Risk Of Placenta Accreta Spectrum Research Articles

The Role of Transvaginal Ultrasound in the Third-Trimester Evaluation of Patients at High Risk of Placenta Accreta Spectrum at Birth

The Role of Transvaginal Ultrasound in the Third-Trimester Evaluation of Patients at High Risk of Placenta Accreta Spectrum at Birth

Placenta accreta spectrum in the second trimester: a clinical conundrum in procedural abortion care

Given the limitations in perioperative management strategies available at freestanding abortion clinics, abortion providers must commonly discern which patients are too complicated for procedural abortions at their center and must be referred for a hospital-based abortion. The need to transition from freestanding clinics to hospital-based abortion care can lead to delays in completing an abortion and significant social, economic, and psychological repercussions for the pregnant individual. One significant clinical problem that exemplifies the issue of who can be safely taken care of at a freestanding abortion clinic is when the placenta accreta spectrum is suspected. Placenta accreta spectrum is one of the major contributors to maternal morbidity and mortality in the United States, requiring coordinated multidisciplinary management to ensure the safest outcome for the pregnant individual. In this Clinical Opinion, we review the literature focused on identifying individuals at risk for placenta accreta spectrum >14+0 weeks gestation, delineate an algorithm to improve the frequency of timely referrals to hospital-based abortion providers, and propose next steps for future training goals and research on placenta accreta spectrum in the second trimester between complex family planning and maternal-fetal medicine subspecialists.

Development and validation of a nomogram for predicting placenta accreta spectrum in pregnancies with one previous cesarean delivery.

This study aimed to develop and validate a prenatal nomogram to predict the risk of placenta accreta spectrum (PAS) in women with one previous cesarean delivery. This retrospective study enrolled 5157 pregnant women with one previous cesarean delivery in China from January 2021 to January 2023. The nomogram was developed from a training cohort of 3612 pregnant women and tested on a validation cohort of 1545 pregnant women. Multivariate regression analysis was performed using the minimum value of the Akaike information criterion to select prognostic factors that can be included in the nomogram. We evaluated the nomogram by the area under the receiver operating characteristic (ROC) curve, calibration curves, and the decision curve analysis (DCA). PAS occurred in 199 (5.51%) and 80 (5.18%) patients in the training and validation cohorts, respectively. Backward stepwise algorithms in the multivariable logistic regression model determined abortion, hypertensive disorders complicating pregnancy, fetal position, and placenta previa as relevant PAS predictors. The area under the ROC curve for the nomogram was 0.770 (95% confidence interval [CI] 0.733-0.807) and 0.791 (95% CI 0.730-0.853) for the training and validation cohorts, respectively. The calibration curves indicated that the nomogram's prediction probability was consistent with the actual probability. The DCA curve revealed that the nomogram has potential clinical benefit. A prenatal nomogram was developed for PAS in our study, which helped obstetricians determine potential patients with PAS and make sufficient preoperative preparation to reduce maternal and neonatal complications.

Trimester-specific diagnostic accuracy of ultrasound for detection of placenta accreta spectrum: systematic review and meta-analysis.

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. 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. 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%)). 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.

