Placenta accreta spectrum disorders clinical practice guidelines: A systematic review

Duration time of labor progression for pregnant women of vaginal birth after cesarean in Hubei, China

OBJECTIVE

There have been limited reports on the duration of labor progression in pregnant women undergoing vaginal birth after cesarean (VBAC). This study aimed to investigate the duration of labor progression during VBAC in Hubei, China.

METHODS

A total of 359 pregnant women undergoing VBAC were enrolled as the VBAC group, meeting the following criteria: singleton pregnancy, gestational age ≥ 37 weeks, live birth, history of cesarean delivery, and a willingness to attempt a vaginal delivery. At the same time, 359 primiparas successfully undergoing vaginal delivery were randomly enrolled in the control group at a 1:1 ratio. Subsequently, the durations of the first, second, and third stages of labor were comparatively analyzed between the two groups.

RESULTS

The duration of the first, second, and total stages of labor in the VBAC group was significantly shorter than that in the control group (p < 0.05). There was no significant difference in the duration of the third stage of labor between the two groups (p > 0.05). The amount of blood loss, the rate of postpartum hemorrhage (PPH), and episiotomy were higher in the VBAC group than in the control group (p < 0.05). The rate of labor analgesia and intrapartum fever in the VBAC group was significantly lower than that in the control group (p < 0.05).

CONCLUSION

The duration of labor progression of the first, second, and total stages of VBAC is shorter than that in primiparous women in our observation in China.

Quality evaluation of clinical practice guidelines for placenta accreta spectrum disorders

Introduction

We evaluated the quality of the published clinical practice guidelines on placenta accreta spectrum (PAS) disorders to provide reference for the development of high-quality PAS guidelines.

Methods

China National Knowledge Infrastructure (CNKI), Wan Fang, PubMed, Embase, Web of Science, and Cochrane Library were systematically searched. Quality assessments were conducted using the appraisal of guidelines for research and evaluation (AGREE) II framework and Reporting Items for practice Guidelines in Healthcare (RIGHT) checklist. Intraclass correlation coefficients (ICCs) were used to measure the agreement among reviewers.

Results

In total, 13 guidelines from different countries, published between 2015 and 2021 were included. There included 9 official guidelines, 3 consensuses, and 1 standard reference and covered subjects including epidemiology, diagnosis and treatment. The mean standardized scores across 6 domains (scope and purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability, and editorial independence) were 53.63%, 27.35%, 33.57%, 72.01%, 19.39% and 41.02%, respectively. Of the 13 guidelines, 11 were classified as grade B, whereas 2 as grade C. According to the RIGHT checklist, the overall reporting rate of the 13 guidelines ranged from 28.57% to 54.29%.

Conclusion

The current guidelines for PAS demonstrate commendable methodological and reporting qualities. However, the methodological and reporting quality of PAS CPGs still need to be further improved, particularly in stakeholder involvement, the rigor of development, applicability, and editorial independence domains.

Deep Learning Radiomic Analysis of MRI Combined with Clinical Characteristics Diagnoses Placenta Accreta Spectrum and its Subtypes

BACKGROUND

Different placenta accreta spectrum (PAS) subtypes pose varying surgical risks to the parturient. Machine learning model has the potential to diagnose PAS disorder.

PURPOSE

To develop a cascaded deep semantic-radiomic-clinical (DRC) model for diagnosing PAS and its subtypes based on T2-weighted MRI.

STUDY TYPE

Retrospective.

POPULATION

361 pregnant women (mean age: 33.10 ± 4.37 years), suspected of PAS, divided into segment training cohort (N = 40), internal training cohort (N = 139), internal testing cohort (N = 60), and external testing cohort (N = 122).

FIELD STRENGTH/SEQUENCE

Coronal T2-weighted sequence at 1.5 T and 3.0 T.

ASSESSMENT

Clinical characteristics such as history of uterine surgery and the presence of placenta previa, complete placenta previa and dangerous placenta previa were extracted from clinical records. The DRC model (incorporating radiomics, deep semantic features, and clinical characteristics), a cumulative radiological score method performed by radiologists, and other models (including a radiomics and clinical, the clinical, radiomics and deep learning models) were developed for PAS disorder diagnosing (existence of PAS and its subtypes).

