Non-Previa Placenta Accreta Spectrum in a Woman with Previous Cesarean Section: A Case Report and Review of Pathogenesis, Etiology, and Management Perspectives

Early first-trimester transvaginal ultrasound is indicated in pregnancy after previous Cesarean delivery: should it be mandatory?

Assessment of placenta accreta spectrum at vaginal birth after cesarean delivery

In vitro fertilization as an independent risk factor for placenta accreta spectrum

Association between short interpregnancy interval and placenta accreta spectrum

ABSTRACTObjectiveAccurate differentiation between placenta accreta spectrum (PAS) and uterine‐scar dehiscence with underlying non‐adherent placenta is often challenging, even for PAS experts, both prenatally and intraoperatively. We investigated the use of standardized two‐dimensional grayscale ultrasound and Doppler imaging markers in differentiating between these closely related, yet distinct, conditions.MethodsThis was a retrospective cohort study conducted in two centers with specialized PAS services. All consecutive women with at least one previous Cesarean delivery and a current pregnancy with a low‐lying placenta or placenta previa, for whom detailed prenatal ultrasound, management and outcome information was available for review by the research team, were included. PAS was diagnosed clinically by the abnormal adherence of the placenta to the uterus. The PAS cases were classified using the International Federation of Gynecology and Obstetrics clinical classification. Grade 1 was considered low‐grade PAS while Grades 2 and 3 were classified as high‐grade PAS. The ultrasound markers were categorized according to their underlying pathophysiology, including lower uterine segment (LUS) remodeling, uteroplacental vascular remodeling and serosal hypervascularity. The combined ultrasound features were analyzed among the PAS and non‐PAS subgroups using the chi‐square test or Fisher's exact test, and univariable and multivariable logistic regression analysis. Additionally, receiver‐operating‐characteristics (ROC) curves were used to evaluate the diagnostic accuracy of the combined ultrasound features in differentiating between high‐grade PAS and uterine‐scar dehiscence.ResultsOut of the 150 cases retrieved, six cases were excluded for not meeting the eligibility criteria. The included 144 cases comprised 89 cases of PAS, 23 cases of uterine‐scar dehiscence and 32 cases of uncomplicated low‐lying placenta or placenta previa. Among the PAS cases, there were 16 cases of low‐grade PAS and 73 of high‐grade PAS. Combined signs of LUS remodeling were present in most cases of uterine‐scar dehiscence (20/23 (87.0%)) and high‐grade PAS (67/73 (91.8%)) (P = 0.444), while these signs were absent in cases of low‐grade PAS (0/16) and uncomplicated low‐lying placenta or placenta previa (0/32). A subgroup analysis of cases with all LUS remodeling features present revealed that the combined signs of serosal hypervascularity (adjusted odds ratio (aOR), 41.2 (95% CI, 7.5–225.3)) and uteroplacental vascular remodeling (aOR, 116.0 (95% CI, 15.3–878.3)) were significantly associated with high‐grade PAS. Diagnostic accuracy testing within this subgroup revealed an area under the ROC curve (AUC) of 0.90 (95% CI, 0.81–0.99), sensitivity of 89.6% (95% CI, 79.7–95.7%) and specificity of 90.0% (95% CI, 68.3–98.8%) for the diagnosis of high‐grade PAS when all signs of uteroplacental vascular remodeling were present. If both signs of serosal hypervascularity were present, the AUC was 0.84 (95% CI, 0.74–0.95) with a sensitivity of 83.6% (95% CI, 72.5–91.5%) and specificity of 85.0% (95% CI, 62.1–96.8%) for the diagnosis of high‐grade PAS.ConclusionsThe combined ultrasound markers of LUS remodeling are common in both high‐grade PAS and uterine‐scar dehiscence, while the combined features of abnormal vascularity (uteroplacental vascular remodeling and serosal hypervascularity) are specific to high‐grade PAS. Understanding these pathophysiological differences would enhance the diagnostic accuracy of ultrasound in distinguishing between these two conditions. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Previous preterm cesarean delivery and risk of uterine rupture in subsequent trial of labor—a national cohort study

Maternal circulating biomarkers associated with placenta accreta spectrum disorders.

