Society for Maternal-Fetal Medicine Special Statement: Emergency checklist, planning worksheet, and system preparedness bundle for placenta accreta spectrum.

Placenta accreta spectrum is a life-threatening complication of pregnancy that is underdiagnosed and can result in massive hemorrhage, disseminated intravascular coagulation, massive transfusion, surgical injury, multisystem organ failure, and even death. Given the rarity and complexity, most obstetrical hospitals and providers do not have comprehensive expertise in the diagnosis and management of placenta accreta spectrum. Emergency management, antenatal interdisciplinary planning, and system preparedness are key pillars of care for this life-threatening disorder. We present an updated sample checklist for emergent and unplanned cases, an antenatal planning worksheet for known or suspected cases, and a bundle of activities to improve system and team preparedness for placenta accreta spectrum.

A new step-wise surgical technique of knapsack-like uterine compression sutures for intractable postpartum hemorrhage in cesarean section.

BACKGROUND: Intractable postpartum hemorrhage (PPH) during cesarean section has been a significant concern for obstetricians. We aimed to explore the effectiveness and safety of a new type of uterine compression suture, the step-wise surgical technique of knapsack-like sutures for treating intractable PPH caused by uterine atony and placenta factors in cesarean section. METHODS: The step-wise surgical technique of knapsack-like sutures was established on the basis of the artful combination of vertical strap-like sutures and an annular suture-ligation technique. This novel surgical technique was applied to 34 patients diagnosed with PPH during cesarean section due to severe uterine atony and placental factors in our department. The hemostatic effects, clinical outcomes and follow-up visit results were all reviewed and analyzed. RESULTS: This new uterine compression suture successfully stopped bleeding in 33 patients, and the effective rate was 97.06%. Only 1 patient failed and was changed to use bilateral uterine arterial embolization and internal iliac artery embolization. The follow-up visits indicated that 33 patients restored menstruation except for 1 who was diagnosed with amenorrhea. The gynecological ultrasound tests of all the patients suggested good uterine involutions, and they had no obvious complaints such as hypogastralgia. CONCLUSIONS: This step-wise surgical technique of knapsack-like uterine compression sutures can compress the uterus completely. It is a technique that can conserve the uterus and fertility function without special equipment in caesarean section for PPH, with the characteristics of being safe, simple and stable (3 S) with rapid surgery, reliable hemostasis and resident doctor to operation (3R).

Effect of abnormal placentation on fetal heart function and neonatal outcomes.

OBJECTIVE: This study aimed to investigate the fetal modified (mod)-myocardial performance index (MPI) for fetal cardiac function in placenta percreta (PPC) pregnancies with placenta previa (PP) and assess neonatal outcomes. MATERIALS AND METHODS: This study included 104 pregnant women: 52 with PPC and 52 as the control group. Mod-MPI measurements and neonatal outcomes were evaluated in all cases. RESULTS: The PPC group had a significantly lower left ejection time (p = 0.044) and significantly higher mod-MPI (p = 0.001) than the control group. The optimal mod-MPI predictive cut-off value at the neonatal intensive care unit (NICU) admission in the PPC group was 0.53 with 53.8% specificity and 88.5% sensitivity (p = 0.019). The optimal mod-MPI predictive cut-off value at the 5th APGAR score below 7 in the PPC group was 0.55 with a specificity of 67.7% and a sensitivity of 76.2% (p = 0.016). CONCLUSION: Fetal MPI was higher in pregnant women with PPC compared to the control group. Among the PPC cases, those with MPI above a certain predictive level showed more frequent NICU admissions and lower APGAR scores.

The Underlying Molecular Mechanisms of the Placenta Accreta Spectrum: A Narrative Review.

