The prenatal diagnostic indicators of placenta accreta spectrum disorders

Machine learning applications in placenta accreta spectrum disorders

This review examines the emerging applications of machine learning (ML) and radiomics in the diagnosis and prediction of placenta accreta spectrum (PAS) disorders, addressing a significant challenge in obstetric care. It highlights recent advancements in ML algorithms and radiomic techniques that utilize medical imaging modalities like magnetic resonance imaging (MRI) and ultrasound for effective classification and risk stratification of PAS. The review discusses the efficacy of various deep learning models, such as nnU-Net and DenseNet-PAS, which have demonstrated superior performance over traditional diagnostic methods through high AUC scores. Furthermore, it underscores the importance of integrating quantitative imaging features with clinical data to enhance diagnostic accuracy and optimize surgical planning. The potential of ML to predict surgical morbidity by analyzing demographic and obstetric factors is also explored. Emphasizing the need for standardized methodologies to ensure consistent feature extraction and model performance, this review advocates for the integration of radiomics and ML into clinical workflows, aiming to improve patient outcomes and foster a multidisciplinary approach in high-risk pregnancies. Future research should focus on larger datasets and validation of biomarkers to refine predictive models in obstetric care.

Advances in Prenatal Diagnosis of Placenta Accreta Spectrum

Placenta accreta spectrum (PAS) involves abnormal placental attachment and can lead to severe complications such as postpartum hemorrhage and hysterectomy. Ultrasound is the main tool used to screen for PAS due to its non-invasive nature and convenience, although its accuracy depends on the skill of the operator. Magnetic Resonance Imaging has emerged as a supplementary tool, especially for complex cases or posterior placentas, providing more accurate anatomical detail and enabling the invasion depth and location to be assessed. This review summarizes recent advances in prenatal imaging for PAS, aiming to improve diagnostic accuracy and guide future research.

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

OBJECTIVE

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.

METHODS

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).

RESULTS

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.

CONCLUSION

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.

Additional Role of Magnetic Resonance Imaging to Ultrasound in Assessing Placenta Accreta Spectrum Disorders: A Retrospective Cross-sectional Study from Vietnam

Objectives

Placenta accreta spectrum (PAS) is commonly associated with adverse pregnancy outcomes. While ultrasound (US) is the primary imaging tool, magnetic resonance imaging (MRI) plays a crucial complementary role in assessing PAS disorders. This study aimed to evaluate the MRI features in PAS diagnosis and enhance the role of MRI in conjunction with US for better management. Additionally, the study examined the association between imaging findings and clinical outcomes.

Methods

This retrospective cross-sectional study was conducted between January 2017 and June 2022 at Tu Du Hospital, Vietnam. A total of 87 cases were eligible for inclusion. Antenatal MRI and US findings were compared to intraoperative diagnoses and/or histopathological confirmation, which is considered the gold standard. The diagnostic value of each MRI feature was calculated, and the association between MRI/US findings, estimated blood loss, and surgical methods was analyzed. Statistical significance was determined with a p-value < 0.05.

Results

Among the 87 women suspected of PAS on US, 83 were confirmed to have PAS through intraoperative diagnosis and/or histology. The mean maternal age was 35.9 5.7 years and the mean gestational age at cesarean section was 31.1 7.1 weeks. MRI sensitivity (Se) in detecting PAS ranged from 10.8-94.0%, while the specificity (Sp) ranged from 25.0-100%. Loss of retroplacental T2 dark zone demonstrated the highest diagnostic value. When combining three to six MRI signs, Se increased from 53.0-100%, and Sp from 25.0-100%. The highest Youden?(tm)s index (0.759) was observed with five MRI signs (Se = 75.9%, Sp = 100%). PAS diagnosed via MRI/US was associated with more significant blood loss during cesarean section (1000 (600-2000) mL vs. 500 (250-850) mL and 1000 (600-2000) mL vs. 300 (300-500) mL, respectively). Furthermore, the percreta type of PAS identified on MRI/US was linked to significantly higher rates of cesarean hysterectomy compared to conservative surgery (56.4% vs. 43.6% and 63.5% vs. 36.5%, respectively).

Conclusions

MRI provides a reliable diagnostic value for PAS, particularly following uncertain US findings. Depending on resource availability, a stepwise approach utilizing both imaging modalities should be considered. MRI can guide strict interdisciplinary management in cases of suspected PAS, especially percreta type. Further studies are needed to solidify the role of MRI in severe PAS cases.