Placenta accreta spectrum (PAS) refers to excessive placental invasion into the maternal uterus and it is associated with high risk of obstetric haemorrhage and adverse maternal-neonatal outcomes. Currently, no specific circulating biomarkers of PAS have been identified. Given that in PAS disorders, the depth and the extension of placental invasion into the uterus are expected to be increased, in this study, we analysed plasma levels of syncytiotrophoblast-derived extracellular vesicles (STBEVs) in women with placenta previa (PP), at a high risk of PAS disorders, and pregnant women with normal placentation. Venous blood samples were collected from 35 women with ultrasonographic diagnosis of PP and 35 women with normal placentation, matched for gestational age. Plasma samples were ultracentrifuged at 120.000 g to collect extracellular vesicles (EVs). To identify and quantify plasma placenta–derived EVs (or STBEVs), EVs were analysed by flow cytometry using a monoclonal antibody against placental alkaline phosphatase (PLAP). Plasma levels of STBEVs were significantly higher in PP patients compared to controls. Plasma levels of STBEVs in women with PP and PAS showed a trend to a higher concentration compared to women with PP without PAS, although not reaching a statistical significance. Circulating STBEVs are potential candidates as biological markers to be integrated to ultrasonography in the antenatal screening programme for PAS. More studies are needed to confirm our observation in a larger cohort of patients and to analyse a possible association between high circulating levels of STBEVs and PAS.

Background & Objective: Placenta Accreta Spectrum (PAS) is a condition in pregnant women where trophoblastic tissue attaches abnormally to the uterus myometrium, causing maternal deaths. Major risk factors include placenta previa and cesarean delivery, which is increasing without medical indication. This study was conducted with aim to explore the risk factors of PAS, clinical outcomes of affected patients, and strategies to minimize maternal morbidity and mortality.Materials and Methods: A total of 142 women who had undergone at least one cesarean delivery in the past were included. Among them, 85 women had placenta accreta spectrum (PAS) in their current pregnancy (group 1), while 57 did not have PAS (group 2). The information regarding their demographics and previous gynecological history, including placenta previa were collected. P<0.05 was considered statistically significant.Results: The risk of placenta accreta spectrum (PAS) is significantly higher in cases where there has been a previous cesarean delivery and placenta previa (p<0.05). There were no significant differences between past elective or emergent cesarean delivery (p>0.05). PAS was associated with more emergent cesarean deliveries (p<0.001) and hysterectomies (p<0.001). Moreover, 97% of patients with history of placenta previa developed PAS (p<0.001). Most of the patients who underwent hysterectomy had PAS and placenta previa (p<0.001). There was no significant correlation between previous hysteroscopies and curettages and a higher risk of PAS (p>0.05).Conclusion: Women with previous cesarean delivery are significantly at risk of placenta accreta in their future pregnancies. Pregnant women should avoid insisting on elective cesarean delivery without medical indication. Planned cesarean delivery could reduce the maternal complications.

Trends, characteristics, and outcomes of placenta accreta spectrum: a national study in the United States