Placenta accreta spectrum (PAS) disorders are characterized by abnormal trophoblastic invasion into the myometrium, leading to significant maternal health risks. PAS includes placenta accreta (invasion < 50% of the myometrium), increta (invasion > 50%), and percreta (invasion through the entire myometrium). The condition is most associated with previous cesarean deliveries and increases in chance with the number of prior cesarians. The increasing global cesarean rates heighten the importance of early PAS diagnosis and management. This review explores genetic expression and key regulatory processes, such as apoptosis, cell proliferation, invasion, and inflammation, focusing on signaling pathways, genetic expression, biomarkers, and non-coding RNAs involved in trophoblastic invasion. It compiles the recent scientific literature (2014-2024) from the Scopus, PubMed, Google Scholar, and Web of Science databases. Identifying new biomarkers like AFP, sFlt-1, ß-hCG, PlGF, and PAPP-A aids in early detection and management. Understanding genetic expression and non-coding RNAs is crucial for unraveling PAS complexities. In addition, aberrant signaling pathways like Notch, PI3K/Akt, STAT3, and TGF-ß offer potential therapeutic targets to modulate trophoblastic invasion. This review underscores the need for interdisciplinary care, early diagnosis, and ongoing research into PAS biomarkers and molecular mechanisms to improve prognosis and quality of life for affected women.

Diagnostic accuracy of ultrasound in the diagnosis of Placenta accreta spectrum: systematic review and meta-analysis.

OBJECTIVE: To evaluate the diagnostic accuracy of ultrasound and in the diagnosis of Placenta accreta spectrum (PAS). DATA SOURCES: Screening of MEDLINE, CENTRAL, other bases from inception to February 2022 using the keywords related to placenta accreta, increta, percreta, morbidly adherent placenta, and preoperative ultrasound diagnosis. STUDY ELIGIBILITY CRITERIA: All available studies- whether were prospective or retrospective- including cohort, case control and cross sectional that involved prenatal diagnosis of PAS using 2D or 3D ultrasound with subsequent pathological confirmation postnatal were included. Fifty-four studies included 5307 women fulfilled the inclusion criteria, PAS was confirmed in 2025 of them. STUDY APPRAISAL AND SYNTHESIS METHODS: Extracted data included settings of the study, study type, sample size, participants characteristics and their inclusion and exclusion criteria, Type and site of placenta previa, Type and timing of imaging technique (2D, and 3D), severity of PAS, sensitivity and specificity of individual ultrasound criteria and overall sensitivity and specificity. RESULTS: The overall sensitivity was 0.8703, specificity was 0.8634 with -0.2348 negative correlation between them. The estimate of Odd ratio, negative likelihood ratio and positive likelihood ratio were 34.225, 0.155 and 4.990 respectively. The overall estimates of loss of retroplacental clear zone sensitivity and specificity were 0.820 and 0.898 respectively with 0.129 negative correlation. The overall estimates of myometrial thinning, loss of retroplacental clear zone, the presence of bridging vessels, placental lacunae, bladder wall interruption, exophytic mass, and uterovesical hypervascularity sensitivities were 0.763, 0.780, 0.659, 0.785, 0.455, 0.218 and 0.513 while specificities were 0.890, 0.884, 0.928, 0.809, 0.975, 0.865 and 0.994 respectively. CONCLUSIONS: The accuracy of ultrasound in diagnosis of PAS among women with low lying or placenta previa with previous cesarean section scars is high and recommended in all suspected cases. TRIAL REGISTRATION: Number CRD42021267501.

Uterine artery embolization for postpartum hemorrhage with placenta accreta spectrum.

BACKGROUND: The reported success rate of uterine artery embolization (UAE) for postpartum hemorrhage (PPH) differs by the cause of bleeding; in some reports, UAE shows less successful results in patients with placenta accreta spectrum (PAS). PURPOSE: To evaluate the outcome of UAE for treating PPH associated with PAS. MATERIAL AND METHODS: From September 2011 to September 2021, 227 patients (mean age = 34.67±4.06 years; age range = 19-47 years) underwent UAE for managing intractable PPH. Patients were divided into two groups: those with PAS (n = 46) and those without PAS (n = 181). Delivery details, embolization details, and procedure-related outcomes were compared between the two groups. P values <0.05 were considered statistically significant. RESULTS: The technical success rate was 96.9% (n = 222) and the clinical success rate was 93.8% (n = 215). There were no significant differences in outcome of UAE between the two patient groups. The technical success rate was 95.7% (n = 44) in patients with PAS and 98.3% (n = 178) in patients without PAS (P = 0.267). The clinical success rate was 91.3% (n = 42) in patients with PAS and 95.6% (n = 173) in patients without PAS (P = 0.269). There were 24 cases of immediate complications, including pelvic pain (n = 20), urticaria (n = 3), and puncture site hematoma (n = 1). No major complication was reported. CONCLUSION: UAE is a safe and effective method to control intractable PPH for patients with or without PAS.

