Clinical factors associated with a placenta accreta spectrum

Clinical outcomes and future fertility after uterine artery embolization for postpartum and post-abortion hemorrhage

BACKGROUND

Postpartum hemorrhage (PPH) and post-abortion hemorrhage (PAH) are life-threatening conditions.

PURPOSE

To evaluate the efficacy and safety of uterine arterial embolization (UAE) for PPH and PAH and to investigate future fertility after UAE.

MATERIAL AND METHODS

This study included 57 consecutive patients (mean age = 34 years) who underwent UAE for PPH (n = 46) and PAH (n = 11) at our institution between January 2011 and December 2022. Technical success, non-visualization of the peripheral portion of bilateral uterine arteries on angiography, and clinical success, complete hemostasis after UAE, were assessed. UAE-associated complications and factors related to clinical success were analyzed. Pregnancy outcomes after UAE and complications during subsequent pregnancy were investigated in 16 patients who desired fertility and were followed up for >1 year.

RESULTS

The technical and clinical success rates were 100% and 84.2%, respectively. Sepsis (n = 1) and uterine empyema (n = 1) were observed as severe complications. Placental disorder, bleeding within 24 h after delivery or abortion, ≥1.5 shock index, ≥6 units of transfusion erythrocytes, and ≥8 obstetrical disseminated intravascular coagulation score were significantly associated with unfavorable clinical outcomes. In total, 16 pregnancies were observed in 12 patients after UAE, three of which were miscarriages and 13 were successful live births. During pregnancy, uterine rupture (n = 1) and accreta (n = 1) were observed.

CONCLUSION

UAE is an effective treatment for PPH and PAH. Although UAE could preserve future fertility, careful attention should be paid to perinatal management for unusual complications.

Risk factors for placenta accreta spectrum without prior cesarean section: A case-control study in China

OBJECTIVE

To identify the risk factors for placenta accreta spectrum (PAS) disorders in women without prior cesarean section (CS).

METHODS

This retrospective case-control study investigated patients without prior CS who gave birth at Peking University Third Hospital between January 1, 2015 and December 31, 2021. Patients diagnosed with PAS according to the clinical diagnostic criteria of the 2019 International Federation of Gynecology and Obstetrics (FIGO) classification were included as the study group. Patients were matched as the control group according to delivery date and placenta previa, in a 1:2 allocation ratio. Maternal characteristics were compared between the two groups.

RESULTS

The study included 348 patients in the study group and 696 in the control group. The multivariate analysis showed that the independent risk factors of PAS consisted of operative hysteroscopy (once: adjusted odds ratio [aOR] 2.38, 95% CI 1.28-4.24, P = 0.006; twice or more: aOR 5.43, 95% CI 1.04-28.32, P = 0.045), uterine curettage (once: aOR 2.54, 95% CI 1.80-3.58, P < 0.001; twice: aOR 3.01, 95% CI 1.81-5.02, P < 0.001; three or more times: aOR 9.18, 95% CI 4.64-18.18, P < 0.001), multifetal pregnancy (aOR 5.64, 95% CI 3.01-10.57, P < 0.001), adenomyosis (aOR 2.77, 95% CI 1.23-6.22, P = 0.014), in vitro fertilization (aOR 1.51, 95% CI 1.04-2.20, P = 0.030) and pre-eclampsia (aOR 2.72, 95% CI 1.36-5.45, P = 0.005), and the independent protective factor was being multiparous (aOR 0.37, 95% CI 0.25-0.54, P < 0.001).

CONCLUSION

After controlling the effect of placenta previa, we found that patients with PAS without prior CS had unique maternal characteristics. Classification and quantification of the intrauterine surgeries they have undergone is essential for identifying high-risk patients. Early identification of high-risk groups by risk factors has the potential to improve the prognosis considerably.

Clinical Risk Factors for Placenta Accreta or Placenta Percreta: A Case-Control Study

OBJECTIVES

Uterine scarring is a risk factor for placenta accreta spectrum (PAS) disorder. We aimed to determine the factors related to PAS in women who had previously undergone a cesarean.

METHODS

We performed a case-control study where women who underwent postpartum hysterectomy for placenta accreta/percreta (cases) were matched to all women with a previous cesarean who delivered in the week before each case (controls). Maternal characteristics along with previous cesarean characteristics were compared between cases and controls. Univariate and multivariate logistic regression analyses were performed to determine risk factors related to PAS.

