An ultrasonic scoring system to predict the prognosis of placenta accreta: A prospective cohort study

A prediction model based on MRI and ultrasound to predict the risk of PAS in patient with placenta previa

INTRODUCTION

To investigate the risk factors affecting patients with placenta previa (PP) and to construct an effective prediction model for the severity of PAS in PP.

METHODS

A total of 240 pregnant women with PP were enrolled in this study. An MRI+Ultrasound-based model was developed to classify patients into placental implantation and non-placental implantation groups. Multivariate nomograms were created based on imaging features. The model was evaluated using Receiver Operating Characteristic (ROC) curve analysis. The predictive accuracy of the nomogram was assessed through calibration plots and decision curve analysis.

RESULTS

The MRI+Ultrasound-based prediction model demonstrated favorable discrimination between the placental implantation and non-placental implantation groups. The calibration curve exhibited agreement between the estimated and actual probability of placental implantation. Additionally, decision curve analysis indicated a high clinical benefit across a wide range of probability thresholds. The Area under the ROC curve (AUC) was 0.911 (95 % CI: 0.76-0.947), with a sensitivity of 88.40 % and specificity of 88.10 %.

CONCLUSION

The MRI+Ultrasound-based prediction model could be a valuable tool for preoperative prediction of the percentage of implantation. Our study enables obstetricians to conduct more adequate preoperative evaluations.

Quantifying placenta accreta spectrum severity and its associated blood loss: a novel transvaginal ultrasound scoring system

BACKGROUND

Hemorrhage associated with placenta accreta spectrum (PAS) is a leading cause of maternal morbidity and mortality. Estimating blood loss in these individuals is a critical component of comprehensive preoperative planning.

OBJECTIVE

A semiquantitative score based on transvaginal ultrasound was developed and tested to predict PAS, estimate its severity, and blood loss in individuals with clinical and ultrasound evidence suggesting PAS.

STUDY DESIGN

A secondary analysis was conducted of prospectively collected data from a quaternary center of patients with suspected accreta on 2D ultrasound and clinical suspicion. A predetermined scoring system was applied based on three components: (1) uterine wall (score 0: no loss of hypo-translucent uterine wall with overlying placenta in the lower uterine segment; 1: loss of hypo-translucent <3-cm defect; 2: 3-6-cm defect; and 3: >6-cm defect); (2) arterial vascularity at the uterine wall defect (score 0: no vessels observed; 1: 1-2 vessels over the defect; 2: 3-5 vessels; and 3: >5 vessels); and (3) cervical involvement (score 0: normal cervical length without previa; 1: previa with normal cervical length; 2: short cervix with previa, minimal vascularity and small lacunae; 3: short cervix with previa, increased vascularity and large lacunae). Each patient's three domain scores determined a cumulative, final score of 0-9. Patients were managed at the discretion of a multi-disciplinary team and patient's preference among the following options: cesarean delivery with placenta removal, cesarean delivery with placenta in-situ (conservative) with or without delayed hysterectomy, or cesarean hysterectomy. The frequency of different degrees of placental invasion per pathology examination per score unit was registered. Multiple linear regression analysis was performed for association of blood loss according to score adjusted by risk factors for PAS.

RESULTS

A total of 73 patients were evaluated. All 11 patients who had a score of 0 had cesarean delivery with placenta removal without evidence of intraoperative PAS, thus resulting in a 100% negative predictive value. The remaining 62 had scores between 1 and 9. Among patients with scores 0-3 (n=20), only one had intraoperative PAS, yielding a negative predictive value of 97%. Higher scores were associated with severe PAS forms (r=0.301, P=.02). Based on the associations between PAS scores, clinical correlation, and blood loss, we divided patients into four categories: Category 0: PAS score 0; Category 1: scores 1-3; Category 2: scores 4-6; and Category 3: scores 7-9. The median blood loss in Category 0=635±352 mL, Category 1=634±599 mL, Category 2=1549±1284 mL, and Category 3=1895±2106 mL (P<.001). On multivariable analysis, Category 2 (β=0.97, P<.01) and Category 3 (β=1.26, P<.003) were associated with significantly greater blood loss than Category 0, irrespective of type of surgery.

CONCLUSION

The transvaginal ultrasound score separates groups at low risk (Category 0) and at higher risk of PAS (Categories 1-3). Categories 1-3 may provide important clinical information to estimate the risk of severe forms of PAS and of blood loss during surgery. VIDEO ABSTRACT.

Clinical-sonographic scores for the screening of placenta accreta spectrum: a systematic review and meta-analysis

OBJECTIVE

Clinical-sonographic scoring systems combining clinical features and ultrasound imaging markers have been proposed for the screening of placenta accreta spectrum, but their usefulness in different settings remains limited. This study aimed to assess and compare different clinical-sonographic score systems applied from mid-pregnancy for the prenatal evaluation of patients at risk of placenta accreta spectrum at birth.

DATA SOURCES

PubMed/MEDLINE, Google Scholar, and Embase were searched between October 1982 and October 2022 to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Observational studies providing data on the use of a combined clinical-ultrasound score system applied from mid-pregnancy for the prenatal evaluation of placenta accreta spectrum were included.