Placenta Accreta Spectrum Part I: anesthesia considerations based on an extended review of the literature.

"Placenta Accreta Spectrum" (PAS) describes abnormal placental adherence to the uterine wall without spontaneous separation at delivery. Though relatively rare, PAS presents a particular challenge to anesthesiologists, as it is associated with massive peripartum hemorrhage and high maternal morbidity and mortality. Standardized evidence-based PAS management strategies are currently evolving and emphasize: "PAS centers of excellence", multidisciplinary teams, novel diagnostics/pharmaceuticals (especially regarding hemostasis, hemostatic agents, point-of-care diagnostics), and novel operative/interventional approaches (expectant management, balloon occlusion, embolization). Though available data are heterogeneous, these developments affect anesthetic management and must be considered in planed anesthetic approaches. This two-part review provides a critical overview of the current evidence and offers structured evidence-based recommendations to help anesthesiologists improve outcomes for women with PAS. This first part discusses PAS management in centers of excellence, multidisciplinary care team, anesthetic approach and monitoring, surgical approaches, patient safety checklists, temperature management, interventional radiology, postoperative care and pain therapy. The diagnosis and treatment of hemostatic disturbances and preoperative prepartum anemia, blood loss, transfusion management and postpartum venous thromboembolism will be addressed in the second part of this series.

Placenta Accreta Spectrum Part II: hemostatic considerations based on an extended review of the literature.

"Placenta Accreta Spectrum" (PAS) is a rare but serious pregnancy condition where the placenta abnormally adheres to the uterine wall and fails to spontaneously release after delivery. When it occurs, PAS is associated with high maternal morbidity and mortality - as PAS management can be particularly challenging. This two-part review summarizes current evidence in PAS management, identifies its most challenging aspects, and offers evidence-based recommendations to improve management strategies and PAS outcomes. The first part of this two-part review highlighted the general anesthetic approach, surgical and interventional management strategies, specialized "centers of excellence," and multidisciplinary PAS treatment teams. The high rates of PAS morbidity and mortality are often provoked by PAS-associated coagulopathies and peripartal hemorrhage (PPH). Anesthesiologists need to be prepared for massive blood loss, transfusion, and to manage potential coagulopathies. In this second part of this two-part review, we specifically reviewed the current literature pertaining to hemostatic changes, blood loss, transfusion management, and postpartum venous thromboembolism prophylaxis in PAS patients. Taken together, the two parts of this review provide a comprehensive survey of challenging aspects in PAS management for anesthesiologists.

Can immunohistochemistry improve the pathological diagnosis of placenta accreta spectrum (PAS) disorders?

PURPOSE: The term of placenta accreta spectrum (PAS) disorder includes all grades of abnormal placentation. It is crucial for pathologist provide standardized diagnostic assessment to evaluate the outcome of management strategies. Moreover, a correct and safe diagnosis is useful in the medico-legal field when it becomes difficult for the gynecologist to demonstrate the suitability and legitimacy of demolitive treatment. The purposes of our study were: (1) to assess histopathologic features according to the recent guidelines; (2) to determine if immunohistochemistry can be useful to identify extravillous trophoblast (EVT) and to measure the depth of infiltration into the myometrium to improve the diagnosis of PAS. METHODS: The retrospective study was conducted on 30 cases of gravid hysterectomy with histopathologic diagnosis of PAS. To identify the depth of EVT, immunohistochemical stainings were performed using anti MNF116 (cytokeratins 5, 6, 8, 17, 19), actin-SM, HPL (Human Placental Lactogen), vimentin and GATA3 antibodies. RESULTS: Our cases were graded based on the degree of invasion of the myometrium. Ten were grade 1 (33.3%), 12 grade 2 (40%) and 8 grade 3A (26.7%). EVT invasion was best seen and evident by double immunostainings with actin-SM and cytokeratins, actin-SM and HPL, actin-SM and GATA3. CONCLUSION: The role of pathologist is decisive to determine the different grades of PAS. A better understanding of the depth of myometrial invasion can be achieved by the use of immunohistochemistry affording an important tool to obtain reproducible grading of PAS. This purpose is crucial in the setting of postoperative quality reviews and particularly in the forensic medicine field.