RESULTS

We compared 64 cases of PAS that required hysterectomy to 192 controls. The factors related to PAS were a history of uterine surgery (OR 27.4; 95% CI 5.1-146.5, P < 0.001) and the number of previous cesareans (2 cesareans: OR 7.2; 95% CI 3.4-15.4, P < 0.001; more than 2 cesareans: OR 7.9; 95% CI 2.9-21.5, P < 0.001). In women with a single previous cesarean without previous uterine surgery, an interdelivery interval of fewer than 18 months (OR 6.3; 95% CI 1.8-22.4, P = 0.004) and smoking (OR 5.8; 95% CI 1.2-27.8, P = 0.03) were related to PAS. The gestational age and the cervical dilatation at previous cesarean were not associated with PAS (all with P > 0.05). The lack of data regarding the closure of the uterus at previous cesareans prevents us from drawing solid conclusions.

CONCLUSIONS

Previous uterine surgery, the number of previous cesareans, smoking, and an interdelivery interval of fewer than 18 months after cesarean are significant risk factors for PAS requiring postpartum hysterectomy.

Sonographic Findings of Vascular Signals for Retained Products of Conception in Women Following First-Trimester Termination of Pregnancy

OBJECTIVES

To evaluate the occurrence of retained products of conception (RPOC) after termination of pregnancy in the first trimester and to assess the vascular signals with transvaginal ultrasonography (TVUS) examination in the detection of retained products.

METHODS

A retrospective cohort study was performed using TVUS examination in patients following termination of pregnancy. In cases of RPOC, 3 scales of vascular signal were identified: type 1, no or small amount, spot flow signals; type 2, medium amount, strip-like flow signals; type 3, rich amount, circumferential-like flow signals. The correlation between vascular signals and placenta accreta spectrum (PAS) staging was proposed by sonography and histopathology findings.

RESULTS

The 3 vascular patterns were differently distributed within non-RPOC as well as RPOC patients with and without PAS: type 1 vascular signal detection rates of non-RPOC and RPOC were 97.8% (262/268) and 28.1% (18/64), respectively. Of 64 cases of RPOC, 48.4% (31/64) of the patients had type 2 vascular signals. Vascular signals were enhanced in RPOC with PAS patients whose diagnosis was confirmed by histopathology.

CONCLUSIONS

The vascularity (amount of flow), vascular pattern (spot, strip- or circumferential-like flow), and the flow penetrating myometrium were significant findings for distinguishing concomitant RPOC with and without PAS. Additionally, RPOC may contribute to PAS progression, or PAS and RPOC in coordination strengthen the observed vascular signals.

Does repetitive dilatation and curettage or hysteroscopic biopsy in patients treated with progestins for endometrial hyperplasia or carcinoma affect subsequent fetomaternal outcomes? A population-based study using the National Health Insurance Research Database of Taiwan

OBJECTIVE

To investigate the impact of repeated dilatation and curettage or hysteroscopic biopsy on fetomaternal outcomes in patients receiving progestin treatment for endometrial hyperplasia or early-stage carcinoma.

METHOD

This was a population-based study using the Taiwan National Health Insurance Research Database between 2009 and 2017 of women who gave birth and had a history of endometrial hyperplasia and early-stage carcinoma treated with progestins. Logistic regression analysis was used to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs) reflecting the association between repeated procedures and fetomaternal outcomes.

RESULTS

A total of 6956 women with 8690 deliveries were identified. Compared with those who had two or fewer procedures, women who received more than two procedures had a significantly higher risk for cervical insufficiency (aOR, 5.09 [95 CI, 2.31-11.24]). Furthermore, women who had more than two procedures were prone to have adverse neonatal outcomes, including Apgar score < 7 at 1 min (aOR, 1.97 [95% CI, 1.13-3.43]) and 5 min (aOR, 3.11 [95% CI, 1.33-7.23]) and preterm delivery <32 weeks (aOR, 2.86 [95% CI, 1.50-5.45]).

CONCLUSION

Undergoing more than two procedures was associated with subsequent maternal cervical insufficiency, preterm delivery <32 weeks, and low neonatal Apgar score. Health care providers should be aware of the potential risks and balance the benefits and harms of repeated procedures.

Segmentation methods applied to MRI-derived radiomic analysis for the prediction of placenta accreta spectrum in patients with placenta previa

PURPOSE

To retrospectively evaluate the performance of different manual segmentation methods of placenta MR images for predicting Placenta Accreta Spectrum (PAS) disorders in patients with placenta previa (PP) using a Machine Learning (ML) Radiomics analysis.