METHODS

Study characteristics were evaluated by 2 independent reviewers using a predesigned protocol registered on PROSPERO (CRD42022332486). Heterogeneity among studies was analyzed with Cochran's Q-test and I2 statistics. Statistical heterogeneity was quantified by estimating the variance between the studies using I2 statistics. The area under the receiver operating characteristic curve of each score and their summary receiver operating characteristic curves were calculated with sensitivity and specificity, and the integrated score of the summaries of the receiver operating characteristic curves of all sonographic markers was calculated. Forest plots were used to develop the meta-analysis of each sonographic marker and for the integrated sonographic score.

RESULTS

Of 1028 articles reviewed, 12 cohorts and 2 case-control studies including 1630 patients screened for placenta accreta spectrum by clinical-ultrasound scores met the eligibility criteria. A diagnosis of placenta accreta spectrum was reported in 602 (36.9%) cases, for which 547 (90.9%) intraoperative findings and/or histopathologic data were described. A wide variation was observed among the studies in reported sensitivities and specificities and in thresholds used for the identification of patients with a high probability of placenta accreta spectrum at birth. The summaries of the areas under the curve of the individual sonographic scores ranged from 0.85 (the lowest) for subplacental hypervascularity to 0.91 for placental location in the lower uterine segment, myometrial thinning, and placental lacunae and 0.95 for the loss of clear zone. Only 4 studies included placental bulging in their sonographic score system, and therefore no meta-analysis for this score was performed. The integrated summary of the areas under the curve was 0.83 (95% confidence interval, 79-0.86). Forest plot analysis revealed integrated sensitivities and specificities of 0.68 (95% confidence interval, 0.53-0.80) and 0.88 (95% confidence interval, 0.68-0.96), respectively.

CONCLUSION

Clinical-sonographic score systems can contribute to the prenatal screening of patients at risk of placenta accreta spectrum at birth. Although we included multiple sonographic studies conducted during the mid-pregnancy period, standardized evaluation should be performed not only with strict ultrasound criteria for the placental position, mid third trimester gestational age at examination, and sonographic markers associated with PAS. Numeric sensitivities, specificities, NPVs, PPV, LR-, and LR+ should be recorded prospectively to assess their accuracy in different set-ups and PTP should be verified at delivery. The variables recommended for most predictive screening are: loss of clear zone underneath the placental bed, placentation in the LUS, and placenta lacunae.

Differentiating placenta accreta spectrum from scar dehiscence with underlying, non-adherent placenta: A systematic review of scoring systems and primary data analysis

INTRODUCTION

Accurate discrimination between placenta accreta spectrum (PAS) and scar dehiscence with underlying non-adherent placenta is challenging both on prenatal ultrasound and intraoperatively. This can lead to overdiagnosis of PAS and unnecessarily aggressive management of scar dehiscence which increases the risk of morbidity. Several scoring systems have been published which combine clinical and ultrasound information to help diagnose PAS in women at high risk. This research aims to provide insights into the reliability and utility of existing accreta scoring systems in differentiating these two closely related but different conditions to contribute to improved clinical decision making and patient outcomes.

MATERIAL AND METHODS

A literature search was performed in four electronic databases. The references of relevant articles were also assessed. The articles were then evaluated according to the predefined inclusion criteria. Primary data for testing each scoring system were obtained retrospectively from two hospitals with specialized PAS services. Each scoring system was used to evaluate the predicted outcome of each case.

RESULTS

The literature review yielded 15 articles. Of these, eight did not have a clearly described diagnostic criteria for accreta, hence were excluded. Of the remaining seven studies, one was excluded due to unorthodox diagnostic criteria and two were excluded as they differed from the other systems hindering comparison. Four scoring systems were therefore tested with the primary data. All the scoring systems demonstrated higher scores for high-grade PAS compared to scar dehiscence (p < 0.001) with an excellent Area Under the receiver operator characteristic Curve ranging from 0.82 (95% CI 0.71-0.92) to 0.87 (95% CI 0.79-0.96) in differentiating between these two conditions. However, no statistically significant differences were noted between the low-grade PAS and scar dehiscence on all scoring systems.

CONCLUSIONS

Most published scoring systems have no clearly defined diagnostic criteria. Scoring systems can differentiate between scar dehiscence with underlying non-adherent placenta from high-grade PAS with excellent diagnostic accuracy, but not for low-grade PAS. Hence, relying solely on these scoring systems may lead to errors in estimating the risk or extent of the condition which hinders preoperative planning.

Magnetic Resonance Imaging-Based Radiomics Nomogram to Predict Intraoperative Hemorrhage of Placenta Previa

OBJECTIVE

Placenta previa (PP) is associated with intraoperative and postpartum hemorrhage, increased maternal morbidity and mortality. We aimed to develop a magnetic resonance imaging (MRI)-based nomogram to preoperative prediction of intraoperative hemorrhage (IPH) for PP.