The effectiveness of single ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation in managing placenta accreta spectrum (PAS) disorder.

OBJECTIVE: To evaluate the feasibility and effectiveness of single ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation in managing placenta accreta spectrum (PAS) disorder. MATERIALS AND METHODS: We retrospectively analyzed 40 PAS patients between April 2017 and October 2021. All the patients received one session of HIFU treatment. Regular follow-up was done after HIFU treatment until normal menstruation returned and placental tissue disappeared. The patient's reproductive-related outcomes were obtained through telephone interviews. RESULTS: The median follow-up time for the 40 patients was 30.50 (15.75-44.00) months and the mean placental tissue elimination time was 45.29 ± 33.32 days. The mean duration of bloody lochia was 13.43 ± 10.01 days, with no incidences of severe bleeding. Notably, Linear regression analysis showed that the residual placenta volume before HIFU was a factor affecting the duration of bloody lochia after HIFU (R2 = 0.284, B = 0.062, P = 0.000). The normal menstrual return time was 58.71 ± 31.14 days. One (2.50%) patient developed an infection. Two (5.00%) patients were subjected to ultrasound-guided suction curettage for persistent vaginal discharge for more than one month without infection. Notably, 7 of the 18 patients who expressed reproductive plans became pregnant during the 4 to 53 months of follow-up without placental abnormalities. The remaining 11 patients were on contraceptives. CONCLUSIONS: Single HIFU is an effective treatment option for managing PAS. However, future studies on further treatment strategies to reduce complications and promote patient recovery after HIFU ablation are desirable.

Placenta percreta in primigravida with unscarred uterus complicated by uterine rupture and sudden maternal and fetal death: an autopsy case report.

Placenta percreta is a rare, aggressive, and severe form of the placenta accreta spectrum. One of its most devastating effects is the sudden rupture of uterus. Uterine scarring is the leading risk factor for uterine rupture, although it can also happen, but rarely, in an unscarred uterus showing more severe repercussions. The present study reported a case of an Egyptian primigravida female, aged 29 years old, at 32 weeks of gestation who died suddenly due to uterine rupture complicating placenta percreta, the diagnosis of which was first settled during autopsy. There was no history of abdominal trauma. No medical history of significance was present. Autopsy denoted an intrauterine fetal death of 32 weeks gestational age. The fundus of the uterus had a laceration (rupture) of the uterine wall including the serosa and myometrium. The placenta has extensively infiltrated the fundus uterine wall and penetrated the myometrium and serosa. Histopathological examination of the ruptured site on the uterus confirms total invasion of the uterine wall by chorionic villi with the presence of hemorrhage and fibrin indicating placenta percreta. Uterine rupture due to placenta percreta may go unnoticed, especially when no associated high-risk factors exist. The current case depicts that placenta percreta is a rare but critical complication of pregnancy that may exist at any stage of pregnancy without any associated high-risk factors with unusual symptoms and leads to uterine rupture and sudden death.

Antepartum unscarred uterine rupture caused by placenta percreta: a case report and literature review.

The main risk for uterine rupture is the presence of a uterine scar due to prior cesarean delivery or other uterine surgery. However, rupture in an unscarred uterus is extremely rare, and risk factors include multiple gestations, trauma, congenital anomalies, use of uterotonics and placenta accreta spectrum.Placenta accreta spectrum, also known as morbidly adherent placenta, is becoming increasingly common and is associated with significant maternal and neonatal morbidity and mortality.We report a case of unscarred uterine rupture due to placenta percreta in a multiparous woman that required emergency peripartum hysterectomy.

[Establishment of Decision Tree Prediction Model for Risk Factors of Placenta Accreta Spectrum Disorders].

