Placenta accreta spectrum: pathophysiology and evidence-based anatomy for prenatal ultrasound imaging

Scoring system for the prediction of the severity of placenta accrete spectrum in women with placenta previa: a prospective observational study

PURPOSE

The clinical outcomes are significantly different in accreta, increta, and percreta. There is currently no scoring system that can preoperatively distinguish its severity in an at-risk population. The aim of this study is to establish a scoring system for the prediction of the severity of placenta accrete spectrum (PAS) in women with placenta previa.

METHODS

A prospective observational study was conducted in patients with placenta previa who delivered at a Chinese tertiary care center between June 12, 2016 and June 30, 2018. Optimal scaling regression was performed to determine the parameters which really contribute to the prediction of PAS, and calculate percentage of contribution.

RESULTS

Among 392 cases with placenta previa, 79, 53, and 28 had been surgically and/or histologically confirmed as accreta, increta, or percreta, respectively. Seven parameters were scheduled for the estimated scores for PAS, and five of them were finally entered into the predictive model. Their percentage of contribution was as follows: placental lacunas (19%), vascularity at the uterus-bladder interface (17.5%), myometrial thickness and hypoechoic retroplacental zone (25.6%), bladder line (22.6%), and previous caesarean sections (15.3%). The thresholds of scores for the prediction of accreta, increta, and percreta yielded 2.25-6.2, 6.2-8.95, and ≧ 8.95, respectively, with the positive and negative predictive value, and false positive rates of the scoring system were 96.68%, 95.44%, and 3.32%, respectively.

CONCLUSIONS

The scoring system can predict the severity of PAS in women with placenta previa. This will help identify the actual high-risk patients and improve their treatment.

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.

Evidence-based guidelines for the management of abnormally invasive placenta: recommendations from the International Society for Abnormally Invasive Placenta

The worldwide incidence of abnormally invasive placenta is rapidly rising, following the trend of increasing cesarean delivery. It is a heterogeneous condition and has a high maternal morbidity and mortality rate, presenting specific intrapartum challenges. Its rarity makes developing individual expertise difficult for the majority of clinicians. The International Society for Abnormally Invasive Placenta aims to improve clinicians' understanding and skills in managing this difficult condition. By pooling knowledge, experience, and expertise gained within a variety of different healthcare systems, the Society seeks to improve the outcomes for women with abnormally invasive placenta globally. The recommendations presented herewith were reached using a modified Delphi technique and are based on the best available evidence. The evidence base for each is presented using a formal grading system. The topics chosen address the most pertinent questions regarding intrapartum management of abnormally invasive placenta with respect to clinically relevant outcomes, including the following: definition of a center of excellence; requirement for antenatal hospitalization; antenatal optimization of hemoglobin; gestational age for delivery; antenatal corticosteroid administration; use of preoperative cystoscopy, ureteric stents, and prophylactic pelvic arterial balloon catheters; maternal position for surgery; type of skin incision; position of the uterine incision; use of interoperative ultrasound; prophylactic administration of oxytocin; optimal method for intraoperative diagnosis; use of expectant management; adjuvant therapies for expectant management; use of local surgical resection; type of hysterectomy; use of delayed hysterectomy; intraoperative measures to treat life-threatening hemorrhage; and fertility after conservative management.

Pathophysiology of Placenta Accreta Spectrum Disorders: A Review of Current Findings

Current findings continue to support the concept of a biologically defective decidua rather than a primarily abnormally invasive trophoblast. Prior cesarean sections increase the risk of placenta previa and both adherent and invasive placenta accreta, suggesting that the endometrial/decidual defect following the iatrogenic creation of a uterine myometrium scar has an adverse effect on early implantation. Preferential attachment of the blastocyst to scar tissue facilitates abnormally deep invasion of trophoblastic cells and interactions with the radial and arcuate arteries. Subsequent high velocity maternal arterial inflow into the placenta creates large lacunae, destroying the normal cotyledonary arrangement of the villi.

Machine learning analysis of MRI-derived texture features to predict placenta accreta spectrum in patients with placenta previa

PURPOSE

To evaluate whether a machine learning (ML) analysis employing MRI-derived texture analysis (TA) features could be useful in assessing the presence of placenta accreta spectrum (PAS) in patients with placenta previa (PP). The hypothesis is that TA features may reflect histological abnormalities underlying PAS in patients with PP thus helping in differentiating positive from negative cases.

