BACKGROUND: Placenta accreta spectrum (PAS) disorder is a critical and severe obstetric condition associated with high risk of intraoperative massive hemorrhage and cesarean hysterectomy. Severe obstetric hemorrhage is currently one of the leading causes of maternal death worldwide. Prophylactic balloon occlusions, including prophylactic balloon occlusion of the abdominal aorta (PBOAA) and prophylactic balloon occlusion of the internal iliac arteries (PBOIIA), are the most common means of controlling hemorrhage in patients with PAS disorder, but their effectiveness is still debated.
OBJECTIVE: A systematic review and meta-analysis were conducted to evaluate the clinical effectiveness of prophylactic balloon occlusion during cesarean section (CS) in improving maternal outcomes for PAS patients.
METHODS: MEDLINE, EMBASE, OVID, PubMed and the Cochrane Library were systematically searched from the inception dates to June 2022, using the keywords \"placenta accreta spectrum disorder/morbidly adherent placenta (placenta previa, placenta accreta, placenta increta, placenta percreta), balloon occlusion, internal iliac arteries, abdominal aorta, hemorrhage, hysterectomy, estimated blood loss (EBL), packed red blood cells (PRBCs)\" to identify the systematic reviews or meta-analyses.
METHODS: All articles regarding PAS disorders and including the application of balloon occlusion were included in the screening.
METHODS: Two independent researchers performed the data extraction and assessed study quality. EBL volume and PRBC transfusion volume was regarded as the primary endpoints. Random and fixed effects models were used for the meta-analysis (RRs and 95% CIs), and the Newcastle-Ottawa Scale was used for quality assessments.
RESULTS: Of 429 studies identified, a total of 35 trials involving the application of balloon occlusion for patients with PAS disorder during CS were included. A total of 19 studies involving 935 patients who underwent PBOIIA were included in the PBOIIA group, and 851 patients were included in control 1 group. Ten studies including 428 patients with PAS who underwent PBOAA were allocated to the PBOAA group, and 324 patients without PBOAA were included in control 2 group. Simultaneously, we compared the effect on PBOAA and PBOIIA including seven studies, which referred to 267 cases in the PBOAA group and 313 cases in the PBOIIA group. The results showed that the PBOIIA group had a reduced EBL volume (MD: 342.06 mL, 95% CI: -509.90 to -174.23 mL, I2 = 77%, P < 0.0001) and PRBC volume (MD: -1.57 U, 95% CI: -2.49 to -0.66 U, I2 = 91%, P = 0.0008) than that in control 1 group. With regard to the EBL volume (MD: -926.42 mL, 95% CI: -1437.07 to -415.77 mL, I2 = 96%, P = 0.0004) and PRBC transfusion volume (MD: -2.42 U, 95% CI: -4.25 to -0.59 U, I2 = 99%, P = 0.009) we found significant differences between the PBOAA group and control 2 group. Prophylactic balloon occlusion (PBOAA and PBOIIA) had a significant effect on reducing intraoperative blood loss and blood transfusion volume in patients with PAS. Moreover, PBOAA was more effective than PBOIIA in reducing intraoperative blood loss (MD: -406.63 mL, 95% CI: -754.12 to -59.13 mL, I2 = 92%, P = 0.020), but no significant difference in controlling PRBCs (MD: -3.48 U, 95% CI: -8.90 to 1.95 U, I2 = 99%, P = 0.210) between the PBOIIA group and the PBOAA group. Hierarchical analysis was conducted by differentiating gestational weeks and maternal age to reduce the high heterogeneity of meta-analysis. Hierarchical analysis results demonstrated the heterogeneities of the study were reduced to some extent, and gestational weeks and maternal age might be the cause of increased heterogeneity.
CONCLUSIONS: Prophylactic balloon occlusion is a safe and effective method to control hemorrhage and reduce PRBC transfusion volume for patients with PAS, and PBOAA could reduce more intraoperative blood loss than PBOIIA. However, we found no statistical difference in lessening packed red blood cell transfusion volume for PAS patients. Hence, preoperative prophylactic balloon occlusion is the recommended application for PAS patients in obstetric CSs. Furthermore, PBOAA is preferred for controlling intraoperative bleeding in patients with corresponding medical conditions.