Objective: To analyze the risk factors for placenta accreta spectrum (PAS) disorders and to construct preliminarily a decision tree prediction model for PAS, to help identify high-risk populations, and to provide reference for clinical prevention and treatment. Methods: By accessing the electronic medical record system, we retrospectively analyzed the relevant data of 2022 women who gave birth between January 2020 and September 2020 in a hospital in Chengdu. Univariate logistic regression and multivariate logistic regression were conducted to analyze the risk factors of PAS. SPSS Clementine12.0 was used to make preliminary exploration for the decision tree prediction model of PAS risk factors. Results: Results of logistic regression suggested that the top three risk factors for PAS included the following, the risk of PAS in pregnant women with placenta previa was 8.00 times that in pregnant women without placenta previa (95% CI: 5.24-12.22), the risk of PAS in multiple pregnancies was 2.52 times that in singleton pregnancies (95% CI: 1.72-3.69), and the risk of PAS in pregnant women who have had three or more abortions was 1.89 times that in those who have not had abortion (95% CI: 1.11-3.20). Results of the decision tree prediction model based on C5.0 algorithm were as follows, placenta previa was the most important risk factor, with as high as 93.33% (140/150) patients developed PAS when they had placenta previa; when in vitro fertilization-embryo transfer (IVF-ET) was the only factor the subjects had, the incidence of PAS was 59.91% (133/222); the incidence of PAS was as high as 75.96% (79/104) when the subjects had both IVF-ET and a history of uterine surgery; the probability of PAS in women who had induced abortion in the past was 48.46% (205/423); the probability of PAS in women who had undergone uterine surgery previously was 10.54% (37/351); the incidence of PAS was as high as 100.00% (163/163) when the subjects had induced abortion previously and uterine surgery history. The model showed a prediction accuracy of 85.41% for the training set and a prediction accuracy of 83.36% for the testing set, both being high rates of accuracy. Conclusion: The decision tree prediction model can be used for rapid and easy screening of patients at high risk for PAS, so that the likelihood of PAS can be actively and dynamically assessed and individualized preventive measures can be taken to avoid adverse outcomes.

Searching for placenta percreta: a prospective cohort and systematic review of case reports.

BACKGROUND: Placenta percreta is described as the most severe grade of placenta accreta spectrum and accounts for a quarter of all cases of placenta accreta spectrum reported in the literature. OBJECTIVE: We investigated the hypothesis that placenta percreta, which has been described clinically as placental tissue invading through the full thickness of the uterus, is a heterogeneous category with most cases owing to primary or secondary uterine abnormality rather than an abnormally invasive form of placentation. STUDY DESIGN: We have evaluated the agreement between the intraoperative findings using the International Federation of Gynecology and Obstetrics classification with the postoperative histopathology diagnosis in a prospective cohort of 101 consecutive singleton pregnancies presenting with a low-lying placenta or placenta previa, a history of at least 1 prior cesarean delivery and ultrasound signs suggestive of placenta accreta spectrum. Furthermore, a systematic literature review of case reports of placenta percreta, which included histopathologic findings and gross images, was performed. RESULTS: Samples for histologic examination were available in 80 of 101 cases of the cohort, which were managed by hysterectomy or partial myometrial resection. Microscopic examination showed evidence of placenta accreta spectrum in 65 cases (creta, 9; increta, 56). Of 101 cases included in the cohort, 44 (43.5%) and 54 (53.5%) were graded as percreta by observer A and observer B, respectively. There was a moderate agreement between observers. Of note, 11 of 36 cases that showed no evidence of abnormal placental attachment at delivery and/or microscopic examination were classified as percreta by both observers. The systematic literature review identified 41 case reports of placenta percreta with microscopic images and presenting symptomatology, suggesting that most cases were the consequence of a uterine rupture. The microscopic descriptions were heterogeneous, and all descriptions demonstrated histology of placenta creta rather than percreta. CONCLUSION: Our study supported the concept that placenta accreta is not an invasive disorder of placentation but the consequence of postoperative surgical remodeling or a preexisting uterine pathology and found no histologic evidence supporting the existence of a condition where the villous tissue penetrates the entire uterine wall, including the serosa and beyond.

Prospective evaluation of impact of post-Cesarean section uterine scarring in perinatal diagnosis of placenta accreta spectrum disorder.