STUDY DESIGN

A total of 125 PP pregnant women were divided into a training set (n = 80) and a validation set (n = 45). An MRI-based model was built for the classification of patients into IPH and non-IPH groups in a training set and a validation set. Multivariate nomograms were built according to radiomics features. Receiver operating characteristic (ROC) curve was used to assess the model. Predictive accuracy of nomogram were assessed by calibration plots and decision curve analysis.

RESULTS

In multivariate analysis, placenta position, placenta thickness, cervical blood sinus, and placental signals in the cervix were significantly independent predictors for IPH (all ps < 0.05). The MRI-based nomogram showed favorable discrimination between IPH and non-IPH groups. The calibration curve showed good agreement between the estimated and the actual probability of IPH. Decision curve analysis also showed a high clinical benefit across a wide range of probability thresholds. Area under the ROC curve was 0.918 (95% confidence interval [CI]: 0.857-0.979) in the training set and 0.866 (95% CI: 0.748-0.985) in the validation set by the combination of four MRI features.

CONCLUSION

The MRI-based nomograms might be a useful tool for the preoperative prediction of IPH outcomes for PP. Our study enables obstetricians to perform adequate preoperative evaluation to reduce blood loss and cesarean hysterectomy.

KEY POINTS

· MRI is an important method for preoperative assessment of the risk of placenta previa.. · MRI-based nomogram can assess the risk of intraoperative bleeding of placenta previa.. · MRI is helpful for more comprehensive evaluation of placenta previa and adequate preoperative preparation..

Value of early pregnancy ultrasound combined with ultrasound score in the evaluation of placenta accreta in scar uterus: A retrospective cohort study

The objective of this study is to investigate the value of early pregnancy ultrasound combined with ultrasound score (USS) for the evaluation of placenta accreta (PA) in scar uteri. Thirty cases of PA in scar uteri diagnosed by ultrasound at our hospital between June 2021 and June 2022 were selected retrospectively (observation group). In addition, 30 patients had placenta attached to the anterior wall of the uterus and covered the internal orifice of the cervix; however, no PA was selected in the same period (control group). The results of surgical pathology and ultrasound examination in the first trimester of pregnancy (11-14 weeks of pregnancy, fetal top hip length 4.5-8.4 cm) were analyzed. Ultrasonic image characteristics of the 2 groups were scored using an ultrasonic scoring scale. The ultrasonic signs and ultrasonic scores of the 2 groups were analyzed. The diagnostic value of ultrasound and USS for PA in the scarred uterus alone and in combination was analyzed based on the gold standard of surgical and pathological results. The rich blood flow signal at the junction of the uterine serosa and bladder, the rate of blood flow in the cavity of the placental parenchyma, the thinning rate of the myometrium after placenta, and the abnormal rate of the low echo area after placenta in the observation group were significantly higher than those in the control group (P < .05). The USS of the observation group was significantly higher than that of the control group (P < .05). The sensitivity (93.33%) and accuracy (95.00%) of the combined examinations were significantly higher than those of ultrasound (70.00% and 83.33%, respectively) (P < .05). The sensitivity and accuracy of combined examination were slightly higher than those of USS examination (83.33% and 90.00%), but the difference was not statistically significant (P > .05). There was no significant difference between the specificity of combined examination (93.33%) and ultrasound (96.67%) and USS (96.67%) (P > .05). Early pregnancy ultrasound and USS evaluation have high application value in the diagnosis and evaluation of early scar uterine PA. The combination of the 2 methods can further improve the sensitivity and accuracy of diagnosis.

Deep Learning Model Based on Multisequence MRI Images for Assessing Adverse Pregnancy Outcome in Placenta Accreta

BACKGROUND

Preoperative assessment of adverse outcomes risk in placenta accreta spectrum (PAS) disorders is of high clinical relevance for perioperative management and prognosis.

PURPOSE

To investigate the association of preoperative MRI multisequence images and adverse pregnancy outcomes by establishing a deep learning model in patients with PAS.

STUDY TYPE

Retrospective.

POPULATION

323 pregnant women (age from 20 to 46, the median age is 33), suspected of PAS, underwent MRI to assess the PAS, divided into the training (N = 227) and validation datasets (N = 96).

FIELD STRENGTH/SEQUENCE

1.5T scanner/fast imaging employing steady-state acquisition sequence and single shot fast spin echo sequence.

ASSESSMENT

Different deep learning models (i.e., with single MRI input sequence/two sequences/multisequence) were compared to assess the risk of adverse pregnancy outcomes, which defined as intraoperative bleeding ≥1500 mL and/or hysterectomy. Net reclassification improvement (NRI) was used for quantitative comparison of assessing adverse pregnancy outcome between different models.

STATISTICAL TESTS

The AUC, sensitivity, specificity, and accuracy were used for evaluation. The Shapiro-Wilk test and t-test were used. A P value of <0.05 was considered statistically significant.

RESULTS

215 cases were invasive placenta accreta (67.44% of them with adverse outcomes) and 108 cases were non-invasive placenta accreta (9.25% of them with adverse outcomes). The model with four sequences assessed adverse pregnancy outcomes with AUC of 0.8792 (95% CI, 0.8645-0.8939), with ACC of 85.93% (95%, 84.43%-87.43%), with SEN of 86.24% (95% CI, 82.46%-90.02%), and with SPC of 85.62% (95%, 82.00%-89.23%) on the test cohort. The performance of model with four sequences improved above 0.10 comparing with that of model with two sequences and above 0.20 comparing with that of model with single sequence in terms of NRI.