STATISTICAL TESTS

AUC, ACC, Student's t-test, the Mann-Whitney U test, chi-squared test, dice coefficient, intraclass correlation coefficients, least absolute shrinkage and selection operator regression, receiver operating characteristic curve, calibration curve with the Hosmer-Lemeshow test, decision curve analysis, DeLong test, and McNemar test. P < 0.05 indicated a significant difference.

RESULTS

In PAS diagnosis, the DRC-1 outperformed than other models (AUC = 0.850 and 0.841 in internal and external testing cohorts, respectively). In PAS subtype classification (abnormal adherent placenta and abnormal invasive placenta), DRC-2 model performed similarly with radiologists (P = 0.773 and 0.579 in the internal testing cohort and P = 0.429 and 0.874 in the external testing cohort, respectively).

DATA CONCLUSION

The DRC model offers efficiency and high diagnostic sensitivity in diagnosis, aiding in surgical planning.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

MRI-Based Risk Factors for Adverse Maternal Outcomes in Prophylactic Aortic Balloon Occlusion for Placenta Accreta Spectrum and Placenta Previa

PURPOSE

We previously reported that T2 dark bands and placental bulges observed in magnetic resonance imaging (MRI) can predict adverse maternal outcomes in patients with placenta accreta spectrum (PAS) and placenta previa undergoing prophylactic balloon occlusion of the internal iliac artery. On the other hand, the risk factors associated with the use of prophylactic aortic balloon occlusion (PABO) have not been sufficiently investigated. This retrospective study aimed to identify MRI-based risk factors associated with adverse maternal outcomes in the context of PABO during a cesarean section (CS) for PAS and placenta previa.

MATERIALS AND METHODS

Ethical approval was obtained for a data analysis of 40 patients diagnosed with PAS and placenta previa undergoing PABO during a CS. Clinical records, MRI features, and procedural details were examined. The inclusion criteria for the massive bleeding group were as follows: an estimated blood loss (EBL) > 2500 mL, packed red blood cell (pRBC) transfusion (>4 units), and the need for a hysterectomy or transcatheter arterial embolization after delivery. The massive and nonmassive bleeding groups were compared.

RESULTS

Among the 22 patients, those in the massive bleeding group showed significantly longer operative durations, a higher EBL (p < 0.001), an increased number of pRBC transfusions (p < 0.001), and prolonged postoperative hospital stays (p < 0.05). T2 dark bands on MRI were significant predictors of adverse outcomes (p < 0.05).

CONCLUSION

T2 dark bands on MRI were crucial predictors of adverse maternal outcomes in patients undergoing PABO for PAS or placenta previa during a CS. Recognizing these MRI features proactively indicates the need for effective management strategies during childbirth and emphasizes the importance of further prospective studies to validate and enhance these findings.

Determinants of emergency Cesarean delivery in pregnancies complicated by placenta previa with or without placenta accreta spectrum disorder: analysis of ADoPAD cohort

OBJECTIVES

To investigate the rate and outcome of emergency Cesarean delivery (CD) in women with placenta previa with or without placenta accreta spectrum disorders (PAS) and to elucidate the diagnostic accuracy of ultrasound in predicting emergency CD.

METHODS

This was a secondary analysis of a multicenter prospective study involving 16 referral hospitals in Italy (ADoPAD study). Inclusion criteria were women with placenta previa minor (< 20 mm from the internal cervical os) or placenta previa major (covering the os), aged ≥ 18 years, who underwent transabdominal and transvaginal ultrasound assessment at ≥ 26 + 0 weeks of gestation. The primary outcome was the occurrence of emergency CD, defined as the need for immediate surgical intervention performed for emergency maternal or fetal indication, including active labor, cumulative maternal bleeding > 500 mL, severe and persistent vaginal bleeding such that maternal hemodynamic stability could not be achieved or maintained, or category-III fetal heart rate tracing unresponsive to resuscitative measures. The primary outcome was reported separately in the population of women with placenta previa and no PAS confirmed after birth and in those with PAS. The secondary aim was to report on the strength of association and to test the diagnostic accuracy of ultrasound in predicting emergency CD. Univariate, multivariate and diagnostic accuracy analyses were used to analyze the data.