OBJECTIVE: Standardized ultrasound imaging and pathology protocols have recently been developed for the perinatal diagnosis of placenta accreta spectrum (PAS) disorders. The aim of this study was to evaluate prospectively the effectiveness of these standardized protocols in the prenatal diagnosis and postnatal examination of women presenting with a low-lying placenta or placenta previa and a history of multiple Cesarean deliveries (CDs). METHODS: This was a prospective cohort study of 84 consecutive women with a history of two or more prior CDs presenting with a singleton pregnancy and low-lying placenta/placenta previa at 32-37 weeks' gestation, who were referred for perinatal care and management between 15 January 2019 and 15 December 2020. All women were investigated using the standardized description of ultrasound signs of PAS proposed by the European Working Group on abnormally invasive placenta. In all cases, the ultrasound features were compared with intraoperative and histopathological findings. Areas of abnormal placental attachment were identified during the immediate postoperative gross examination and sampled for histological examination. The data of a subgroup of 32 women diagnosed antenatally as non-PAS who had complete placental separation at birth were compared with those of 39 cases diagnosed antenatally as having PAS disorder that was confirmed by histopathology at delivery. RESULTS: Of the 84 women included in the study, 42 (50.0%) were diagnosed prenatally as PAS and the remaining 42 (50.0%) as non-PAS on ultrasound examination. Intraoperatively, 66 (78.6%) women presented with a large or extended area of dehiscence and 52 (61.9%) with a dense tangled bed of vessels or multiple vessels running laterally and craniocaudally in the uterine serosa. A loss of clear zone was recorded on grayscale ultrasound imaging in all 84 cases, while there was no case with bladder-wall interruption or with a focal exophytic mass. Myometrial thinning (< 1 mm) in at least one area of the anterior uterine wall was found in 41 (97.6%) of the 42 cases diagnosed as non-PAS on ultrasound and 37 (88.1%) of the 42 diagnosed antenatally as PAS. Histological samples were available for all 48 hysterectomy specimens with abnormal placental attachment and for the three cases managed conservatively with focal myometrial resection and uterine reconstruction. Villous tissue was found directly attached to the superficial myometrium (placenta creta) in six of these cases and both creta villous tissue and deeply implanted villous tissue within the uterine wall (placenta increta) were found in the remaining 45 cases. There was no evidence of percreta placentation on histology in any of the PAS cases. Comparison of the main antenatal ultrasound signs and perioperative macroscopic findings between the two subgroups correctly diagnosed antenatally (32 non-PAS and 39 PAS) showed no significant difference with respect to the distribution of myometrial thinning and the presence of a placental bulge on ultrasound and of anterior uterine wall dehiscence intraoperatively. Compared with the non-PAS subgroup, the PAS subgroup showed significantly higher placental lacunae grade (P < 0.001) and more often hypervascularity of the uterovesical/subplacental area (P < 0.001), presence of bridging vessels (P = 0.027) and presence of lacunae feeder vessels (P < 0.001) on ultrasound examination, and increased vascularization of the anterior uterine wall intraoperatively (P < 0.001). CONCLUSIONS: Remodeling of the lower uterine segment following CD scarring leads to structural abnormalities of the uterine contour on both ultrasound examination and intraoperatively, independently of the presence of accreta villous tissue on microscopic examination. These anatomical changes are often reported as diagnostic of placenta percreta, including cases with no histological evidence of PAS. Guided histological examination could improve the overall diagnosis of PAS and is essential to obtain evidence-based epidemiologic data. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Evaluation of classic and novel ultrasound signs of placenta accreta spectrum.