MR Imaging of Placenta Accreta Spectrum: A Comprehensive Literature Review of the Most Recent Advancements

This article delves into the latest MR imaging developments dedicated to diagnosing placenta accreta spectrum (PAS). PAS, characterized by abnormal placental adherence to the uterine wall, is of paramount concern owing to its association with maternal morbidity and mortality, particularly in high-risk pregnancies featuring placenta previa and prior cesarean sections. Although ultrasound (US) remains the primary screening modality, limitations have prompted heightened emphasis on MR imaging. This review underscores the utility of quantitative MR imaging, especially where US findings prove inconclusive or when maternal body habitus poses challenges, acknowledging, however, that interpreting placenta MR imaging demands specialized training for radiologists.

Diagnostic Role of Cell-Free miRNAs in Identifying Placenta Accreta Spectrum during First-Trimester Screening

Placenta accreta spectrum (PAS) is a severe complication of pregnancy associated with excessive invasion of cytotrophoblast cells at the sites of the endometrial-myometrial interface and the myometrium itself in cases of adherent (creta) and invasive (increta and percreta) forms, respectively. This leads to a high risk of massive blood loss, maternal hysterectomy, and preterm birth. Despite advancements in ultrasound protocols and found associations of alpha-fetoprotein, PAPP-A, hCG, PLGF, sFlt-1, IL-8, and IL-33 peripheral blood levels with PAS, there is a high need for an additional non-invasive test to improve the diagnostic accuracy and to select the real PAS from the suspected ones in the first-trimester screening. miRNA signatures of placental tissue, myometrium, and blood plasma from women with PAS in the third trimester of pregnancy, as well as miRNA profiles in exosomes from the blood serum of women in the first trimester with physiologically progressing pregnancy, complicated by PAS or pre-eclampsia, were obtained using deep sequencing. Two logistic regression models were constructed, both featuring statistically significant parameters related to the levels of miR-26a-5p, miR-17-5p, and miR-101-3p, quantified by real-time PCR in native blood serum. These models demonstrated 100% sensitivity in detecting PAS during the first pregnancy screening. These miRNAs were identified as specific markers for PAS, showing significant differences in their blood serum levels during the first trimester in the PAS group compared to those in physiological pregnancies, early- or late-onset pre-eclampsia groups. Furthermore, these miRNAs exhibited differential expression in the PAS placenta and/or myometrium in the third trimester and, according to data from the literature, control angiogenesis. Significant correlations were found between extracellular hsa-miR-101-3p and nuchal translucency thickness, hsa-miR-17-5p and uterine artery pulsatility index, and hsa-miR-26a-5p and hsa-miR-17-5p with PLGF. The developed test system for early non-invasive PAS diagnosis based on the blood serum level of extracellular miR-26a-5p, miR-17-5p, and miR-101-3p can serve as an auxiliary method for first-trimester screening of pregnant women, subject to validation with independent test samples.

Meta-analysis for the relationship between circulating pregnancy-associated plasma protein A and placenta accreta spectrum

BACKGROUND

Changes in circulating pregnancy-associated plasma protein A (PAPP-A) have been observed in women with a placenta accreta spectrum (PAS). However, no consensus has been reached according to the previous studies. Our study investigated the relationship between circulating PAPP-A and PAS risk through a systematic review and meta-analysis.

METHODS

Studies comparing the circulating level of PAPP-A between pregnant women with and without PAS were obtained by searching the Medline, Cochrane Library, Embase, CNKI, and Wanfang databases from the inception of the databases until February 12, 2023. Heterogeneity was considered in the pooling of results via a random-effects model.

RESULTS

Eight observational studies were obtained for the meta-analysis, which included 243 pregnant women with PAS and 1599 pregnant women without PAS. For all these women, the first-trimester circulating level of PAPP-A was measured by immunoassay and reported as multiples of the median (MoM) values. The pooled results showed that compared to those who did not develop PAS, women with PAS had significantly higher first-trimester serum level PAPP-A (mean difference: 0.43 MoM, 95% confidence interval [CI]: 0.30 to 0.56, P < .001; I2 = 32%). Furthermore, a high first-trimester serum PAPP-A level was related to a high PAS risk (odds ratio: 2.89, 95% CI: 2.13 to 3.92, P < .001; I2 = 0%). Sensitivity analysis which excluded one study at a time, also obtained similar results (p all < 0.05).

CONCLUSION

Pregnant women with a high serum PAPP-A level in the first trimester may be at an increased risk for PAS.