RESULTS

A total of 450 women, including 97 women with placenta previa and PAS and 353 with placenta previa only, were analyzed. In women with placenta previa and PAS, emergency CD was required in 20.6% (95% CI, 14-30%), and 60.0% (12/20) delivered before 34 weeks of gestation. The mean gestational age at delivery was 32.3 ± 2.7 weeks in women undergoing emergency CD and 34.9 ± 1.8 weeks in those undergoing elective CD (P < 0.001). Women undergoing emergency CD had a higher median estimated blood loss (2500 (interquartile range (IQR), 1350-4500) vs 1100 (IQR, 625-2500) mL; P = 0.012), mean units of blood transfused (7.3 ± 8.8 vs 2.5 ± 3.4; P = 0.02) and more frequent placement of a mechanical balloon (50.0% vs 16.9%; P = 0.002) compared with those undergoing elective CD. On univariate analysis, the presence of interrupted retroplacental space, interrupted bladder line and placental lacunae was more common in women not experiencing emergency CD. No comprehensive multivariate analysis could be performed in this subgroup of women. Ultrasound signs of PAS, including presence of interrupted retroplacental space, interrupted bladder line and placental lacunae, were not predictive of emergency CD. In women with placenta previa but no PAS, emergency CD was required in 31.2% (95% CI, 26.6-36.2%), and 32.7% (36/110) delivered before 34 weeks of gestation. The mean gestational age at delivery was lower in women undergoing emergency CD compared with those undergoing elective CD (34.2 ± 2.9 vs 36.7 ± 1.6 weeks; P < 0.001). Pregnancies complicated by emergency CD were associated with a lower birth weight (2330 ± 620 vs 2800 ± 480 g; P < 0.001) and had a higher risk of need for blood transfusion (22.7% vs 10.7%; P = 0.003) compared with those who underwent elective CD. On multivariate analysis, only placental thickness (odds ratio (OR), 1.02 (95% CI, 1.00-1.03); P = 0.046) and cervical length < 25 mm (OR, 3.89 (95% CI, 1.33-11.33); P = 0.01) were associated with emergency CD. However, a short cervical length showed low diagnostic accuracy for predicting emergency CD in these women.

CONCLUSION

Emergency CD occurred in about 20% of women with placenta previa and PAS and 30% of those with placenta previa only and was associated with worse maternal outcome compared with elective intervention. Prenatal ultrasound is not predictive of the risk of emergency CD in women with these disorders. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Termination of a second-trimester pregnancy with placenta accreta spectrum disorder

Background: The termination of pregnancy in patients with placenta accreta spectrum disorder (PASD) during the second trimester remains uncertain. In addition, interventional radiology techniques, such as arterial embolization and balloon placement, are potential options. We evaluated the outcomes of pregnancy termination in patients with PASD during the second trimester and the effectiveness of preoperative interventional radiology techniques.Methods: This retrospective study analyzed 48 PASD patients who underwent pregnancy termination during the second trimester between January 2016 and May 2021.Results: Of the 48 patients, 20 (41.67%) underwent transvaginal termination, whereas 28 (58.33%) underwent cesarean section. Notably, no significant differences were observed in success rates between the transvaginal termination and cesarean section groups (80.00% vs. 92.86%, P = 0.38). Furthermore, no statistically significant differences were observed in the success rates (94.12% vs 90.32%, P = 1.00) and blood loss (512.35 ± 727.00 ml vs 804.00 ± 838.98 ml, P = 0.23) between the artery embolization and non-embolization groups. In the vaginal termination group, statistically significant differences were observed in gestational weeks (16.70 ± 3.12 vs 22.67 ± 3.63, P < 0.01) and blood loss (165.00 ± 274.43 ml vs 483.64 ± 333.53 ml, P = 0.04) between the (artery embolization and non-embolization) subgroups. Conversely, in the cesarean section group, no significant differences were observed in gestational weeks (23.59 ± 3.14 vs 23.20 ± 4.37, P = 0.79) and blood loss (811.11 ± 879.55 ml vs 989.47 ± 986.52 ml, P = 0.76) between the subgroups.Conclusions: Further studies are needed to evaluate the efficacy of vaginal termination in PASD patients during the second trimester. Regarding cesarean termination, arterial embolization did not demonstrate increased effectiveness.

