induced autophagy leading to invasiveness of trophoblasts in placenta accreta

BACKGROUND

Excessive trophoblasts erosivity is the main pathological manifestation in placenta accreta. Similar to early pregnancy, trophoblasts of placenta accreta might have a similar anoxic state in abnormal continuous invasion, in which autophagy may also have some changes causing invasive ability in accreta.

METHODS

Ten accreta placentas (placenta accreta group), as well as 10 non-accreta placentas (control group), were collected according to accreta criteria. The expression of hypoxia-induced autophage factors (HIF1α, Beclin 1, LC3B, and P62) and invasion-related markers (E-cadherin and MMP-9) were detected using immunohistochemical method. Comparison in scores grade was made between the two groups by Fisher's exact test and Spearman's test was used for correlation analysis.

RESULTS

HIF1α was mainly expressed in cytomembrane of trophoblasts, in which moderate positive 50% (5/10) and strong positive 50% (5/10) in placenta accreta group compared to 50% (5/10) or weak positive 30% (3/10) in control group, with a significant statistically difference (p < .05). The negative, weak positive, moderate positive, and strong positive rates of Beclin-1 expression were 0, 10, 30, and 60% versus 60, 40, 0, and 0% in placenta accreta group and control group, respectively, statistically different (p < .05). The expression of LC3B was also statistically significant (0, 10, 20, 70% versus 50, 20, 30, 0%) between two groups, and P62 expression was also statistically different between two groups. The positive rates of E-cadherin expression were obviously negatively correlated with Beclin-1, LC3B, and P62 expression, while positive rates of MMP-9 expression were positively correlated with autophagy-associated markers.

CONCLUSIONS

Hypoxia state might be involved in the occurrence of placental accreta, and persistent hypoxia state induced autophage disorders could cause down-regulated E-cadherin and down-regulated MMP-9, thus leading to more invasiveness of placenta trophoblasts.

Term cesarean delivery in the first pregnancy is not associated with an increased risk for preterm delivery in the subsequent pregnancy

BACKGROUND

Prior studies have reported an increased risk for preterm delivery following a term cesarean delivery. However, these studies did not adjust for high-risk conditions related to the first cesarean delivery and are known to recur.

OBJECTIVE

The objective of the study was to determine whether there is an association between term cesarean delivery in the first pregnancy and subsequent spontaneous or indicated preterm delivery.

STUDY DESIGN

This was a retrospective cohort study of women with the first 2 consecutive singleton deliveries (2007-2014) identified through a linked pregnancy database at a single institution. Women with a first pregnancy that resulted in cesarean delivery at term were compared with women whose first pregnancy resulted in a vaginal delivery at term. Exclusion criteria were known to recur medical or obstetrical complications during the first pregnancy. A propensity score analysis was performed by matching women who underwent a cesarean delivery with those who underwent a vaginal delivery in the first pregnancy. The association between cesarean delivery in the first pregnancy and preterm delivery in the second pregnancy in this matched set was examined using conditional logistic regression. The primary outcome was overall preterm delivery <37 weeks in the second pregnancy. Secondary outcomes included type of preterm delivery (spontaneous vs indicated), late preterm delivery (34-36 6/7 weeks), early preterm delivery (<34 weeks), and small-for-gestational-age birth.

RESULTS

Of a total of 6456 linked pregnancies, 2284 deliveries were matched; 1142 were preceded by cesarean delivery and 1142 were preceded by vaginal delivery. The main indications for cesarean delivery in the first pregnancy were dystocia in 703 (61.5%), nonreassuring fetal status in 222 (19.4%), breech presentation in 100 (8.8%), and other in 84 (7.4%). The mean (SD) gestational ages at delivery for the second pregnancy was 38.8 (1.8) and 38.9 (1.7) weeks, respectively, for prior cesarean delivery and vaginal delivery. The risks of preterm delivery in the second pregnancy among women with a previous cesarean and vaginal delivery were 6.0% and 5.2%, respectively (adjusted odds ratio, 1.46, 95% confidence interval, [CI] 0.77-2.76). In an analysis stratified by the type of preterm delivery in the second pregnancy, no associations were seen between cesarean delivery in the first pregnancy and spontaneous preterm delivery (4.6% vs 3.9%; adjusted odds ratio, 1.40, 95% confidence interval, 0.59-3.32) or indicated preterm delivery (1.6% vs 1.4%; adjusted odds ratio, 1.21, 95% confidence interval, 0.60-2.46). Similarly, no significant differences were found in late preterm delivery (4.6% vs 4.1%; adjusted odds ratio, 1.13, 95% confidence interval, 0.55-2.29), early preterm delivery (1.6% vs 1.2%; adjusted odds ratio, 1.25, 95% confidence interval, 0.59-2.67), or neonates with birthweight less than the fifth percentile for gestational age (3.6% vs 2.2%; adjusted odds ratio, 1.26, 95% confidence interval, 0.52-3.06).

CONCLUSION

After robust adjustment for confounders through a propensity score analysis related to the indication for the first cesarean delivery at term, cesarean delivery is not associated with an increase in preterm delivery, spontaneous or indicated, in the subsequent pregnancy.