A sonographic endometrial thickness

BackgroundThe prevalence of placenta accreta spectrum (PAS), a potentially life-threatening condition, has exhibited a significant global rise in recent decades. Effective screening methods and early identification strategies for PAS could enable early treatment and improved outcomes. Endometrial thickness (EMT) plays a crucial role in successful embryo implantation and favorable pregnancy outcomes. Extensive research has been conducted on the impact of EMT on assisted reproductive technology cycles, specifically in terms of pregnancy rates, live birth rates, and pregnancy loss rates. However, limited knowledge exists regarding the influence of EMT on PAS. ObjectiveThis study aims to evaluate association between pre-implantation EMT and the occurrence of PAS in women undergoing assisted reproductive technology cycles. Study DesignA total of 4637 women who had not undergone prior caesarean section, conceived by in vitro fertilization or intracytoplasmic sperm injection embryo transfer treatment and subsequently delivered at the Third Affiliated Hospital of Guangzhou Medical University between January 2008 to December 2020 were included in this study. To explore the relationship between EMT and PAS, we employed smooth curve fitting, threshold effect, and saturation effect analysis. Multivariate logistic regression analysis was performed to evaluate the independent association between EMT and PAS while adjusting for potential confounding factors. Propensity score matching (PSM) was performed to reduce the influence of bias and unmeasured confounders. Furthermore, we employed causal mediation effect analysis to investigate the mediating role of EMT in the relationship between gravidity and ovarian stimulation protocol and the occurrence of PAS. ResultsAmong the 4637 women included in this study, pregnancies with PAS (159, 3.4%) had significantly thinner EMT (non-PAS 10.08±2.04 vs PAS 8.88±2.21 mm，P<0.001) during the last ultrasound before embryo transfer. By smooth curve fitting, the saturated effect was found on EMT and PAS, with an inflection point at 10.9mm. Then the EMT was divided into four groups: ≤7mm, >7 to≤10.9mm, >10.9 to≤13mm, >13mm, and the absolute rates of PAS in each group was 11.91%, 3.73%, 1.35%, and 2.54%, respectively. When compared to women with an EMT ranging from between 10.9-13mm, the odds of PAS increased from adjusted odds ratio (aOR) of 2.27 (95% CI, 1.33-3.86) for EMT ranging from 7-10.9mm to aOR of 7.15 (95% CI, 3.73-13.71) for EMT <7mm after adjusting for potential confounding factors. Placenta previa remained as an independent risk factor for PAS (aOR, 11.80; 95% CI, 7.65-18.19). Moreover, EMT <7mm was still an independent risk factor for PAS (aOR, 3.91; 95% CI, 1.57-9.73) in the matched cohort after PSM. Causal mediation analysis revealed that approximately 63.9% of the total effect of gravidity and 18.6% of the total effect of ovarian stimulation protocol on PAS were mediated by the EMT. ConclusionsThe findings from our study indicate that thin EMT is an independent risk factor for PAS in women without prior caesarean section undergoing assisted reproductive technology treatment. The clinical significance of this risk factor is slightly lower than placenta previa. Furthermore, our results demonstrate that EMT plays a significant mediating role in the relationship between gravida or ovarian stimulation protocol and PAS.

Evaluation of maternal serum VEGF, TNF-alpha, IL-4, and IL-10 levels in differentiating placenta accreta spectrum from isolated placenta previa

ObjectiveOur study aimed to differentiate patients with placenta accreta spectrum (PAS) from those with placenta previa (PP) using maternal serum levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4), and IL-10. MethodsThe case group consisted of 77 patients with placenta previa, and the control group consisted of 90 non-previa pregnant women. Of the pregnant women in the case group, 40 were diagnosed with PAS in addition to placenta previa and 37 had placenta previa with no invasion. The maternal serum VEGF, TNF-alpha, IL-4, and IL-10 levels were compared between the case and control groups. Then the success of these markers in differentiating between PP and PAS was evaluated. ResultsWe found the VEGF, TNF-alpha, and IL-4 levels to be higher and the IL-10 level to be lower in the case group compared to the control group (p < 0.001). We observed a statistically significantly lower IL-10 level in the patients with PAS than those with PP (p = 0.029). In the receiver operating characteristic analysis, the optimal cut-off of IL-10 in the detection of PAS was 0.42 ng/mL). In multivariate analysis, the risk of PAS was significant for IL-10 (odds ratio (OR) 0.45, 95 % confidence interval (CI) 0.25–0.79, p = 0.006) and previous cesarean section (OR 2.50, 95 % Cl 1.34–4.66, p = 0.004). The model’s diagnostic sensitivity and specificity, including previous cesarean section, preoperative hemoglobin (Hb), TNF-alpha, and IL-10 were 75 % and 72.9 %, respectively. ConclusionThe study showed that the IL-10 level was lower in patients with PAS than in those with PP. A statistical model combining risk factors including previous cesarean section, preoperative Hb, TNF-alpha, and IL-10 may improve clinical diagnosis of PAS in placenta previa cases. Cytokines may be used as additional biomarkers to the clinical risk factors in the diagnosis of PAS.