METHODS

64 patients (n=41 with PAS and n= 23 without PAS) with PP who underwent MRI examination for suspicion of PAS were retrospectively selected. All MRI examinations were acquired on a 1.5 T using T2-weighted (T2w) sequences on axial, sagittal and coronal planes. Ten different manual segmentation methods were performed on sagittal placental T2-weighted images obtaining five sets of 2D regions of interest (ROIs) and five sets of 3D volumes of interest (VOIs) from each patient. In detail, ROIs and VOIs were positioned on the following areas: placental tissue, retroplacental myometrium, cervix, placenta with underneath myometrium, placenta with underneath myometrium and cervix. For feature stability testing, the same process was repeated on 30 randomly selected placental MRI examinations by two additional radiologists, working independently and blinded to the original segmentation. Radiomic features were extracted from all available ROIs and VOIs. 100 iterations of 5-fold cross-validation with nested feature selection, based on recursive feature elimination, were subsequently run on each ROI/VOI to identify the best-performing method to classify instances correctly.

RESULTS

Among the segmentation methods, the best performance in predicting PAS was obtained by the VOIs covering the retroplacental myometrium (Mean validation score: 0.761, standard deviation: 0.116).

CONCLUSION

Our preliminary results show that the VOI including the retroplacental myometrium using T2w images seems to be the best method when segmenting images for the development of ML radiomics predictive models to identify PAS in patients with PP.

Animal models of the placenta accreta spectrum: current status and further perspectives

Placenta accreta spectrum disorder (PAS) is a kind of disease of placentation defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium, even penetrating the uterus. Decidual deficiency, abnormal vascular remodeling in the maternal-fetal interface, and excessive invasion by extravillous trophoblast (EVT) cells contribute to its onset. However, the mechanisms and signaling pathways underlying such phenotypes are not fully understood, partly due to the lack of suitable experimental animal models. Appropriate animal models will facilitate the comprehensive and systematic elucidation of the pathogenesis of PAS. Due to the remarkably similar functional placental villous units and hemochorial placentation to humans, the current animal models of PAS are based on mice. There are various mouse models induced by uterine surgery to simulate different phenotypes of PAS, such as excessive invasion of EVT or immune disturbance at the maternal-fetal interface, which could define the pathological mechanism of PAS from the perspective of the "soil." Additionally, genetically modified mouse models could be used to study PAS, which is helpful to exploring the pathogenesis of PAS from the perspectives of both "soil" and "seed," respectively. This review details early placental development in mice, with a focus on the approaches of PAS modeling. Additionally, the strengths, limitations and the applicability of each strategy and further perspectives are summarized to provide the theoretical foundation for researchers to select appropriate animal models for various research purposes. This will help better determine the pathogenesis of PAS and even promote possible therapy.

The role of internal iliac artery intraoperative vascular clamp temporary occlusion in abnormally invasive placenta

OBJECTIVE

To investigate the efficacy of internal iliac artery intraoperative vascular clamp temporary occlusion in the treatment of abnormally invasive placenta.

METHOD

This retrospective study enrolled 153 patients diagnosed with abnormally invasive placenta between January 2018 and December 2021. The patients were divided into a study group (n = 88, undergoing cesarean section followed by internal iliac artery vascular clamp temporary occlusion) and a control group (n = 65, receiving routine cesarean section). The general situation, intraoperative conditions, postoperative complications, and neonatal outcomes were compared between the two groups.

RESULTS

The hysterectomy rate in the study group was significantly lower than that in the control group. However, there were no significant differences in intraoperative blood loss, blood transfusion, postoperative intensive care unit transfer rate, or neonatal outcome between the groups. Further subgrouping showed that in patients with placenta increta, the hysterectomy rate and intraoperative bleeding amount were significantly lower in the occlusion group. Nevertheless, these advantages were not significantly different between the groups in patients with placenta percreta.

CONCLUSION

Vascular clamp temporary occlusion of internal iliac artery is an effective method for controlling hemorrhage and decreasing the incidence of hysterectomy in patients with placenta increta. For patients with placenta percreta, the benefit is limited.

Prediction of placenta accreta spectrum by combining deep learning and radiomics using T2WI: a multicenter study

PURPOSE

To achieve prenatal prediction of placenta accreta spectrum (PAS) by combining clinical model, radiomics model, and deep learning model using T2-weighted images (T2WI), and to objectively evaluate the performance of the prediction through multicenter validation.

METHODS

A total of 407 pregnant women from two centers undergoing preoperative magnetic resonance imaging (MRI) were retrospectively recruited. The patients from institution I were divided into a training cohort (n = 298) and a validation cohort (n = 75), while patients from institution II served as the external test cohort (n = 34). In this study, we built a clinical prediction model using patient clinical data, a radiomics model based on selected key features, and a deep learning model by mining deep semantic features. Based on this, we developed a combined model by ensembling the prediction results of the three models mentioned above to achieve prenatal prediction of PAS. The performance of these predictive models was evaluated with respect to discrimination, calibration, and clinical usefulness.