Diagnosis of placenta accreta spectrum (PAS) Before 2018, there were various terms used to describe PAS disorders, such as morbidly adherent placenta (US/Egypt/Israel), adhesive placenta (Italy/Argentina), and pernicious placenta (Chinese mainland). An inclusive standardized terminology PAS was proposed by the International Federation of Gynecology and Obstetrics (FIGO) in March 2018 and endorsed by the Society for Maternal-Fetal Medicine and American College of Obstetricians and Gynecologists, Royal College of Obstetricians and Gynecologists, and the Society of Obstetricians and Gynecologists of Canada.1 It describes the grade of PAS which are separated into three categories: placenta adherenta or creta (PC) when the villi adhere directly to the myometrium without a decidual interface, placenta increta (PI) when the villi invade the myometrium and placenta percreta (PP) when the villi invade the full thickness of the uterine wall including the serosa.2 If the terminology is now agreed on, there are still some issues with the diagnosis of PAS. The prenatal diagnosis of PAS and in particular the differential diagnosis between abnormally adherent placenta (creta/sticky placenta/placenta retention) and abnormally invasive placenta (increta/percreta) is essential for the development of adequate management protocols and accurate epidemiology data. In many cases of abnormally adherent placenta, the obstetricians can often manage to remove the placenta and stop the bleeding with balloon or compressive suture. However, in cases of abnormally invasive placenta, the surgeons will not be able to detach the placenta from the uterine wall and partial myometrial resection with uterine reconstruction or hysterectomy will be needed.3 A systematic review and meta-analysis including 29 studies and 7001 cases of PAS found that the prevalence of PAS was highly variable, ranging between 0.01% and 1.1% with an overall pooled prevalence of 0.17% (95% confidence interval, 0.14–0.19).4 Similarly, variability in incidence were found more specifically for placenta previa accreta data.5 This considerable heterogeneity in prevalence and incidence of PAS highlights methodologic inconsistencies between studies with regards to clinical criteria that were used for the diagnosis of both placenta previa and PAS and the histopathologic confirmation of the diagnosis and differential diagnosis between adherent and invasive accreta placentation. The clinical and histologic criteria for the diagnosis of accreta placentation were first reported by Irving and Hertig in 19376 and included the absence of decidual layer between the placenta and myometrium with direct attachment of the villi to the myometrium resulting in the abnormal attachment of the placenta at delivery. All the cases described in this first series were cases of PC or placenta adherenta (none were invasive). Histopathologic examination is the confirmatory gold standard,7 but most current authors of PAS cohort series do not provide complete and transparent information on both clinical and histopathological findings. The clinical and pathologic diagnostic standards have stagnated, with little change over the last 80 years.3 The lack of standardized protocols for the confirmation diagnosis at birth has led to the overdiagnosis of both PC and PP. Cases diagnosed as PC but using criteria that are similar to complete or partial placenta retention and often include: (1) difficult manual and/or piecemeal removal of the placenta; (2) and/or evidence of placental separation after 20 minutes despite active management (uterotonics/cord traction); (3) and/or bleeding (massive) from the placental site after delivery of the placenta in "well contracted" uterus (at both vaginal birth and C-section). Similarly, at least 50% of PP are not PAS. Many authors refer to PP when they observe a uterine "window" (dehiscence with the placental visible through it). These can be small or large, sometime involving >50% of the lower segment and are common in women with multiple cesarean deliveries.3 The area can be covered by adhesions and dilated vessels but in most cases, the placenta is just simply lying under the dehiscence (very thin or no myometrium left) and has not perforates the serosa8 and thus should not be reported as PP. Cases of pseudo-percreta placenta previa in women are commonly reported as PP but those are not actual PAS, unless there is an area of PC or PI around the dehiscence area.9 A consensus panel of experts in perinatal pathology was recently convened to recommend terminology and reporting elements unified across the spectrum of PAS specimens (ie, delivered placenta, total or partial hysterectomy with or without extrauterine tissues, curetting for retained products of conception).10 The proposed nomenclature under the umbrella diagnosis of PAS replaces the traditional categorical terminology (placenta accreta, increta, percreta) with a descriptive grading system that parallels the guidelines endorsed by the FIGO. Valuable clinical information on the serosal vascularity, uterine dehiscence, and extension of the accreta area is added with the description of the macroscopic examination during the surgical procedure and immediate dissection of the specimen.11 Hysterectomy specimens are better examined fresh to allow more detailed macroscopic description and to obtain guided biopsies from the area of the placenta that is abnormally attached to the uterine wall (or partial myometrial reresection).11 For hysterectomy specimens with the placenta in situ, the specimen should be examined carefully to find out the invasive area using gently separating by fingers, avoiding damaging the placental-uterine interface. This methodological approach is cost-effective and increases the quality of the histologic sampling. It facilitates immediate correlation with imaging and intraoperative findings, as well as standardized tissue sampling for accurate differential diagnosis among the different grades of villous invasiveness. All specimens should be examined by a senior pathologist with expertise in PAS histopathology and perinatal pathologists should be part of multidisciplinary teams involved the management PAS disorders. FIGO classification for PAS PAS includes all grades of abnormal placentation and is used as the basis for the development of a new clinical classification proposed by the FIGO12: (1) Grade 1 – Abnormally adherent placenta (PC) when the villi adhere directly to the myometrium without a decidual interface. (2) Grade 2 – Abnormally invasive placentation (PI) when the villi invade into the myometrium. (3) Grade 3 – Abnormally invasive placentation (PP) when the villi invade the full thickness of the uterine wall either to the serosa or beyond. They are subdivided into: Grade 3a, limited to and including the uterine serosa; Grade 3b, when there is urinary bladder invasion; Grade 3c, when there is invasion of other pelvic tissue/organs. Many clinicians and the World Health Organization international classification of diseases (www.who.int/classifications/icd) continue to use the 1937 Irving and Hertig definition for placenta accreta and therefore make no distinction between different grades of PAS.1 Only 10% of studies on the prenatal diagnosis of PAS and placenta previa accreta provide detailed histopathology data on the different grades of PAS, and the corresponding distribution varies widely.4,5 The use of the FIGO classification and perinatal pathology classification together with guided sampling will increase the quality of histologic sampling and provide more accurate clinic-pathologic correlations with ultrasound images obtained before surgery. Images of the operating field should be taken in each case. In conclusion, improving the quality of prenatal diagnosis, especially differentiation between abnormally invasive placenta and abnormally adherent placenta is very important for management. Histopathologic confirmation of diagnosis is the golden standard for PAS and perinatal pathologists should be part of multidisciplinary team involved in the management of PAS. This new FIGO classification, together with the standardized prenatal imaging descriptions and proforma reporting for suspected antenatally with placenta accreta,13 have been established with the intent of improving the overall quality of epidemiologic data on PAS incidence. This system may also improve management outcome data, by allowing stratification using the standardized different grades of PAS and the development of targeted screening protocols for women at high risk of PAS.14 Funding None. Conflicts of Interest None.