DATA CONCLUSION

The proposed model showed good diagnostic performance for assessing adverse pregnancy outcomes.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Ultrasound scoring system for prenatal diagnosis of placenta accreta spectrum

BACKGROUND

To develop an ultrasound scoring system for placenta accreta spectrum (PAS), evaluate its diagnostic value, and provide a practical approach to prenatal diagnosis of PAS.

METHODS

A total of 532 pregnant women (n = 184 no PAS, n = 120 placenta accreta, n = 189 placenta increta, n = 39 placenta percreta) at high-risk for placenta accreta who delivered in the Third Affiliated Hospital of Zhengzhou University between January 2021 and December 2022 underwent prenatal ultrasound to evaluate placental invasion. An ultrasound scoring system that included placental and cervical morphology and history of cesarean section was created. Each feature was assigned a score of 0 ~ 2, according to severity. Thresholds for the total ultrasound score that discriminated between no PAS, placenta accreta, placenta increta, and placenta percreta were calculated.

RESULTS

Univariate and multivariate regression analysis identified seven indicators of PAS that were included in the ultrasound scoring system, including placental location, placental thickness, presence/absence of the retroplacental space, thickness of the retroplacental myometrium, presence/absence of placental lacunae, retroplacental myometrial blood flow and history of cesarean section. Using the final ultrasound scoring system, no PAS is diagnosed at a total score < 5, placenta accreta or placenta increta is diagnosed at a total score 5-10, and placenta percreta is diagnosed at a total score ≥ 10.

CONCLUSIONS

This study identified seven indicators of PAS and included them in an ultrasound scoring system that has good diagnostic efficacy and clinical utility.

TRIAL REGISTRATION

ChiCTR2300069261 (retrospectively registered on 10/03/2023).

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.

Comparison between placenta accreta scoring system, ultrasound staging, and clinical classification

Placenta accreta spectrum (PAS) is a series of disorders, which means that the placental trophoblast invades into the myometrium of the uterine wall. It is a serious obstetric complication which could be detected by ultrasound prenatally. In order to compare our placenta accreta scoring system with prenatal ultrasound staging system and International Federation of Gynecology and Obstetrics (FIGO) clinical classification, we did a retrospective study including 105 patients diagnosed with PAS disorders by operation or pathology at Peking University First Hospital, Beijing, China, between January, 2019 and December, 2020. Placenta accreta scoring system, prenatal ultrasound staging system and FIGO clinical classification were used on each patient. Basic information and clinical outcomes including gestational weeks, intraoperative hemorrhage, hysterectomy rate and blood transfusion were also counted. Both of placenta accreta scoring system, prenatal ultrasound staging system can give a rather clear prediction of placenta percreta, with their area under curve were 0.872 (95% confidential interval [CI]: 0.793-0.951) and 0.864 (95%CI: 0.779-0.949), P value were .000 compared with clinical classification. Beside for ultrasound staging system was designed for placenta previa patients, all those 3 criteria showed their relationships with preterm birth, hysterectomy rate and intraoperative bleeding. PAS scoring system also had the ability to predict a gestational week of delivery ≤34 weeks, intraoperative massive bleeding ≥2000 mL and hysterectomy at over 12 points. Our placenta accreta scoring system had good accordance with pre-operational ultrasound staging and FIGO clinical classification, with higher universality for patients without placenta previa.

Association between cervical length and massive intraoperative bleeding in patients with suspected placenta accreta spectrum combined with placenta previa: A retrospective cohort study

Purpose

Abnormal placentation is a spectrum disorder that includes creta, increta, and percreta; the term placenta accreta spectrum (PAS) disorders is used as a broad term to describe all of these conditions. PAS can lead to life-threatening hemorrhage. The predictive value of cervical length (CL) in patients with PAS remains controversial. Thus, this study investigated the relationship between CL and the probability of major bleeding in patients with PAS and placenta previa.

Methods

This retrospective cohort study was conducted at a comprehensive tertiary hospital in Chongqing, China, between January 2018 and December 2020. The target independent and dependent variables were CL and intraoperative massive bleeding, respectively. The covariates included demographic, clinical, and ultrasound characteristics. Logistic regression was used to explore the association between CL and massive bleeding.

Results

In total, 317 participants were enrolled, in whom the prevalence of massive bleeding was 41.9% (133/317). The threshold of CL associated with massive bleeding (≥1,000 ml) was 33 mm based on a receiver operating characteristic curve. In the fully adjusted model for each additional unit of CL, the risk of massive bleeding decreased by 7% [95% confidence interval (CI), 0.88–0.98]. The risk of major bleeding was reduced by 44% in patients with a CL greater than 33 mm (95% CI, 0.33–0.97) compared with patients with a CL less than 33 mm.

Conclusions

CL was negatively associated with massive intraoperative bleeding in patients with PAS combined with placenta previa. When the CL was greater than 33 mm, the risk of bleeding decreased by 44%. Thus, CL can be used as a standalone parameter to identify the risk of massive intraoperative bleeding in patients with suspected PAS.