Risk of placenta accreta spectrum following myomectomy: a nationwide cohort study

BackgroundWhether myomectomy increases the risk of placenta accreta spectrum (PAS) in the following pregnancies remains controversial. ObjectiveThis study aimed to investigate the effect of myomectomy on the risk of placenta accreta spectrum in the following pregnancies. Different methods of myomectomy on the risk of placenta accreta spectrum were also explored. Study designA nationwide cohort study was conducted using data from the Taiwan National Health Insurance Research Database including all pregnant patients in Taiwan who gave birth between January 2008 and December 2017. A 1:1 propensity-score estimation matching was performed for the analysis of myomectomy on the risk of placenta accreta spectrum. Among pregnant patients who received myomectomy, different methods of myomectomy on the risk of placenta accreta spectrum were compared with control group. ResultsAmong the 1,371,458 pregnant patients in this study, there were 11,255 pregnant patients who had history of myomectomy. The risk of PAS in pregnant patients with history of myomectomy was higher than pregnant patients without history of myomectomy (incidence 0.96% vs. 0.20%, adjusted odds ratio 2.28, 95% CI 1.85-2.81, p<0.01). Among pregnant patients with history of myomectomy, 5,045 (46.87%) pregnant patients received laparotomic myomectomy, 3,973 (36.93%) received laparoscopic myomectomy, and 1,742 (16.20%) received hysteroscopic myomectomy. The incidence of PAS in the hysteroscopic group was higher than that in the laparotomic group or the laparoscopic group (1.89%, 0.71%, and 0.81% respectively, p<0.05 vs. the hysteroscopic group). The adjusted odds ratio for PAS was 3.88 (95% CI 2.68-5.63) in the hysteroscopic group compared to subjects without history of myomectomy (p<0.05). ConclusionMyomectomy, especially hysteroscopic myomectomy, is associated with increased risk of PAS in the subsequent pregnancy.

The Impact of Preoperative Ultrasound and Intraoperative Findings on Surgical Outcomes in Patients at High Risk of Placenta Accreta Spectrum

(BJOG. 2023;130:42–50) When placental villous tissue abnormally attaches to the uterine wall it is known as placenta accreta spectrum (PAS). A large number of PAS cases are seen in the setting of placenta previa and previous cesarean delivery (CD). Removing placental villous tissue at delivery typically results in hemorrhaging. This hemorrhaging has been proven to be reduced when PAS is caught before delivery. Studies show that PAS is missed before delivery in over 50% of cases. This study aimed to determine how preoperative ultrasound can help to detect PAS in patients prior to delivery.

Associations of characteristics of previous induced abortion with different grades of current placenta accreta spectrum disorders

Objective Induced abortion could increase the risk of placenta accreta spectrum (PAS) in the next pregnancy. We aimed to explore the associations between characteristics of previous induced abortion and grades of current PAS. Methods A retrospective case-control study was performed in eligible pregnant women with PAS between January 2014 and June 2022. Data collected included demographics, obstetric characteristics, and information on previous induced abortion. Results The study included 211 pregnant women, with 51 and 160 in the invasive (placenta increta or percreta) and adherence (placenta creta) PAS groups, respectively. The risk of invasive PAS was 14.3-fold higher in patients with abnormal vaginal bleeding after abortion (odds ratio = 14.3, 95% confidence interval 5.6–36.4, p < .01) than those without abnormal vaginal bleeding and approximately 5.8-fold higher in patients with the last induced abortion ≥5 years ago than those within 5 years (odds ratio = 5.8, 95% confidence interval 2.2–15.2, p < .01). The risk of invasive PAS was 13.4-fold higher in patients with placenta attached to uterine cornu than patients with the placenta attached to uterine wall (odds ratio = 17.5, 95% confidence interval 5.5–55.5, p < .01). The number of previous induced abortions, hospital grades, and gestational age at abortion were not different between two groups. Conclusion In pregnant women with a history of induced abortion, abnormal vaginal bleeding after induced abortion and prolonged duration after the last induced abortion increased the risk for invasive PAS in the current pregnancy. The number of previous induced abortions and gestational age at abortion had no relation to the grades of PAS.