UNASSIGNED: Placenta accreta spectrum (PAS) represents a range of disorders characterized by abnormal placental invasion and is associated with severe maternal morbidity and mortality.
UNASSIGNED: The aim of this study was to review and compare the most recently published major guidelines on the diagnosis and management of this potentially life-threatening obstetric complication.
UNASSIGNED: A descriptive review of guidelines from the American College of Obstetricians and Gynecologists, the Royal Australian and New Zealand College of Obstetricians and Gynecologists, the International Society for Abnormally Invasive Placenta, the Royal College of Obstetricians and Gynecologists, the International Federation of Gynecology and Obstetrics, and the Society of Obstetricians and Gynecologists of Canada on PAS disorders was carried out.
UNASSIGNED: There is a consensus among the reviewed guidelines regarding the definition and the diagnosis of PAS using specific sonographic signs. In addition, they all agree that the use of magnetic resonance imaging should be limited to the evaluation of the extension to pelvic organs in case of placenta percreta. Moreover, American College of Obstetricians and Gynecologists, Royal College of Obstetricians and Gynecologists, International Federation of Gynecology and Obstetrics, and the Society of Obstetricians and Gynecologists of Canada agree that screening for PAS disorders should be based on clinical risk factors along with sonographic findings. Regarding management, they all highlight the importance of a multidisciplinary team approach and recommend delivery by elective cesarean section at a tertiary center with experienced staff and appropriate resources. Routine preoperative ureteric stenting and occlusion of pelvic arteries are universally not recommended. Moreover, hysterectomy following the delivery of the fetus, expectant management with placenta left in situ, and conservative management in case of focal disease and desired fertility are all considered as acceptable treatment options. The reviewed guidelines also suggest some measures for intraoperative and postoperative hemorrhage control and recommend prophylactic administration of antibiotics. Methotrexate after expectant management is unanimously discouraged. On the other hand, there is no common pathway with regard to the optimal timing of delivery, the recommended mode of anesthesia, the preferred skin incision, and the effectiveness of the delayed hysterectomy approach.
UNASSIGNED: PAS disorders are mainly iatrogenic conditions with a constantly rising incidence and potentially devastating consequences for both the mother and the neonate. Thus, the development of uniform international practice protocols for effective screening, diagnosis, and management seems of paramount importance and will hopefully drive favorable pregnancy outcomes.

Our systematic review highlights that multiparametric PAI score assessment is a consistent tool with high sensitivity and specificity for prenatal prediction for placenta accreta spectrum (PAS) in high-risk population with anterior placenta previa or low-lying placenta and prior cesarean deliveries. A systematic search was conducted on November 1, 2022, of MEDLINE via PubMed, Scopus, Web of Science Core Collection, Cochrane Library, and Google Scholar to identify relevant studies (PROSPERO ID # CRD42022368211). A total of 11 articles met our inclusion criteria, representing the data of a total of 1,044 cases. Women with PAS had an increased mean PAI total score, compared to those without PAS. Limitations of the PAI are most studies were conducted in developing countries in high-risk population which limit the global generalizability of findings. Heterogeneity of reported data did not allow to perform meta-analysis.

As birth policy can affect maternal and infant health, we sought to identify whether and how the introduction of the two-child policy might have affected the prevalence of placenta previa in pregnant women in mainland China.
In this update meta-analysis and systematic review, we searched PubMed, Web of Science, the Cochrane Library, Weipu, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases for studies evaluating the prevalence of placenta previa in China published between the inception of each database and March 2024, with no restrictions. Two investigators independently extracted the data from each included study. We then combined the prevalence of placenta previa using random-effects models.
We included 128 studies in our analysis, 48 more than in our previous review. The prevalence of placenta previa among Chinese pregnant women was 1.44% (95% confidence interval (CI) = 1.32, 1.56). After the implementation of the two-child policy, the prevalence increased significantly, from 1.25% (95% CI = 1.16, 1.34) to 4.12% (95% CI = 3.33, 4.91).
The prevalence of placenta previa increased significantly from the one-child policy period to the two-child policy period among mainland Chinese pregnant women, with varying trends across regions. This change requires the attention of health officials and timely adjustment of resource allocation policies.
PROSPERO: CRD42021262309.