Two-dimensional ultrasound signs as predictive markers of massive peri-operative blood loss in placenta previa suspicious for placenta accreta spectrum (PAS) disorder

OBJECTIVE

To evaluate certain two-dimensional (2D) ultrasound signs as predictors of massive peri-operative blood loss (PBL) in pregnant women with placenta previa suspicious of PAS disorder.

MATERIALS AND METHODS

A single center retrospective study was done in pregnant women who had undergone prenatal diagnosis with 2D ultrasound grey scale and color Doppler using the EW-AIP (which has been changed to IS-PAS (International Society for the Placenta Accreta Spectrum)) criteria between January 2007 and May 2021. The patients were divided into 2 groups, non-massive hemorrhage with PBL ≤ 2500 mL and massive PBL >2500 mL. All PAS cases had pathological confirmation. Ultrasound signs and hemorrhagic outcomes were compared between the two groups. A PAS scoring system to predict massive PBL was constructed and a receiver operating characteristic (ROC) curve was calculated to evaluate the efficacy of the scoring system.

RESULTS

Of 534 women, 146 (28.3%) had PBL > 2500 mL and 388 (71.7%) had PBL ≤ 2500 mL. In the massive PBL group, 101 (69.2%) were diagnosed as PAS and 45 (30.8%) as placenta previa alone. From 10 evaluated 2D ultrasound signs, 3 had the highest odds ratios (ORs) associated with massive PBL, 'focal exophytic mass' OR 8.17 (p = 0.024), 'placental bulge' OR 2.47 (p = 0.011), and 'placental lacunae feeder vessels' OR 2.38 (p = 0.01). When using the PAS scoring system, the AUC to predict massive PBL was 0.80 (95% CI, 0.76-0.85,).

CONCLUSION

Our PAS scoring system based on 2-dimensional ultrasound signs combined with grey scale and color Doppler is useful to predict massive PBL and can help optimize pre-operative management in cases of previa suspicious of PAS.

Association of the placenta accreta spectrum score and estimated blood loss in placenta accreta spectrum patients with placenta previa: a retrospective cohort study

PURPOSE

The placenta accreta spectrum (PAS) score calculated by the scoring system may predict patients with PAS. We aim to find the relationship between estimated blood loss and the PAS score. Further, find the inflection point, identify PAS patients with placenta previa who were at risk for major bleeding.

METHODS

The PAS patients with placenta previa, as diagnosed by color Doppler ultrasound, were divided into two groups according to their PAS scores using a new scoring system. Blood loss, transfusion requirements, the rate of Intra-Abdominal Balloon Occlusion (IABO), and other indicators were analyzed between groups.

RESULTS

The estimated blood loss, intraoperative transfusion, postoperative transfusion, operation time, and hospitalization time significantly increased in the group with a PAS score ≥ 9 (P < 0.05). The inflection point analysis revealed that a significant increase in estimated blood loss occurred when the PAS score was beyond 10 (crude) or 6 (adjusted for age, body mass index, and IABO).

CONCLUSION

There was a non-linear relationship between estimated intraoperative blood loss and PAS score. When the PAS score was greater than 9, hemorrhage, the risk of major bleeding, the need for transfusions, and the placement of an abdominal aortic balloon all increase significantly.

Ultrasound-based nomogram for postpartum hemorrhage prediction in pernicious placenta previa

Background: Pernicious placenta previa (PPP) is one of the most dangerous complications in pregnancy after cesarean section, with high perinatal mortality. This study aimed to develop a nomogram to predict postpartum hemorrhage in patients with PPP.

Methods: A total of 246 patients with confirmed PPP at Shengjing Hospital of China Medical University from January 2018 to December 2021 were included. Patients were divided into to two cohorts depending on a postpartum blood loss of > 1000 ml (n = 146) or ≤ 1000 ml (n = 100). Lasso regression analysis was performed on the risk factors screened by univariate analysis to screen out the final risk factors affecting postpartum hemorrhage. Based on the final risk factors, a Nomogram prediction model with excellent performance was constructed using Logistic regression. A nomogram was constructed with further screening of the selected risk factors of postpartum hemorrhage in PPP. A second nomogram based only on the total ultrasonic risk score was constructed. Decision curve analysis (DCA) was used to evaluate the clinical efficacy of the nomograms.

Results: Older age, larger gestational age, larger neonatal birth weight, presence of gestational diabetes mellitus, larger amniotic fluid index, absence of gestational bleeding, and higher ultrasonic risk single score were selected to establish a nomogram for postpartum hemorrhage in PPP. The area under the curve of the nomogram constructed by Lasso regression analysis was higher than that of the ultrasonic total score alone (0.887 vs. 0.833). Additionally, DCA indicated better clinical efficacy in the former nomogram than in the later nomogram. Furthermore, internal verification of the nomogram constructed by Lasso regression analysis showed good agreement between predicted and actual values.

Conclusion: A nomogram for postpartum hemorrhage in PPP was developed and validated to assist clinicians in evaluating postpartum hemorrhage. This nomogram was more accurate than using the ultrasonic score alone.