Assessment of placenta accreta spectrum at vaginal birth after cesarean delivery

Previous cesarean delivery is a risk factor for developing placenta accreta spectrum in a subsequent pregnancy and patients with antenatally suspected placenta accreta spectrum frequently undergo planned cesarean hysterectomy. There is a paucity of data regarding unsuspected placenta accreta spectrum among patients undergoing trial of labor after cesarean delivery for attempted vaginal birth after cesarean delivery. This study aimed to investigate the incidence, characteristics, and delivery outcomes of patients with placenta accreta spectrum diagnosed at the time of vaginal birth after cesarean delivery. The Healthcare Cost and Utilization Project's National Inpatient Sample was retrospectively queried to examine 184,415 patients with a history of low transverse cesarean delivery who had vaginal delivery in the current index hospital admission between 2017 and 2020. Those with placenta previa, previous vertical cesarean delivery, other uterine scars, and uterine rupture were excluded. This study identified placenta accreta spectrum cases using the World Health Organization International Classification of Disease, Tenth Revision, codes of O43.2. Coprimary outcomes were (1) the incidence rate of placenta accreta spectrum at vaginal birth after cesarean delivery; (2) clinical and pregnancy characteristics related to placenta accreta spectrum, assessed with multivariable binary logistic regression model; and (3) delivery outcomes associated with placenta accreta spectrum by fitting propensity score adjustment. The secondary outcome was to conduct a systematic literature review using 3 public search engines (PubMed, Cochrane, and Scopus). Data on incidence rate and maternal morbidity related to placenta accreta spectrum at vaginal birth after cesarean delivery were evaluated. The incidence rate of placenta accreta spectrum at vaginal birth after cesarean delivery was 8.1 per 10,000 deliveries. Most placenta accreta spectrum cases were placenta accreta (83.3%). In a multivariable analysis, older maternal age, tobacco use, preeclampsia, multifetal pregnancy, fetal anomaly, preterm premature rupture of membrane, chorioamnionitis, low-lying placenta, and preterm delivery were associated with an increased risk of placenta accreta spectrum (all, P<.05). Of these factors, low-lying placenta had the largest odds for placenta accreta spectrum (526.3 vs 7.3 per 10,000 deliveries; adjusted odds ratio, 35.02; 95% confidence interval, 18.19-67.42). Patients in the placenta accreta spectrum group were more likely to have postpartum hemorrhage (80.0% vs 5.5%), blood product transfusion (23.3% vs 1.0%), shock or coagulopathy (20.0% vs 0.2%), and hysterectomy (43.3% vs <0.1%) than those without placenta accreta spectrum (all, P<.001). In a systematic literature review, a total of 212 studies were screened, and none of these studies examined the incidence and morbidity of placenta accreta spectrum at vaginal birth after cesarean delivery. This nationwide assessment suggests that although placenta accreta spectrum with vaginal birth after cesarean delivery is uncommon (1 of 1229 cases), the diagnosis of placenta accreta spectrum at vaginal birth after cesarean delivery is associated with significant maternal morbidity. In addition, the data suggest that low-lying placenta in the setting of previous low transverse cesarean delivery warrants careful evaluation for possible placenta accreta spectrum before a trial of labor.

Basal Plate Myofibers and the Risk of Placenta Accreta Spectrum in the Subsequent Pregnancy: A Large Single-Center Cohort.