Placenta previa poses significant risks to maternal and perinatal health, yet its management remains challenging. This comprehensive review synthesizes current evidence on maternal and perinatal outcomes in placenta previa, addressing its epidemiology, pathophysiology, diagnosis, and management strategies. Placenta previa complicates pregnancies, with increasing incidence linked to factors such as advanced maternal age and rising cesarean rates. Maternal complications, including hemorrhage and placenta accreta spectrum disorders, pose substantial risks. At the same time, perinatal outcomes are marked by increased rates of preterm birth, intrauterine growth restriction, and neonatal morbidity and mortality. Timely diagnosis and appropriate management, including antenatal corticosteroids and multidisciplinary care, are critical for optimizing outcomes. Future research should focus on improving diagnostic methods, evaluating novel interventions, and assessing long-term neurodevelopmental outcomes. This review underscores the importance of informed clinical practice and ongoing research efforts to enhance outcomes for women and infants affected by placenta previa.

BACKGROUND: Accurate discrimination between placenta accreta spectrum (PAS) and scar dehiscence with underlying non-adherent placenta is challenging both on prenatal ultrasound and intraoperatively. This can lead to overdiagnosis of PAS and unnecessarily aggressive management of scar dehiscence which increases the risk of morbidity. Several scoring systems have been published which combine clinical and ultrasound information to help diagnose PAS in women at high risk. This research aims to provide insights into the reliability and utility of existing accreta scoring systems in differentiating these two closely related but different conditions to contribute to improved clinical decision making and patient outcomes.
METHODS: A literature search was performed in four electronic databases. The references of relevant articles were also assessed. The articles were then evaluated according to the predefined inclusion criteria. Primary data for testing each scoring system were obtained retrospectively from two hospitals with specialized PAS services. Each scoring system was used to evaluate the predicted outcome of each case.
RESULTS: The literature review yielded 15 articles. Of these, eight did not have a clearly described diagnostic criteria for accreta, hence were excluded. Of the remaining seven studies, one was excluded due to unorthodox diagnostic criteria and two were excluded as they differed from the other systems hindering comparison. Four scoring systems were therefore tested with the primary data. All the scoring systems demonstrated higher scores for high-grade PAS compared to scar dehiscence (p < 0.001) with an excellent Area Under the receiver operator characteristic Curve ranging from 0.82 (95% CI 0.71-0.92) to 0.87 (95% CI 0.79-0.96) in differentiating between these two conditions. However, no statistically significant differences were noted between the low-grade PAS and scar dehiscence on all scoring systems.
CONCLUSIONS: Most published scoring systems have no clearly defined diagnostic criteria. Scoring systems can differentiate between scar dehiscence with underlying non-adherent placenta from high-grade PAS with excellent diagnostic accuracy, but not for low-grade PAS. Hence, relying solely on these scoring systems may lead to errors in estimating the risk or extent of the condition which hinders preoperative planning.