Developing and Validating Nomogram to Predict Severe Postpartum Hemorrhage in Women With Placenta Previa Undergoing Cesarean Delivery: A Multicenter Retrospective Case-Control Study

Objective

Developing and validating nomogram to predict severe postpartum hemorrhage (SPPH) in women with placenta previa (PP) undergoing cesarean delivery.

Methods

We conducted a multicenter retrospective case-control study in five hospitals. In this study, 865 patients from January, 2018 to June, 2020 were enrolled in the development cohort, and 307 patients from July, 2020 to June, 2021 were enrolled in the validation cohort. Independent risk factors for SPPH were obtained by using the multivariate logistic regression, and preoperative nomogram and intraoperative nomogram were developed, respectively. We compared the discrimination, calibration, and net benefit of the two nomograms in the development cohort and validation cohort. Then, we tested whether the intraoperative nomogram could be used before operation.

Results

There were 204 patients (23.58%) in development cohort and 80 patients (26.06%) in validation cohort experienced SPPH. In development cohort, the areas under the receiver operating characteristic (ROC) curve (AUC) of the preoperative nomogram and intraoperative nomogram were 0.831 (95% CI, 0.804, 0.855) and 0.880 (95% CI, 0.854, 0.905), respectively. In validation cohort, the AUC of the preoperative nomogram and intraoperative nomogram were 0.825 (95% CI, 0.772, 0.877) and 0.853 (95% CI, 0.808, 0.898), respectively. In the validation cohort, the AUC was 0.839 (95% CI, 0.789, 0.888) when the intraoperative nomogram was used before operation.

Conclusion

We developed the preoperative nomogram and intraoperative nomogram to predict the risk of SPPH in women with PP undergoing cesarean delivery. By comparing the discrimination, calibration, and net benefit of the two nomograms in the development cohort and validation cohort, we think that the intraoperative nomogram performed better. Moreover, application of the intraoperative nomogram before operation can still achieve good prediction effect, which can be improved if the severity of placenta accreta spectrum (PAS) can be accurately distinguished preoperatively. We expect to conduct further prospective external validation studies on the intraoperative nomogram to evaluate its application value.

Analysis of risk factors for massive intraoperative bleeding in patients with placenta accreta spectrum

BACKGROUND

To analyze relevant factors for massive postpartum hemorrhage in women with placenta accreta spectrum in order to improve the ability to identify those at risk for intraoperative bleeding and improve outcome.

METHODS

This study is a retrospective study and based on data from Hospital electronic medical record. Placenta accreta patients who delivered by cesarean section at Peking University Third Hospital from September 2017 to December 2019 were selected and included. According to the amount of intraoperative bleeding, they were categoried into the massive bleeding group (bleeding volume ≥ 2000 mL, 68 cases) and non-massive bleeding group (bleeding volume < 2000 mL, 99 cases). Univariate analysis and multivariate logistic regression were used to analyze the correlations between related risk factors or ultrasound imaging characteristics and the severity of bleeding during operation.

RESULTS

(1) There were statistically significant differences in gravidity, parity, number of prior cesarean deliveries and placenta accreta ultrasound scores (P < 0.05) between the two groups of patients. (2) Among the ultrasonographic indicators, the disappearance of the post-placental clear space, the emergence of cross-border blood vessels in the region of subplacental vascularity, interruption or disappearance of the bladder line, and the presence of the cervical blood sinus had the most significant correlation with hemorrhage during PAS (P < 0.05).

CONCLUSION

The presence of cervical blood sinus, interruption or disappearance of bladder line, the disappearance of the post-placental clear space and abnormal subplacental vascularity are independent risk factors for massive hemorrhage during PAS. We should pay more attention to these indicators in prenatal ultrasound examination in order to reduce the intraoperative bleeding and improve maternal outcomes.

Comparison between a prenatal sonographic scoring system and a clinical grading at delivery for Placenta Accreta Spectrum disorders

OBJECTIVE

Placenta Accreta Spectrum (PAS) disorders have become a major iatrogenic obstetric complication worldwide. Data on the accuracy of ultrasound examination diagnosis are limited by incomplete confirmation and variability in the description of the different grades of PAS at delivery. The aim of this study was to compare our prenatal routine sonographic screening and diagnostic scoring system with a standardized clinical grading system at birth in patient at risk of PAS.

STUDY DESIGN

This is a retrospective cohort study of 607 pregnant patients with at least one prior cesarean delivery between December 2013 and December 2018. All patients were assessed for PAS using our institutional prenatal sonographic scoring system and the corresponding ultrasound findings were compared with those of a standardized clinical intra-operative macroscopic grading system of the degree of accreta placentation at vaginal birth or laparotomy.