OBJECTIVES: Improvement in the antenatal diagnosis of placenta accreta spectrum (PAS) would allow preparation for delivery in a referral center, leading to decreased maternal morbidity and mortality. Our objectives were to assess the performance of classic ultrasound signs and to determine the value of novel ultrasound signs in the detection of PAS. METHODS: This was a retrospective cohort study of women with second-trimester placenta previa who underwent third-trimester transvaginal ultrasound and all women with PAS in seven medical centers. A retrospective image review for signs of PAS was conducted by three maternal-fetal medicine physicians. Classic signs of PAS were defined as placental lacunae, bladder-wall interruption, myometrial thinning and subplacental hypervascularity. Novel signs were defined as small placental lacunae, irregular placenta-myometrium interface (PMI), vascular PMI, non-tapered placental edge and placental bulge towards the bladder. PAS was diagnosed based on difficulty in removing the placenta or pathological examination of the placenta. Multivariate regression analysis was performed and receiver-operating-characteristics (ROC) curves were generated to assess the performance of combined novel signs, combined classic signs and a model combining classic and novel signs. RESULTS: A total of 385 cases with placenta previa were included, of which 55 had PAS (28 had placenta accreta, 11 had placenta increta and 16 had placenta percreta). The areas under the ROC curves for classic markers, novel markers and a model combining classic and novel markers for the detection of PAS were 0.81 (95% CI, 0.75-0.88), 0.84 (95% CI, 0.77-0.90) and 0.88 (95% CI, 0.82-0.94), respectively. A model combining classic and novel signs performed better than did the classic or novel markers individually (P = 0.03). An increasing number of signs was associated with a greater likelihood of PAS. With the presence of 0, 1, 2 and ≥ 3 classic ultrasound signs, PAS was present in 5%, 24%, 57% and 94% of cases, respectively. CONCLUSIONS: We have confirmed the value of classic ultrasound signs of PAS. The use of novel ultrasound signs in combination with classic signs improved the detection of PAS. These findings have clinical implications for the detection of PAS and may help guide the obstetric management of patients diagnosed with these placental disorders. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Percreta score to differentiate between placenta accreta and placenta percreta with ultrasound and MR imaging.

INTRODUCTION: The objective of this study was to assess the performance of ultrasound and magnetic resonance imaging (MRI) features in helping to classify the type of placenta accreta spectrum (PAS; accreta/increta vs percreta), alone or combined in a predictive score. MATERIAL AND METHODS: We conducted a retrospective study in 82 pregnant women with PAS who underwent ultrasound and MRI examination of the pelvis before delivery (from an initial cohort of 185 women with PAS). We estimated the sensitivity, specificity and accuracy of MRI and ultrasound in the diagnosis of the type of PAS. We analyzed cesarean and imaging features using univariable logistic regression analysis. We constructed a nomogram to predict the risk of placenta percreta and validated it with bootstrap resampling, then used receiver operating characteristic curves to assess the performance of the model in distinguishing between placenta percreta and placenta accreta/increta. RESULTS: Among the 82 patients, 29 (35%) had placenta accreta/increta and 53 (65%) had placenta percreta. The best features to discriminate between placenta accreta/increta and placenta percreta with ultrasound were increased vascularization at the uterine serosa-bladder wall interface (odds ratio [OR] 7.93; 95% confidence interval [CI] 2.78-24.99; p < 0.01) and the number of lacunae without a hyperechogenic halo (OR 1.36; 95% CI 1.14-1.67; p = 0.012). Concerning MRI markers, heterogeneous placenta (OR 12.89; 95% CI 3.05-89.16; p = 0.002), dark intraplacental bands (OR 12.89; 95% CI 3.05-89.16; p = 0.002) and bladder wall interruption (OR 15.89; 95% CI 4.78-73.33; p < 0.001) had a higher OR in discriminating placenta accreta/increta from placenta percreta. The nomogram yielded areas under the curve of 0.841 (95% CI 0.754-0.927) and 0.856 (95% CI 0.767-0.945), after bootstrap resampling, for the accurate prediction of placenta percreta. CONCLUSIONS: The nomogram we developed to predict the risk of placenta percreta among patients with PAS had good discriminative capabilities. This performance and its impact on maternal morbidity should be confirmed by future prospective studies.

Shear-wave elastography for detection of placenta percreta: a case-controlled study.