BACKGROUND: Cesarean hysterectomy is a dominant and effective approach during delivery in patients with placenta accreta spectrum (PAS). However, as hysterectomy results in a loss of fertility, conservative management is an alternative approach. However, management selection may be affected by a country\'s overall economic level. Thus the preferred treatment for PAS generates controversy in middle-income countries.
OBJECTIVE: We aimed to compare conservative management and cesarean hysterectomy for managing PAS in middle-income countries.
METHODS: China National Knowledge Infrastructure, Wanfang Med Online Databases, Cochrane Library, Ovid MEDLINE, PubMed, Web of Science, EMBASE, clinicaltrials.gov, and Scopus were searched from inception through to October 1, 2022.
METHODS: We included studies that evaluated at least one complication comparing conservative management and hysterectomy. All cases were diagnosed with PAS prenatally and intraoperatively.
METHODS: The primary outcomes were blood loss, adjacent organ damage, and the incidence of hysterectomy. Descriptive analyses were conducted for studies that did not meet the meta-analysis criteria. A fixed-effects model was used for studies without heterogeneity and a random-effects model was used for studies with statistical heterogeneity.
RESULTS: In all, 11 observational studies were included, with 975 and 625 patients who underwent conservative management and cesarean hysterectomy, respectively. Conservative management was significantly associated with decreased blood loss and lower risks of adjacent organ injury and hysterectomy. Conservative management significantly reduced blood transfusions, hospitalization duration, operative time, intensive care unit admission rates, and infections. There were no significant differences in the risks of coagulopathy, thromboembolism, or reoperation.
CONCLUSIONS: Given short-term complications and future fertility preferences for patients, conservative management appears to effectively manage PAS in middle-income countries. Owing to low levels of evidence, high heterogeneity and insufficient long-term follow-up data, further detailed studies are warranted.

OBJECTIVE: Clinical-sonographic scoring systems, combining clinical features and ultrasound imaging markers have been proposed for the screening of placenta accreta spectrum (PAS) but their usefulness in different set-ups remains limited. The aim of this study was to assess and compare different clinical-sonographic score systems performed from the midst of pregnancy for the prenatal evaluation of patients at risk of PAS at birth.
METHODS: PubMed/MEDLINE, Google Scholar, and Embase were searched between October 1982 and October 2022 to identify eligible studies.
METHODS: Observational studies providing data on the use of a combined clinical-ultrasound score systems performed from the midst of pregnancy for the prenatal evaluation of PAS.
METHODS: Study characteristics were evaluated by two independent reviewers using a predesigned protocol PROSPERO (CRD CRD42022332486). Heterogeneity between studies was analysed with Cochran\'s Q-test and the I2 statistics. Statistical heterogeneity was quantified by estimating the variance between the studies using I2 statistics. The area under the receiver operating characteristic curve AUC of ROC of each score and their summary (SROC) was calculated with sensitivity and specificity, and the integrated score of the SROC of all sonographic markers was calculated. Forest Plots were used to develop the meta-analysis of each sonographic marker and for the integrated sonographic score.
RESULTS: Of 1028 articles reviewed, 12 cohorts and two case-control studies including 1630 patients screening for PAS by clinical-ultrasound scores met the eligibility criteria. A diagnosis of PAS was reported in 602 (36.9%) cases for which 547 (90.9%) intraoperative findings and/or histopathologic data were described. A wide variation in reported sensitivities and specificities was observed between studies and in thresholds used for the identification of patients with a high probability of PAS at birth. The SAUCs of the individual sonographic scores ranged between 0.85 (the lowest) for sub-placental hypervascularity to 0.91 for placental location in the lower uterine segment (LUS), myometrial thinning, and placental lacunae and 0.95 for the loss of clear zone. Only four studies included placental bulging in their sonographic score system and therefore no meta-analysis for this score was performed. The integrated SAUC was 0.83 [95% Confidence Interval (95% CI) 79 to 0.86). Forest Plot analysis revealed an integrated sensitivities and specificities of 0.68 [95% CI 0.53-0.80], and 0.88 [95% CI 0.68 to 0.96]), respectively.
CONCLUSIONS: Clinical-sonographic score systems can contribute to the prenatal screening of patients at risk of PAS at birth. While we included multiple sonographic studies from the midst of pregnancy, standardized evaluation should be performed not only with strict ultrasound criteria for the placental position, mid third trimester gestational age at examination, and sonographic markers associated with PAS. Numeric sensitivities, specificities, NPVs, PPV, LR-, and LR+ should be recorded prospectively to assess their accuracy in different set-ups and PTP should be verified at delivery. The variables recommended for most predictive screening are: loss of clear zone underneath the placental bed, placentation in the LUS, and placenta lacunae.