MATERIALS AND METHODS

Pre-operative MRI examinations of 64 patients with PP of which 20 positive (12 accreta, 7 increta and 1 percreta) and 44 negative for PAS were retrospectively selected. Multiple (n = 3) rounded regions of interest (ROIs) were manually positioned on sagittal or coronal T2-weighted images over homogeneous placental tissue close to the placental-myometrial interface for each patient to extract TA features. After balancing the dataset with the Synthetic Minority Over-sampling Technique, training and testing sets were obtained using Hold-out with a 75/25% split. Different algorithms were applied on the training set using the wrapper method, which looks for the best combination of features based on the optimization of a heuristic function in order to get the highest accuracy, and a 10-fold Cross-validation. The accuracy of the best models was also assessed on the test set. Histology was used as the standard of reference.

RESULTS

A total of 192 ROIs were positioned and a ROI-based analysis was then conducted. Among the different algorithms, k-nearest neighbors obtained the highest accuracy (98.1%), precision (98.7%), sensitivity (97.5%) and specificity (98.7%) while exploiting the lowest number of features (n = 26); conversely, the Naïve Bayes algorithm got the lowest scores showing an accuracy of 80.5%.

CONCLUSION

ML analysis using MRI-derived TA features could be a feasible tool in the identification of placental tissue abnormalities underlying PAS in patients with PP. This approach might represent an additional tool in the clinical practice, thus expanding the application field of artificial intelligence to medical images.

Prenatal planning of placenta previa: diagnostic accuracy of a novel MRI-based prediction model for placenta accreta spectrum (PAS) and clinical outcome

PURPOSE

To investigate the diagnostic accuracy of MRI for placenta accreta spectrum (PAS) and clinical outcome prediction in women with placenta previa, using a novel MRI-based predictive model.

METHODS

Thirty-eight placental MRI exams performed on a 1.5T scanner were retrospectively reviewed by two radiologists in consensus. The presence of T2 dark bands, myometrial thinning, abnormal vascularity, uterine bulging, placental heterogeneity, placental protrusion sign, placental recess, and percretism signs was scored using a 5-point scale. Pathology and clinical intrapartum findings were the standard of reference for PAS, while intrapartum/peripartum bleeding and emergency hysterectomy defined the clinical outcome. Receiver-operating characteristic (ROC) analysis and discriminant function analysis were performed to test the predictive power of MRI findings for both PAS and clinical outcome prediction.

RESULTS

Abnormal vascularity and percretism signs were the two most predictive MRI features of PAS. The area under the curve (AUC) of the predictive function was 0.833 (cutoff 0.39, 67% sensitivity, 100% specificity, p = 0.001). Percretism signs and myometrial thinning were the two most predictive MRI features of poor outcome. AUC of the predictive function was 0.971 (cutoff - 0.55, 100% sensitivity, 77% specificity, p < 0.001).

CONCLUSION

The diagnostic accuracy of MRI, especially considering the combination of the most predictive MRI findings, is higher when the target of the prediction is the clinical outcome rather than the PAS.

Maternal and neonatal outcomes following a proactive peripartum multidisciplinary management protocol for placenta creta spectrum as compared to the urgent delivery

BACKGROUND

Adherent and invasive placenta, termed Placenta Creta Spectrum (PCS), is associated with increased maternal morbidity and mortality. Incidence and risk factors for Placenta Creta are on the rise and call to optimize the obstetric care for this condition.

OBJECTIVES

We sought to compare maternal and neonatal outcomes between a ProActive Peripartum Multidisciplinary Approach (PAMA) as compared to the urgent management of the Placenta Creta Spectrum patients.

STUDY DESIGN

We conducted a single-center prospective observational study between 2005-2016. PCS patients registered with the implementation of a PAMA protocol 2014-2016 epoch(E2) were compared with the pre-PAMA 2005-2013 epoch(E1), managed by urgent team recruitment. The PAMA protocol is grounded on a continuum of care; A. Antenatal: PCS risk assessment based on clinical history and imaging, surgical, anesthesia, urological consults and designation of a dedicated team to be present at planned surgery; B. Delivery: planned at 34-35 weeks, massive transfusion protocol activation, insertion of ureteral catheters, vertical uterine incision, placement of vessel loops on the iliac vessels, avoidance of active placenta delivery, followed by the decision of hysterectomy or uterine repair; C. Post-operative care: intensive care admission. We evaluated maternal and neonatal outcomes.