We aimed to evaluate whether there is a significant association between a placental pathology diagnosis basal plate myofibers (BPMF) in an index pregnancy with placenta accreta spectrum (PAS) in the subsequent pregnancy. We conducted a retrospective nested cohort study of all cases with a histopathological finding of BPMF between August 2012 and March 2020 at a single tertiary referral center. Data were collected for all subjects (cases and controls) with at least two consecutive pregnancies (the initial index pregnancy and at least one subsequent pregnancy) accompanied by a concomitant record of histopathological study of the placenta at our center. The primary outcome was pathologically confirmed PAS in the subsequent pregnancy. Data are presented as percentage or median, interquartile range accordingly. A total of n = 1,344 participants were included, of which n = 119 (index cases) carried a contemporaneous histopathological diagnosis of BPMF during the index pregnancy and n = 1,225 did not (index controls). Among the index cases, patients with BPMF were older (31.0 [20, 42] vs. 29.0 [15, 43], p < 0.001), more likely to have undergone in vitro fertilization (IVF) for conception (10.9 vs. 3.8%, p = 0.001) and were of a more advanced gestational age at delivery (39.0 [25, 41] vs. 38.0 [20, 42], p = 0.006). In the subsequent pregnancy, the rate of PAS was significantly higher among the BPMF index cases (6.7 vs. 1.1%, p < 0.001). After adjusting for maternal age and IVF, a histopathological diagnosis of BPMF in an index pregnancy was shown to be a significant risk factor for PAS in the subsequent gestation (hazard ratio: 5.67 [95% confidence interval: 2.28, 14.06], p < 0.001). Our findings support that a histopathological diagnosis of BPMF is an independent risk factor for PAS in the subsequent pregnancy. · BPMF may indicate morbid adherence of placenta.. · Patients with BPMF were older and more likely to have undergone IVF for conception.. · The BPMF in the current pregnancy is an independent risk factor for PAS in the subsequent pregnancy..

Imaging the Uterus in Placenta Accreta Spectrum Disorder.

Antenatal diagnosis of placenta accreta spectrum (PAS) improves maternal and neonatal outcomes by allowing for multidisciplinary planning and preparedness. Ultrasound is the primary imaging tool. Simplification and standardization of placental evaluation and reporting terminology allows improved communication and understanding between teams. Prior to 10 weeks of gestation, gestational sac position and least myometrial thickness surrounding the gestational sac help PAS diagnosis very early in pregnancy. Late first-, second-, and third-trimester evaluation includes comprehensive evaluation of the placenta, transabdominal and transvaginal with partially full maternal urinary bladder, and by color Doppler. Subsequently, the sonologist should indicate whether the evaluation was optimal or suboptimal; the level of suspicion as low, moderate, or high; and the extent as focal, global, or extending beyond the uterus. Other complementary imaging modalities such as 3D-power Doppler ultrasound, magnetic resonance imaging (MRI), and vascular topography mapping strive to improve antenatal placental evaluation but remain investigational at present. KEY POINTS: · Antenatal imaging, primarily using ultrasound with partially full maternal urinary bladder, is an essential means of evaluation of those at risk for PAS.. · Simplification and standardization of placental evaluation and reporting will allow improved communication between the multidisciplinary teams.. · Gestational sac location prior to 10 weeks of gestation and four markers after that (placental lacunae and echostructure, myometrial thinning, hypoechoic zone with or without bulging between placenta and myometrium, and increased flow on color Doppler)..

The Need for Presurgical Evaluation for Placenta Accreta Spectrum.