BACKGROUND Placenta accreta syndrome (PAS) can lead to severe obstetric bleeding, and can be life-threatening. This study aimed to assess the precision of radiomics features derived from magnetic resonance imaging (MRI) for diagnosing PAS. MATERIAL AND METHODS A comprehensive search was conducted in the databases PubMed, Embase, Web of Science, and the Cochrane library from inception to October 2023. We included diagnostic accuracy studies utilizing radiomics-MRI in PAS patients, with histopathology serving as the reference standard. The overall diagnostic odds ratio (DOR), sensitivity, specificity, and area under the curve (AUC) were computed to gauge the diagnostic accuracy of MRI-based radiomic features in PAS patients. Quality assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies 2. Statistical analyses were carried out using Stata 14.2, MetaDiSc 1.4, and Review Manager 5.3 software. RESULTS Seven studies involving 672 patients were incorporated. The aggregated DOR, sensitivity, specificity, and AUC for radiomics in detecting PAS were 78% (confidence interval32, 191), 87% (76%, 93%), 92% (89%, 94%), and 0.93 (0.91-0.95), respectively. The meta-analysis revealed notable heterogeneity among the included studies, with no evidence of a threshold effect. Subgroup analysis demonstrated that, in comparison to manual segmentation and validation groups with ≤100 cases and internal validation datasets, automated segmentation, validation groups with >100 cases, and external validation datasets exhibited superior diagnostic performance . CONCLUSIONS Our findings indicate that MRI-based radiomic features perform well in assessing the diagnostic risk of PAS during prenatal diagnosis. This noninvasive and convenient tool may prove valuable in facilitating the identification of PAS.

OBJECTIVE: To assess the diagnostic accuracy of ultrasound for detecting placenta accreta spectrum (PAS) during the first trimester of pregnancy and compare it with the accuracy of second- and third-trimester ultrasound examination in pregnancies at risk for PAS.
METHODS: PubMed, EMBASE and Web of Science databases were searched to identify relevant studies published from inception until 10 March 2023. Inclusion criteria were cohort, case-control or cross-sectional studies that evaluated the accuracy of ultrasound examination performed at < 14 weeks of gestation (first trimester) or ≥ 14 weeks of gestation (second/third trimester) for the diagnosis of PAS in pregnancies with clinical risk factors. The primary outcome was the diagnostic accuracy of sonography in detecting PAS in the first trimester, compared with the accuracy of ultrasound examination in the second and third trimesters. The secondary outcome was the diagnostic accuracy of each sonographic marker individually across the trimesters of pregnancy. The reference standard was PAS confirmed at pathological or surgical examination. The potential of ultrasound and different ultrasound signs to detect PAS was assessed by computing summary estimates of sensitivity, specificity, diagnostic odds ratio and positive and negative likelihood ratios.
RESULTS: A total of 37 studies, including 5764 pregnancies at risk of PAS, with 1348 cases of confirmed PAS, were included in our analysis. The meta-analysis demonstrated that ultrasound had a sensitivity of 86% (95% CI, 78-92%) and specificity of 63% (95% CI, 55-70%) during the first trimester, and a sensitivity of 88% (95% CI, 84-91%) and specificity of 92% (95% CI, 85-96%) during the second/third trimester. Regarding sonographic markers examined in the first trimester, lower uterine hypervascularity exhibited the highest sensitivity (97% (95% CI, 19-100%)), and uterovesical interface irregularity demonstrated the highest specificity (99% (95% CI, 96-100%)). In the second/third trimester, loss of clear zone had the highest sensitivity (80% (95% CI, 72-86%)), and uterovesical interface irregularity exhibited the highest specificity (99% (95% CI, 97-100%)).
CONCLUSIONS: First-trimester ultrasound examination has similar accuracy to second- and third-trimester ultrasound examinations for the diagnosis of PAS. Routine first-trimester ultrasound screening for patients at high risk of PAS may improve detection rates and allow earlier referral to tertiary care centers for pregnancy management. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.