RESULTS

During the study period 158,438 deliveries were registered in our institution; we identified a total of 72 PCS cases (0.05%): 50(69.4%) in E1 and 22 (30.6%) in E2. Patient characteristics were comparable among epochs. Significantly, patients in E2 vs. E1 had fewer events of massive blood transfusion 36.0% vs. 13.6%, p = 0.05; were transfused less RBC units: median 4 vs. 1.5, p = 0.012, had no transfusion-related respiratory complications and hemorrhage control re-laparotomies. Hysterectomy and hollow visceral injury rates were comparable (72% vs. 63.7%, 26% vs. 22%; respectively). The hysterectomy pathology assessment was available for the majority of the cases in both epochs; percreta diagnosis rate significantly increased in E2. The neonatal outcome was similar among the epochs.

CONCLUSIONS

Institution of a PAMA protocol for PCS resulted in eliminating the urgent deliveries and in reducing the associated significant hemorrhagic related maternal morbidity, with no increase in the rate of hysterectomy or adverse neonatal outcome.

Maternal short-term complications after planned cesarean delivery without medical indication: A registry-based study

INTRODUCTION

The aim of this study was to compare short-term maternal outcomes in healthy primiparous women with uncomplicated pregnancies who delivered a singleton child at term by planned cesarean or planned vaginal delivery.

MATERIAL AND METHODS

Nationwide population-based cohort study of 145 821 low-risk primiparous women with healthy singletons in cephalic position in Denmark, 2008-2016. Data from the Medical Birth Register and the Danish National Patient Registry were linked and compared according to planned mode of delivery. Main outcome measures were major morbidity including maternal death, cardiac arrest, hysterectomy and thromboembolic disease. Minor maternal morbidity includes wound infection, postpartum fever, wound rupture and reoperation, bladder lesions, spinal headache and Ogilvie syndrome. Additionally, anal sphincter injuries were registered.

RESULTS

The study included 141 782 planned vaginal deliveries and 4039 planned cesarean deliveries. Severe maternal complications occurred in fewer than 1/4000 in both categories. Women with planned cesarean had a slightly higher risk of wound infections (0.17% vs 0.07%; P = 0.04). There were no significant differences in the remaining minor and major outcomes. Women with planned vaginal delivery had a 4.97% risk of obstetric anal sphincter injuries.

CONCLUSIONS

For healthy primiparous women, both planned vaginal delivery and planned cesarean delivery are highly safe procedures when the short-term maternal outcome is taken into account. Planned cesarean delivery is associated with a slightly increased risk of wound infection compared with planned vaginal delivery. Women with planned vaginal delivery had a 4.97% risk of obstetric anal sphincter injuries.

Conservative treatment for well-differentiated endometrial cancer: when and why it should be considered in young women

The aim of this review was to update current knowledge on the conservative treatment of endometrial cancer (EC) based on a literature review. A web-based search in the MEDLINE database was carried out on EC management and treatment. All relevant information has been collected and analysed. Case series were mainly found in the literature search. Conservative treatments were offered to young patients with stage I low-grade endometrioid carcinomas of the endometrium. Different options included high/low dose progestin treatments, hysteroscopic resection of the disease, a levonorgestrel intrauterine device or a combination of various strategies. The overall complete response rate was near 76.5% with a recurrence rate of up to 33.8%. Pregnancy outcomes reached rates of 64.8% for live births. The current clinical outcomes show that conservative treatment aimed at preserving fertility is feasible for stage I endometrial well-differentiated adenocarcinomas in motivated patients under close monitoring.

Two approaches for placenta accreta spectrum: B-lynch suture versus pelvic artery endovascular balloon

Purpose: Management of patients with placenta accreta spectrum (PAS) varies widely, and scarce data exist concerning its management. The current study compared two different surgical approaches in the management of PAS: the B-lynch approach (Group A) compared to the endovascular balloon catheters (Group B)Methods: A retrospective cohort study in two tertiary university-affiliated hospitals between the years 2004 and 2015. Elective cesarean section was planned at 35-37 weeks of gestation. One center utilized the B-lynch approach and the second utilized the endovascular balloon catheter approach.Results: The cesarean hysterectomy rate was significantly higher in the Group A approach compared to Group B (36.1 versus 29.2%, p = .00). The number of packed cells units administered during and postoperatively were higher in the Group A compared with Group B (p = .006 and .043, respectively). Overall, surgery length and hospitalization duration were shorter in patients who underwent cesarean hysterectomy compared with those who underwent uterine preservation (B-lynch or endovascular balloon catheters) (p = .000 and p = .004, respectively).Conclusions: The endovascular balloon technique seems to be a better option for uterine preservation due to less blood loss and higher postoperative hemoglobin level. Nevertheless, for those women who have completed their family planning, cesarean hysterectomy with the placenta left in situ is the safer and more suitable option.