RESULTS

The combined model achieved AUCs of 0.872 (95% confidence interval, 0.843 to 0.908) in the validation cohort and 0.857 (0.808 to 0.894) in the external test cohort, both of which outperformed the other models. The calibration curves demonstrated excellent consistency in the validation cohort and the external test cohort, and the decision curves indicated high clinical usefulness.

CONCLUSION

By using preoperative clinical information and MRI images, the combined model can accurately predict PAS by ensembling clinical model, radiomics model, and deep learning model.

Association of Placenta Previa With Severe Maternal Morbidity Among Patients With Placenta Accreta Spectrum Disorder

IMPORTANCE

Placenta previa is widely acknowledged as a risk factor for placenta accreta spectrum (PAS) disorders, which are severe maternal complications; however, data are limited regarding whether placenta previa is associated with a higher risk of worse maternal outcomes among patients with PAS disorders.

OBJECTIVE

To examine the association between placenta previa and the risk of severe maternal morbidities (SMMs) and higher resource use among patients with PAS disorders.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study extracted records of 3793 patients with PAS diagnosis and delivery indicators between October 1, 2015, and December 31, 2019, from the US National Inpatient Sample database.

EXPOSURES

Placenta previa.

MAIN OUTCOMES AND MEASURES

Data on 21 Centers for Disease Control and Prevention-defined SMMs and 25 study-defined surgical morbidities associated with PAS were extracted. Six surgical procedures (cystoscopy, intra-arterial balloon occlusion, cesarean delivery, hysterectomy, cystectomy, and oophorectomy), hospital length of stay, and inpatient costs were compared. Multivariable Poisson regression models built in the generalized estimating equation framework were used.

RESULTS

Among 3793 patients with PAS (median [IQR] age at admission, 33 [29-37] years), 621 women (16.4%) were Black, 765 (20.2%) were Hispanic, 1779 (46.9%) were White, 441 (11.6%) were of other races and/or ethnicities (47 [1.2%] were American Indian, 220 [5.8%] were Asian or Pacific Islander, and 174 [4.6%] were of multiple or other races and/or ethnicities), and 187 (4.9%) were of unknown race and ethnicity. A total of 1323 patients (34.9%) had placenta previa and 2470 patients (65.1%) did not; of those with placenta previa, 405 patients (30.6%) had invasive PAS. Patients with vs without placenta previa had a significantly higher rate and risk of any SMM (935 women [70.7%] vs 1087 women [44.0%]; P < .001; adjusted risk ratio [aRR], 1.19; 95% CI, 1.12-1.27) and any surgical morbidity (1170 women [88.4%] vs 1667 women [67.5%]; P < .001; aRR, 1.18; 95% CI, 1.13-1.23). With regard to specific outcomes, those with vs without placenta previa had a significantly higher rate of peripartum hemorrhage (878 patients [66.4%] vs 1217 patients [49.3%]; P < .001), blood product transfusion (413 patients [31.2%] vs 610 patients [24.7%]; P < .001), shock (83 patients [6.3%] vs 108 patients [4.4%]; P = .01), disseminated intravascular coagulation or other coagulopathy (77 patients [5.8%] vs 105 patients [4.3%]; P = .04), and urinary tract injury (44 patients [3.3%] vs 41 patients [1.7%]; P = .002). Patients with vs without placenta previa were more likely to undergo cesarean delivery (1292 patients [97.7%] vs 1787 patients [72.3%]; P < .001), hysterectomy (786 patients [59.4%] vs 689 patients [27.9%]; P < .001), cystoscopy (301 patients [22.8%] vs 203 patients [8.2%]; P < .001), cystectomy (157 patients [11.9%] vs 98 patients [4.0%]; P < .001), and intra-arterial balloon occlusion (121 patients [9.1%] vs 77 patients [3.1%]; P < .001) and to have significantly longer hospital length of stay (median [IQR], 5 [4-11] days vs 3 [3-5] days; P < .001) and total inpatient costs (median [IQR], $17 496 [$10 863-$30 619] vs $9728 [$6130-$16 790]; P < .001). Hypertensive disorder of pregnancy was associated with a decreased risk of placenta previa (aRR, 0.67; 95% CI, 0.46-0.96) among patients with PAS.

CONCLUSIONS AND RELEVANCE

In this study, placenta previa was associated with an increased risk of maternal and surgical morbidities and higher resource use among women with PAS. These findings suggest that interventions to alleviate maternal and surgical morbidities are especially needed for patients with placenta previa-complicated PAS disorders.