Staging or grading of placenta accreta spectrum has historically relied on histopathologic evaluation of placental and uterine specimens. This approach has limited utility, since it is retrospective in nature and does not allow for presurgical planning. Here, we argue for a paradigm shift to use of clinical and imaging characteristics to define the presurgical stage. We summarize past attempts at staging, and define a new data-driven approach to determining the stage prior to delivery. Use of this model may help hospitals direct patients to the most appropriate level of care for workup and management of placenta accreta spectrum. KEY POINTS: · Staging systems that rely on histopathologic grade (accreta, increta, percreta) are unhelpful in antenatal planning for placenta accreta spectrum.. · Past attempts at pre-delivery (pre-surgical) staging have failed to account for key factors that contribute to risk and morbidity.. · We developed a data-driven model that could be easily incorporated as a decision aid into clinical practice to help clinicians decide an individual patient's risk for placenta accreta spectrum..

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

Transvaginal ultrasound imaging has become an essential tool in the prenatal evaluation of the lower uterine segment and anatomy of the cervix, but there are only limited data on the role of transvaginal ultrasound in the management of patients at high risk of placenta accreta spectrum at birth. This study aimed to evaluate the role of transvaginal sonography in the third trimester of pregnancy in predicting outcomes in patients with a high probability of placenta accreta spectrum at birth. This was a retrospective analysis of prospectively collected data of patients presenting with a singleton pregnancy and a history of at least 1 previous cesarean delivery and patients diagnosed prenatally with an anterior low-lying placenta or placenta previa delivered electively after 32 weeks of gestation. All patients had a least 1 detailed ultrasound examination, including transabdominal and transvaginal scans, within 2 weeks before delivery. Of note, 2 experienced operators, blinded to the clinical data, were asked to make a judgment on the likelihood of placenta accreta spectrum as a binary, low or high-probability of placenta accreta spectrum, and to predict the main surgical outcome (conservative vs peripartum hysterectomy). The diagnosis of accreta placentation was confirmed when one or more placental cotyledons could not be digitally separated from the uterine wall at delivery or during the gross examination of the hysterectomy or partial myometrial resection specimens. A total of 111 patients were included in the study. Abnormal placental tissue attachment was found in 76 patients (68.5%) at birth, and histologic examination confirmed superficial villous attachment (creta) and deep villous attachment (increta) in 11 and 65 cases, respectively. Of note, 72 patients (64.9%) had a peripartum hysterectomy, including 13 cases with no evidence of placenta accreta spectrum at birth because of failure to reconstruct the lower uterine segment and/or excessive bleeding. There was a significant difference in the distribution of placental location (X2=12.66; P=.002) between transabdominal and transvaginal ultrasound examinations, but both ultrasound techniques had similar likelihood scores in identifying accreta placentation that was confirmed at birth. On transabdominal scan, only a high lacuna score was significantly associated (P=.02) with an increased chance of hysterectomy, whereas on transvaginal scan, significant associations were found between the need for hysterectomy and the thickness of the distal part of the lower uterine segment (P=.003), changes in the cervix structure (P=.01), cervix increased vascularity (P=.001), and the presence of placental lacunae (P=.005). The odds ratio for peripartum hysterectomy were 5.01 (95% confidence interval, 1.25-20.1) for a very thin (<1-mm) distal lower uterine segment and 5.62 (95% confidence interval, 1.41-22.5) for a lacuna score of 3+. Transvaginal ultrasound examination contributes to both prenatal management and the prediction of surgical outcomes in patients with a history of previous cesarean delivery with and without ultrasound signs suggestive of placenta accreta spectrum. Transvaginal ultrasound examination of the lower uterine segment and cervix should be included in clinical protocols for the preoperative evaluation of patients at risk of complex cesarean delivery.

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

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. 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 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. 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.

Placenta Percreta with Bladder Invasion: Case Report

Background: Placenta previa with bladder invasion is an uncommon and serious pathology, involving the maternal prognosis. However, as the rate of cesareans has increased, the disease has become more common. Case presentation: We present the case of placenta previa percreta in 34 weeks of amenorrhea, gravida 2 para 1, with a history of a single caesarean section 5 years prior. Initially admitted for threat of premature delivery, we found a totally covering placenta previa with accretization sign and suspicion of bladder invasion. Abdomino pelvic MRI confirmed the diagnosis of placenta previa percreta. During monitoring, the patient presented an acute fetal distress requiring an emergency fetal extraction. She underwent a caesarean section for fetal rescue followed by a total hysterectomy requiring the removing of the anterior part of the bladder. Conclusion: With a rising rate of cesarean sections, the risk of placenta accreta spectrum is increasing as well. Obstetricians and clinicians should be vigilant in prenatal diagnosis, especially if the risk factors are present. Multidisciplinary approach for preoperative, intraoperative and postoperative management can significantly improve maternal and fetal prognosis.