RESULTS

PAS was diagnosed clinically at birth in 50 (8.2%) cases, 17 of which were confirmed by histopathology. A low (score ≤ 5), medium (score 6-7), high (score ≥ 8) probability for PAS was reported in 502, 61 and 44 cases, respectively. The probability score increased significantly (p < .001) in women ≥2 prior cesarean deliveries, with an anterior low-lying/placenta previa, with absent clear space, increased in retroplacental vascularity and with the size and numbers of lacunae. The number of cases classified clinically as grade 1 (non-PAS) and 3 (adherent PAS) was significantly (p < .001) lower in women with a high probability score whereas the rates of the other grades was significantly (p < .001) higher. The widest discrepancy between ultrasound probability score and clinical grade was found for grade 2 which, describes a partial placental adherence and grades 4 and 5 which, refer to placental percreta which describes tissue having invade trough the uterine serosa and beyond.

CONCLUSIONS

Both ends of the spectrum of accreta placentation remain difficult to diagnose antenatal and clinically at birth, in particular when no histopathologic confirmation is available. There is a need to develop ultrasound accuracy score systems that can differentiate between the different grades of PAS and which are validated by standardized clinical and pathology protocols.

Ultrasound detection rates of the placenta accreta spectrum with prior myomectomy

OBJECTIVE

To describe the performance of ultrasound in detecting placenta accreta spectrum (PAS) in patients with history of prior myomectomy.

METHODS

A retrospective cohort study of patients who were referred for sonographic evaluation of the placenta and delivered at a tertiary academic center from 2012 to 2019. Demographic, obstetric, sonographic findings, and pathology information were collected and analyzed using Chi-square, t-tests, and ANOVA analysis.

RESULTS

640 patients met inclusion criteria, including 46 (7.2%) with histologically confirmed PAS. Groups for comparison included those with C-section only (CS), CS-Myomectomy, and Myomectomy-only. Those with CS-Myomectomy were older (38.7 years vs. 35.7 years or 35.5 years, p = .003) and those with CS only were more likely to have an anterior placenta (63.4% vs. 54.5% or 41.8%, p = .005). The rate of PAS was highest in those with Myomectomy only (14.5% vs. 6.1% or 11.4%, p = 0.04). Sensitivity, Specificity, and Predictive Values were lowest in the CS-Myomectomy group, with detection rate and PPV of only 40%. Accuracy, defined as the rate of clinical outcome consistent with imaging, was significantly higher in those with CS only compared to the CS with myomectomy or myomectomy-only groups. Of the histologically confirmed PAS, 11 (23.9%) did not have a placenta previa, and the majority of these occurred in women with prior myomectomy. In the cohort with CS only, the proportion of cases with PAS without placenta previa was 5 of 33 (15.2%) compared to 6 of 13 (46.2%) of PAS in those with prior myomectomy, with or without CS (p = .05).

CONCLUSION

In patients with prior uterine surgery referred for sonographic evaluation of the placenta, rates of histology-confirmed PAS were highest in those with prior myomectomy, though ultrasound accuracy was lower in these patients. As ultrasound findings of PAS may be clearer in the presence of placenta previa, the absence of previa in a higher proportion of PAS with prior myomectomy may be related to the observed lower sonographic accuracy in these patients.

Analysis of clinical features of 231 cases with pernicious placenta previa: A retrospective cohort study

Pernicious placenta previa (PEPP) is a severe complication of late pregnancy, which might result in adverse maternal-fetal outcome. To explore the application value of placenta accreta score (PAS) for PEPP and its association with maternal-fetal outcome.In this retrospective cohort study, the clinical data of PEPP patients were analyzed. According to the ultrasonic PAS, patients were grouped into 3 groups: scores ≤5, a scores between 6 and 9, and scores ≥10. The clinical data, intraoperative and postoperative outcomes were collected. Receiver operating characteristic (ROC) curves were used to evaluate the performance of PAS in disease severity evaluation. Multivariate logistic and linear regression analysis were performed to assess associations of PAS with intraoperative and postoperative outcomes.A total of 231 patients were enrolled. There were significant differences in intraoperative, postoperative and neonatal outcomes, such as operation time, bladder repair, ICU admission, postoperative hospitalization days, operation complications, Apgar score of newborns in 1 minute and premature delivery among the 3 groups (all P < .05), while the worst outcomes were found in those with a score ≥ 10 (all P < .05). According to ROC curves, scores <5.5, between 5.5 and 7.5, and >7.5 indicated placenta accreta, placenta increta and placenta percreta, respectively. PAS was independently associated with longer time of operation, surgical complications, intraoperative bleeding volume, and postoperative hospitalization days (all P < .05).Placenta accreta score might help with PEPP subtype diagnosis and predict the maternal-fetal outcome of PEPP patients.

Ultrasonographic Diagnosis of Placenta Accreta Spectrum (PAS) Disorder: Ideation of an Ultrasonographic Score and Correlation with Surgical and Neonatal Outcomes

The objective of this study was to evaluate a novel ultrasonographic scoring system for the diagnosis of PAS and the prediction of maternal and neonatal outcomes. In this retrospective study, 138 patients with at least one previous caesarean section (CS) and placenta previa were included. They were divided into four groups ranging from Group 0 (Non PAS) to Group 3 (Placenta Percreta) according to the histological or surgical confirmation. Their ultrasound examinations during pregnancy were reviewed according to the nine different ultrasound signs reported by the European Working Group on Abnormally Invasive Placenta. For each parameter, 0 to 2 points were assigned. The sum of the points reflects the severity of PAS with a maximum score of 20. The scoring system revealed good performances in evaluation metrics, with an overall accuracy of 94%. In addition to this, patients’ characteristics and surgical and neonatal outcomes were analyzed with an evidence of higher incidence of complications in severe forms. Our study suggests that antenatal ultrasonographic diagnosis of PAS is feasible with sufficient level of accuracy. This will be important in identifying high-risk patients and implementing preventive strategy.