BACKGROUND: Prenatal diagnosis of placenta percreta (PP) is important to be able to provide effective management and a multidisciplinary approach to minimize the complications. PURPOSE: To evaluate the role of shear-wave elastography (SWE) in the prenatal diagnosis of PP. MATERIAL AND METHODS: A total of 18 women with PP and 20 pregnant women with normal placenta in the second or third trimesters were included in this prospective study. SWE was used to determine the elasticities of the placenta (in the maternal edge of the placenta) and myometrium. The obstetric data regarding grayscale and Doppler ultrasonography, and perinatal outcomes were reviewed. A mean placental SW velocity (SWV) cut-off value was determined to predict the presence of placental adherence. RESULTS: The SWV values of the PP group in the maternal edge of the placenta were significantly higher than those of the control group (1.95 ± 0.19 m/s and 1.69 ± 0.23 m/s; P = 0.001). Myometrial SWV was also higher in the PP group compared to the control group (2.25 ± 0.39 m/s and 1.90 ± 0.71 m/s; P = 0.002). A receiver operating characteristic (ROC) curve analysis was performed and the best cut-off value of placental SWV was determined as 1.92 m/s with sensitivity of 58% and specificity of 80%, to predict the placental adherence in patients with PP. CONCLUSION: Placental stiffness was significantly higher in patients with PP than in pregnant women with normally localized placenta. Thus, we thought that SWE of the placenta might be used as an alternative method in the diagnosis of PP.

Outcomes of pregnancies at high-risk for placenta accreta spectrum following negative diagnostic imaging.

OBJECTIVES: To assess the pretest and negative post-test probability for placenta accreta spectrum (PAS) in a group of patients with high-risk clinical factors. METHODS: We included patients with suspected and/or confirmed PAS at our institution over 8 years. Sonography performed by maternal-fetal medicine specialists, and selected patients underwent MRI. Imaging was considered positive if either sonography or MRI suggested PAS. Histopathology was the gold standard for diagnosis of PAS. We assessed the pretest and negative imaging-test probability, and resources required. RESULTS: We identified 82 high-risk patients with the following: (1) a history of ≥1 cesarean section and/or intrauterine gynecologic procedure and placenta previa in the index pregnancy; (2) a history of >3 cesarean deliveries and/or gynecologic procedures regardless of placental location; (3) prior PAS disorder, or retained placenta requiring manual extraction and/or curettage, complicated by postpartum hemorrhage; and (4) suspected cesarean section scar pregnancy. Histopathology confirmed PAS in 52 patients, with pretest probability of 63%. Imaging correctly identified 44/50 cases with PAS, and excluded this condition in 24/30 cases. Thus, the positive and negative post-test probability for PAS following negative imaging was 88 and 20%, respectively. Of the six patients with false-negative imaging, all had either surgical complications or required care beyond that for routine cesarean section. CONCLUSIONS: Although diagnostic imaging is sensitive, the negative posttest probability remains high in women with high pretest probability for PAS. Therefore, women at high risk for PAS should be managed in experienced centers by a multidisciplinary team even if imaging is negative.

Pulsatile vessel at the posterior bladder wall: A new sonographic marker for placenta percreta.

OBJECTIVE: We investigated using "pulsatile vessels at the posterior bladder wall" as a novel sonographic marker to demonstrate the severity of placenta accreta spectrum (PAS). METHODS: This observational case-control study of 30 pregnant women was performed at Hackensack Meridian Health's Center for Abnormal Placentation in 2020. The case group was made up of women with historically described sonographic signs of PAS and was compared against two control groups: (1) women with uncomplicated placenta previa and (2) women with no evidence of placenta previa sonographically. All patients were evaluated with Color Flow Doppler ultrasound to assess the presence of arterial vessels at the posterior bladder wall. The flow characteristics and resistance indices (RI) were noted in the presence of pulsatile vessels. All patients' placentation was clinically confirmed at delivery. Patients with clinical invasive placentation underwent histopathological diagnosis to confirm disease presence. RESULTS: Hundred percent of subjects in our series with suspected PAS exhibited pulsatile arterial vessels at the posterior bladder wall sonographically with a low RI of 0.38 ± 0.1 at an average of 24.6 ± 5.2 gestational weeks. Cases were histopathologically confirmed to have placenta percreta after delivery. Patients in either of the control groups did not display pulsatile vessels at the posterior bladder wall during antenatal sonographic evaluations and had no clinical evidence of PAS. CONCLUSION: The presence of posterior urinary bladder wall pulsatile arterial vessels with low RI, in addition to traditional sonographic markers increases the suspicion of severe PAS. Thus, these findings allow for the greater opportunity for coordination of patient care prior to delivery.