Impact of a standardized multidisciplinary protocol for placenta accreta spectrum on blood bank services

To assess the impact of a standardized multidisciplinary protocol for managing patients with placenta accreta spectrum (PAS) on the utilization of blood bank services. We performed a retrospective cohort study of all pregnant women managed at our center between January 2013 and October 2019 for confirmed or suspected PAS disorders. We compared the demographic and clinical characteristics of the patients and the utilization of blood bank services, including dispensed, transfused, and wasted blood components products, before (T1) and after (T2) the implementation of a standardized multidisciplinary protocol. This protocol focused on increased surveillance and readiness for patients at risk for PAS, standardization of surgery, anesthesia and transfusion practices, selective embolization of pelvic arteries in patients with abnormally invasive placenta, intraoperative blood salvage, and robust treatment of anemia antenatally. Univariate analysis was performed using unpaired t, Mann-Whitney, chi-square, and Fisher's exact tests as appropriate. The patients' characteristics in T1 and T2 were comparable (Table1). In T2, 79% of the patients were managed according to the protocol. The number of blood products dispensed from the blood bank, particularly RBCs, increased during T2. (Table 2). In contrast, fewer RBCs and FFPs were transfused in T2. There was no significant difference in dispensed or transfused platelet and cryoprecipitate units. The number of wasted blood products was small and did not significantly change. The decreased transfusion of RBC and FFP was the result of a decline in peripartum blood loss (median, 800 vs.1550 ml, p< . 001) and the risk for massive blood loss (RR: 0.16, 95% CI: 0.03 to 0.92, p=.04) and stage 3 postpartum hemorrhage (RR: 0.37, 95% CI: 0.17 to 0.75, p=.009). The standardized multidisciplinary protocol for PAS increased the workload of our blood bank due to greater dispensation of blood products but resulted in fewer RBC and FFP transfusions parallel to a decline in catastrophic hemorrhage.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Normal placental structural anatomy: ultrasound and doppler features elucidated with US-MR image fusion and ferumoxytol-enhanced MRI.

To elucidate ultrasound features of normal placental anatomy through correlation of gray-scale and ultrasound Doppler with ferumoxytol-enhanced MRI features using US-MR image fusion. All patients referred to MR for ultrasound findings worrisome for PAS (placenta accreta spectrum) were included in this retrospective study. MR studies included a ferumoxytol-enhanced T1-weighted MRI. Ultrasound imaging included gray-scale, color Doppler, power Doppler, and spectral Doppler techniques. After the MR, US-MRI fusion was performed by co-registering a MR acquisition to real-time US, which allowed precise, point-to-point correlation of placental features. Fourteen patients at risk for PAS were studied using the US-MR image fusion. At delivery, there were six cases without PAS (gestational age range: 24weeks 3days to 34weeks 0days), and these composed the study cohort. Placental features that were on high signal intensity on post-ferumoxytol acquisitions represent spaces with maternal blood flow and corresponded to hypoechoic areas on ultrasound created by a paucity of reflective interfaces (villi). Color and spectral Doppler allowed the separation of maternal and fetal circulations in individual perfusional domains and demonstrated spiral artery inflow, circulation around the villous tree, and return of blood flow to the basal plate. Recognizable histopathologic features by ultrasound included the central cavity, villous tree, and venous return channels. Internal placental architecture can be discerned on ultrasound. This anatomy can be correlated and confirmed with ferumoxytol-MR through US-MR fusion. Understanding this structural anatomy on ultrasound could serve as a basis to identify normal and abnormal placental features.