The role of ultrasound in prediction of intra-operative blood loss in cases of placenta accreta spectrum disorders

PURPOSE

To assess the value of various grey-scale ultrasound, 2D color Doppler, and 3D power Doppler sonographic markers in predicting major intraoperative blood loss during planned cesarean hysterectomy for cases diagnosed with placenta accreta spectrum (PAS) disorders.

METHODS

50 women diagnosed with PAS were scanned the day before planned delivery and hysterectomy for various sonographic markers indicative of placental invasion. These women were then later divided according to blood loss in two groups: group A (minor hemorrhage, < 2500 ml), and group B (major hemorrhage, > 2500 ml), and the data were analyzed.

RESULTS

The odds ratio (OR) for major hemorrhage was as follows for the following sonographic markers: 'number of lacunae > 4' OR 3.8 95% CI (1.0-13.8) (p = 0.047); 'subplacental hypervascularity' OR 10.8 95% CI (1.2-98.0) (p = 0.035); 'tortuous vascularity with 'chaotic branching' OR 10.8 95%CI (1.2-98.0) (p = 0.035); 'numerous coherent vessels involving the serosa-bladder interface OR 14.6 95% CI (2.7-80.5) (p = 0.002); and 'presence of bridging vessels OR 2.9 95% CI (1.4-6.9) (p = 0.005). Only the presence of numerous coherent vessels involving the bladder-serosal interface (p = 0.002) was proven to be independent predictor of major hemorrhage during hysterectomy.

CONCLUSION

The use of 2D color Doppler and 3D power Doppler can help predict massive hemorrhage in cases of PAS disorders.

Comparison between abdominal ultrasound and nuclear magnetic resonance imaging detection of placenta accreta in the second and third trimester of pregnancy

This study is to determine accuracy of abdominal ultrasound and nuclear magnetic resonance imaging (MRI) for placenta accreta in the second and third trimester of pregnancy and to define the most relevant features of abdominal ultrasound and MRI for placenta accreta prediction.Between September 2012 and September 2018, 245 high risk of placenta accreta in the second trimester of pregnancy were prenatal diagnosed by abdominal ultrasound and MRI and they were followed up until the end of pregnancy.Forty-six patients at the second trimester of pregnancy and 40 patients at the third trimester of pregnancy were confirmed as placenta accreta. For the second and third trimester of pregnancy, the sensitivity (Se), specificity (Sp), positive and negative predictive value (PPV and NPV) of abdominal ultrasound were 95.65% versus 97.50%, 91.78% versus 90.70%, 88% versus 83%, and 97% versus 99%, respectively, while the Se, Sp, PPV, and NPV of MRI were 89.13% versus 92.50%, 87.67% versus 8721%, 82% versus 77%, and 93% versus 96%, respectively. Five features having significant statistical differences between normal placentation women and placenta accreta patients in second or third trimester of pregnancy, including loss of the normal retroplacental clear space, thinning or disappearance of the myometrium, increased vascularization at the uterine serosa-bladder wall interface, and vascularization perpendicular to the uterine wall on abdominal ultrasound, and uterine bulging and dark intraplacental bands on MRI.Abdominal ultrasound and MRI for placenta accreta in the second and third trimester of pregnancy could provide meaningful imaging evidences.

The parameters affecting the success of uterus-sparing surgery in cases of placenta adhesion spectrum disorder

OBJECTIVE

This study aimed to evaluate the parameters affecting the treatment success of conservative surgery in cases with placental invasion anomaly.

METHODS

Archive files and digital image records of 67 patients with placental invasion anomaly were studied. The patients were divided into two groups, a conservative surgery group and a cesarean hysterectomy group. Demographic data, cervical length, placental localization, placental surface area adhering to previous cesarean section line, preoperative and postoperative hematocrit values, transfused blood products, and surgical complications were compared between the two groups.

RESULTS

In the conservative surgery group, the cervical length was longer (p < .001) and the surface area of the placenta in the previous cesarean scar line was smaller (p < .001). For cervical length, the sensitivity and specificity values were 97 and 81%, respectively, when the cut-off value was 35.5 mm. When the cut-off value for the placental surface area in the previous cesarean scar line was 85.5 cm², the sensitivity and specificity values were 68 and 72%, respectively. In the caesarean hysterectomy group, the preoperative and postoperative hematocrit values were lower (p < .001, p = .003, respectively), and the amount of transfused erythrocyte suspension and fresh frozen plasma were higher (p < .001, p = .001, respectively).

CONCLUSION

In this study, it was concluded that the presence of the nondestructive intact cervical tissue, in the cases with placental invasion anomaly and/or the small size of the placental surface area adhering to the previous cesarean scar line, increase the feasibility of conservative surgery.