Background: Placenta accreta spectrum (PAS) refers to abnormal placental attachment, categorized into placenta accreta, increta, and percreta, with varying severity. The incidence of PAS has risen alongside the increasing rate of caesarean sections. PAS is a significant cause of maternal complications, including bleeding, hysterectomies of necessity and intestinal or urinary surgical complications, and of foetal complications, preterm birth or foetal anaemia. Early diagnosis is crucial for its management and for improving its outcomes. Materials and Methods: This retrospective study, conducted at the County Emergency Clinical Hospital "Saint Andrew the Apostle", Constanța, analysed cases of placenta praevia and PAS from 2018 to 2022. Data were collected from observation sheets and operative protocols, involving 13,841 patients. Placenta praevia and PAS were diagnosed using ultrasound and MRI and confirmed by histopathology. Results: Among the 13,841 deliveries, 25 cases of placenta praevia (0.82% incidence) and 17 cases of PAS (0.57% incidence) were identified. Ultrasound demonstrated 88% sensitivity, and MRI 94% sensitivity for PAS detection. Of the 17 PAS cases, 11 were diagnosed as placenta accreta, 3 were diagnosed as placenta increta, and 3 as placenta percreta, with all percreta cases involving bladder invasion. Hysterectomy was the standard surgical treatment. Discussion: The risk factors for PAS included previous caesarean sections (94.1% of PAS cases), smoking, and uterine fibroids. The study confirmed the importance of early imaging and the involvement of a multidisciplinary team in managing PAS, particularly in complex cases with bladder involvement. Caesarean section followed by hysterectomy was the preferred surgical approach. Conclusions: Smoking, uterine scars, and uterine fibroids are significant risk factors for placenta praevia with pathological adhesion. Ultrasound and MRI are highly accurate in diagnosing PAS, with histopathology providing definitive confirmation. Multidisciplinary care is essential in managing complex cases, ensuring optimal maternal and foetal outcomes. The surgical treatment involves caesarean section and hysterectomy, with additional interventions for bladder invasion in percreta cases.