Urological complications in women undergoing Cesarean section for placenta accreta spectrum disorders: systematic review and meta-analysis

OBJECTIVE

To report on the occurrence of urological complications in women undergoing Cesarean section for placenta accreta spectrum disorders (PAS).

METHODS

MEDLINE, EMBASE and the Cochrane databases were searched electronically up to 1 November 2022. Studies reporting on the urological outcome of women undergoing Cesarean section for PAS were included. Two independent reviewers performed data extraction using a predefined protocol and assessed the risk of bias using the Newcastle-Ottawa scale for observational studies, with disagreements resolved by consensus.The primary outcome was the overall occurrence of urological complications. Secondary outcomes were the occurrence of any cystotomy, intentional cystotomy, unintentional cystotomy, ureteral damage, ureteral fistula and vesicovaginal fistula. All outcomes were explored in the overall population of women undergoing surgery for PAS. In addition, we performed subgroup analyses according to the type of surgery (Cesarean hysterectomy, or conservative surgery or management), severity of PAS at histopathology (placenta accreta/increta and placenta percreta), type of intervention (planned vs emergency) and number of cases per year. Random-effects meta-analyses of proportions were used to analyze the data.

RESULTS

There were 62 studies included in the systematic review and 56 were included in the meta-analysis. Urological complications occurred in 15.2% (95% CI, 12.9-17.7%) of cases. Cystotomy complicated 13.5% (95% CI, 9.7-17.9%) of surgical operations. Intentional cystotomy was required in 7.7% (95% CI, 6.5-9.1%) of cases, while unintentional cystotomy occurred in 7.2% (95% CI, 6.0-8.5%) of cases. Urological complications occurred in 19.4% (95% CI, 16.3-22.7%) of cases undergoing hysterectomy and 12.2% (95% CI, 7.5-17.8%) of those undergoing conservative treatment. In the subgroup analyses, urological complications occurred in 9.4% (95% CI, 5.4-14.4%) of women with placenta accreta/increta and 38.5% (95% CI, 21.6-57.0%) of those described as having placenta percreta, and included mainly cystotomy (5.5% (95% CI, 0.6-15.1%) and 22.0% (95% CI, 5.4-45.5%), respectively). Urological complications occurred in 15.4% (95% CI, 8.1-24.6%) of cases undergoing a planned procedure and 24.6% (95% CI, 13.0-38.5%) of those undergoing an emergency intervention. In subanalysis of studies reporting on ≥ 12 cases per year, the incidence of urological complication was similar to that reported in the primary analysis.

CONCLUSIONS

Women undergoing surgery for PAS are at high risk of urological complication, mainly cystotomy. The incidence of these complications was particularly high in women described as having placenta percreta at birth and in those undergoing emergency surgical intervention. The high heterogeneity between the included studies highlights the need for a standardized protocol for the diagnosis of PAS to identify prenatal imaging signs associated with the increased risk of urological morbidity at delivery. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of placenta accreta spectrum in patients with placenta previa using a clinical, US and MRI combined model: A retrospective study with external validation

PURPOSE

To build and validate a predictive model of placental accreta spectrum (PAS) in patients with placenta previa (PP) combining clinical risk factors (CRF) with US and MRI signs.

METHOD

Our retrospective study included patients with PP from two institutions. All patients underwent US and MRI examinations for suspicion of PAS. CRF consisting of maternal age, cesarean section number, smoking and hypertension were retrieved. US and MRI signs suggestive of PAS were evaluated. Logistic regression analysis was performed to identify CRF and/or US and MRI signs associated with PAS considering histology as the reference standard. A nomogram was created using significant CRF and imaging signs at multivariate analysis, and its diagnostic accuracy was measured using the area under the binomial ROC curve (AUC), and the cut-off point was determined by Youden's J statistic.