The impact of preoperative ultrasound and intraoperative findings on surgical outcomes in patients at high risk of placenta accreta spectrum.

To assess whether preoperative ultrasound imaging and intraoperative features predict surgical outcomes in patients at high risk for placenta accreta spectrum (PAS). Cohort study. Cairo University Maternity, Egypt. Pregnant patients with one or more prior caesarean deliveries presenting with a low-lying/placenta praevia with or without PAS confirmed by histopathology. Logistic regression and multivariable analyses. Need for primary caesarean hysterectomy, numbers of red blood cell (RBC) units transfused and patients requiring transfusion of >5units. Ninety consecutive records were reviewed, including 58 (64.4%) PAS cases. Sixty (66.7%, 95% confidence interval (CI) 56-76) required hysterectomy. Odds of hysterectomy were significantly (p= 0.005) increased with complete praevia. Significantly higher odds of hysterectomy were associated with subplacental hypervascularity (7.23, 95% CI 2.72-19.2, p< 0.001), lacunar scores 2+ and 3+ (12.6, 95% CI 4.15-38.5, p< 0.001), lacunar feeder vessels (5.69, 95% CI 1.77-18.3, p= 0.004) or bridging vessels (2.00, 95% CI 1.29-3.10, p= 0.002) on ultrasound, and increased lower segment vascularization at laparotomy (5.42, 95%CI 2.09-14.1, p= 0.001). Transfusion >5 RBC units was associated with number of lacunae (odds ratio [OR] 1.48, 95% CI 1.14-1.93, p= 0.004) and presence of feeder vessels (OR 1.62, 95% CI 1.24-2.11, p= 0.001). The multivariable analysis indicated that parity, placental location and PAS were significantly (p= 0.007; p= 0.01; p< 0.001, respectively) associated with hysterectomy. Preoperative ultrasound imaging can assist in triaging and counselling patients regarding the odds of PAS, intraoperative blood losses and need for hysterectomy, and intraoperative features can assist the surgeon in evaluating the need for multidisciplinary support.

Separation sign: novel ultrasound sign for ruling out diagnosis of placenta accreta spectrum.

ABSTRACTObjectiveTo assess the performance of the ‘separation sign’ as a predictor of normal placental separation in a large cohort of women at risk for placenta accreta spectrum (PAS) and in a high‐risk subgroup with placenta previa or anterior low‐lying placenta and at least one previous Cesarean delivery.MethodsThis was a prospective study of women at risk for PAS referred to a specialist clinic at between 22 and 38 weeks' gestation. All women underwent ultrasound assessment for the presence of the separation sign, which detects the difference in elasticity between the myometrium and the placenta, characterized by different rates of rebound after an ultrasound probe is used to apply pressure over the uteroplacental interface. When the sign is positive, the placenta appears to move relative to the myometrium, leading to the appearance or enhancement of the clear zone. The predictive performance of the separation sign for normal spontaneous placental separation at delivery was assessed.ResultsOf the 194 included women, 163 had a positive separation sign, all of whom went on to have normal placental separation at delivery. Of the 24 women with a negative separation sign, three (12.5%) had normal placental separation and 21 (87.5%) were diagnosed with PAS. This yielded a sensitivity of 98.2% (95% CI, 94.8–99.6%) and specificity of 100% (95% CI, 83.9–100%). In the high‐risk cohort (n = 35), a positive separation sign remained a reliable predictor of normal placental separation, with a positive predictive value of 100%, sensitivity of 88.9% (95% CI, 65.3–98.6%) and specificity of 100% (95% CI, 80.5–100%).ConclusionsThe separation sign could be a useful tool in women considered to be at risk for PAS, as it can facilitate the prediction of normal placental separation at delivery. This may prevent overtreatment, the associated iatrogenic morbidity and unnecessary allocation of clinical resources. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.