Background: Prior prelabor cesarean delivery (CD) was associated with an increase in the risk of placenta previa (PP) in a second delivery, whether it may impact postpartum hemorrhage (PPH) independent of abnormal placentation. This study aimed to assess the risk of PPH stratified by abnormal placentation following a first CD before the onset of labor (prelabor) or intrapartum CD.Methods: This multicenter, historical cohort study involved singleton, pregnant women at 28 weeks of gestation or greater with a CD history between January 2017 and December 2017 in 11 public tertiary hospitals within 7 provinces of China. PPH was analyzed in the subsequent pregnancy between women with prior prelabor CD and women with intrapartum CD. Furthermore, PPH was analyzed in pregnant women stratified by complications with PP alone [without placenta accreta spectrum (PAS) disorders], complications with PP and PAS, complications with PAS alone (without PP), and normal placentation. We performed multivariate logistic regression to calculate adjusted odds ratios (aOR) and 95% CI controlling for predefined covariates.Results: Out of 10,833 pregnant women, 1,197 (11%) women had a history of intrapartum CD and 9,636 (89%) women had a history of prelabor CD. Prior prelabor CD increased the risk of PP (aOR 1.91, 95% CI 1.40–2.60), PAS (aOR 1.68, 95% CI 1.11–2.24), and PPH (aOR 1.33, 95% CI 1.02–1.75) in a subsequent pregnancy. After stratification by complications with PP alone, PP and PAS, PAS alone, and normal placentation, prior prelabor CD only increased the risk of PPH (aOR 3.34, 95% CI 1.35–8.23) in a subsequent pregnancy complicated with PP and PAS.Conclusion: Compared to intrapartum CD, prior prelabor CD increased the risk of PPH in a subsequent pregnancy only when complicated by PP and PAS.

Implantation and placentation at the normal site are critical for a successful pregnancy. Many complications associated with pregnancy, which manifest late in pregnancy, such as preeclampsia and preterm labour, have been reported to have origins early during pregnancy with abnormalities in implantation and placental development. Placental abnormalities result from impaired embedding of the placenta in the endometrium, encompassing a wide range of placental pathologies associated with high maternal morbidity and mortality. Pregnancy-related complications such as Postpartum Haemorrhage (PPH) and hysterectomy have been closely linked to the Placenta Accreta Spectrum (PAS). PAS refers to the aberrant and invasive implantation of the placenta into the myometrium. Invasiveness in placenta accreta is marginal, followed by placenta increta (partial), placenta percreta (total), and placenta previa (covering the cervix). Here, the authors present a unique case report of an antenatal woman with antepartum haemorrhage, placenta previa, and placenta accreta at the previous Lower Segment Caesarean Section (LSCS) scar site, with massive PPH at 35 weeks, who benefited from an emergency LSCS with bilateral uterine and internal iliac artery ligation procedure, resulting in a life-saving outcome. The most common risk factors for PAS include prior caesarean section and curettage. The adhered placenta can lead to pelvic bleeding and necessitate an emergency hysterectomy. Therefore, it poses unique diagnostic and treatment issues, with the majority of cases requiring preterm termination of pregnancy.

Extensive fundal placenta accreta spectrum (PAS) in a nulliparous patient with an unscarred uterus and systemic lupus erythematosus (SLE) necessitating cesarean hysterectomy at delivery