RESULTS

A total of 171 patients were enrolled from two institutions. Independent predictors of PAS included in the nomogram were: 1) smoking and number of previous CS among CRF; 2) loss of the retroplacental clear space at US; 3) intraplacental dark bands, focal interruption of the myometrial border and placental bulging at MRI. A PAS-prediction nomogram was built including these parameters and an optimal cut-off of 14.5 points was identified, showing the highest sensitivity (91%) and specificity (88%) with an AUC value of 0.95 (AUC of 0.80 in the external validation cohort).

CONCLUSION

A nomogram-based model combining CRF with US and MRI signs might help to predict PAS in PP patients, with MRI contributing more than US as imaging evaluation.

Upregulated CXCL8 in placenta accreta spectruma regulates the migration and invasion of HTR-8/SVneo cells

BACKGROUND

Placenta accreta spectrum (PAS) is mainly characterized by excessive invasion of the uterine muscle layer accompanied by a large number of foreign blood vessels, leading to severe bleeding during and after delivery. However, the mechanism of excessive invasion of nutrient cells in placenta accreta is currently unclear.

METHODS

We performed RNA sequencing of 6 PAS patients and 4 control donors, coupled with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The mRNA and protein expression of C-X-C motif ligand 8 (CXCL8) in the placental tissue was measured by qRT‒PCR, immunohistochemical staining and Western blotting. HTR-8/SVneo human villous trophoblast Neo cells were used for in vitro investigation of cell migration and invasion as well as the expression level of CXCL8.

RESULTS

A total of 1120 differentially expressed mRNAs were identified in PAS patients. Moreover, GO and KEGG analyses indicated that the differentially expressed mRNAs were most closely associated with immune system processes, biological adhesion and Wnt signaling pathway. The CXCL8 mRNA and protein levels in PAS tissue were significantly higher than those in normal placental tissue. Forced overexpression of CXCL8 significantly increased the migration and invasion of HTR-8/SVneo cells, accompanied by the upregulation of matrix metalloproteinase-2 and matrix metalloproteinase-9 and the downregulation of E-cadherin, which was reversed by knockdown of CXCL8.

CONCLUSIONS

CXCL8 was highly expressed in PAS, and knockdown of CXCL8 suppressed the migration and invasion of HTR-8/SVneo cells, suggesting its potential as a diagnostic and therapeutic target for PAS.

Risk factors of emergency cesarean section in pregnant women with severe placenta accreta spectrum: a retrospective cohort study

Introduction

Placenta accreta spectrum (PAS) may cause enormous and potentially life-threatening hemorrhage in the intrapartum and postpartum periods in emergency cesarean section. How to reduce the occurrence of emergency cesarean section in patients with severe PAS is the key to reducing the adverse outcomes of them. This study aimed to investigate the impact of emergency cesarean section on the perioperative outcomes of pregnant women with PAS and neonates, and also aimed to explore the risk factors of emergency cesarean section in pregnant women with PAS.

Materials and methods

A retrospective investigation was conducted among 163 pregnant women with severe PAS. Of these, 72 were subjected to emergency cesarean sections. Data on the perioperative characteristics of the mothers and neonates were collected. Multivariable linear regression analysis was used to detect associations between maternal and perioperative characteristics and volume of intraoperative bleeding. Binary logical regression was used to analyze the association between maternal preoperative characteristics and emergency cesarean section. Linear regression analysis is used to analyze the relationship between gestational age and emergency cesarean section.

Results

The risks of emergency cesarean section increase 98, 112, 124, and 62% when the pregnant women with PAS accompanied by GHD, ICP, more prior cesarean deliveries and more severe PAS type, respectively. Noteworthy, the risk of emergency cesarean section decreases 5% when pre-pregnancy BMI increases 1 kg/m² (OR: 0.95; CI: 0.82, 0.98; p = 0.038). Moreover, there is no significant linear correlation between emergency cesarean section and gestational age.

Conclusion

GHD, ICP, multiple prior cesarean deliveries and severe PAS type may all increase the risk of emergency cesarean section for pregnant women with PAS, while high pre-pregnancy BMI may be a protective factor due to less activity level. For pregnant women with severe PAS accompanied by these high risk factors, more adequate maternal and fetal monitoring should be carried out in the third trimester to reduce the risk of emergency cesarean section.