The role of supracervical hysterectomy in reducing blood products requirement in the management of placenta accreta: a case-control study

Objective: While surgical management is the treatment of choice for abnormally invasive placenta, the role of supracervical hysterectomy in this setting is not well established. We aimed to compare supracervical versus total cesarean hysterectomy as a surgical option for abnormally invasive placenta.Methods: We carried out an 8-year retrospective case-control study. Six cases of a patient treated by total hysterectomy were matched and compared to 30 controls treated by supracervical hysterectomy. Matching of cases with controls was based on coexisting placenta previa, a number of previous cesarean sections, and age, with five controls per case. Cases and controls were comparable in placental invasion topography. We compared the operative approach in all histologically identified cases of abnormally invasive placenta.Results: Overall, 36 women with histologically proven abnormally invasive placenta were identified. Composite blood products morbidity was higher among total hysterectomy patients (p = .02). Freshly frozen plasma utilization was greater among total hysterectomy patients (p = .01). Median operative time (142 ± 48 versus 136 ± 58 minutes) and hospitalization time (8.9 ± 3.1 versus 7.3 ± 1.5 days) were comparable between those who underwent supracervical versus total hysterectomy (p > .05). No case of maternal or neonatal death was encountered.Conclusion: The favorable maternal and perinatal outcomes observed in our study, suggest that supracervical hysterectomy should be considered as the first-line approach in cases of abnormally invasive placenta managed operatively.

MRI prognosticators for adverse maternal and neonatal clinical outcome in patients at high risk for placenta accreta spectrum (PAS) disorders

BACKGROUND

Placenta accreta spectrum (PAS) disorders may be associated with significant mortality and morbidity for both mother and fetus.

PURPOSE/HYPOTHESIS

To identify MRI risk factors for poor peripartum outcome in gravid patients at risk for PAS.

STUDY TYPE

Prospective.

POPULATION

One hundred gravid women (mean age: 34.9 years) at third trimester, with placenta previa.

FIELD STRENGTH/SEQUENCE

T₂ -SSTSE (single-shot turbo spin echo), T₂ -TSE, T₁ -TSEFS (TSE images with fat-suppression) at 1.5T.

ASSESSMENT

Fifteen MRI features considered indicative of PAS were recorded by three radiologists and were tested for any association with the following adverse peripartum maternal and neonatal events: increased operation time, profound blood loss, hysterectomy, bladder repair, ICU admission, prematurity, low birthweight, and 5-minute APGAR score <7.

STATISTICAL TESTS

Kappa (K) coefficients were computed as a measure of agreement between intraoperative information/histology and MRI results as well as for interobserver agreement; chi-square and Fisher's exact tests were used to explore the association of the MRI signs with clinical complications. A score was calculated by adding all recorded MRI signs and its predictive ability was tested using receiver operating characteristic (ROC) analysis, against all complications, separately; odds ratios (ORs) for optimal cutoffs were determined with logistic regression analysis.

RESULTS

There was excellent agreement (K >0.75, P < 0.001) between MRI and intraoperative findings for invasive placenta, bladder and parametrial involvement. Intraplacental T₂ dark bands, myometrial disruption, uterine bulge, and hypervascularity at the utero-placental interface or parametrium, showed significant association (P < 0.005) with poor clinical outcome for both mother and fetus. The MRI score showed significant predictive ability for each adverse maternal event (area under the curve [AUC]: 0.85-0.97, P < 0.001). The presence of ≥3 MRI signs was the cutoff point for a complicated delivery (OR: 19.08, 95% confidence interval [CI]: 6.05-60.13) and ≥6 MRI signs was the cutoff point for massive bleeding (OR: 90.93, 95% CI: 11.3-729.23), hysterectomy (OR: 72.5, 95% CI: 17.9-293.7), or extensive bladder repair (OR: 58.74, 95% CI: 7.35-469.32). The MRI score was not significant for predicting adverse neonatal events including preterm delivery (P = 0.558), low birthweight (P = 0.097), and 5-minute Apgar score (P = 0.078).

DATA CONCLUSION

Preoperative identification of specific MRI features may predict peripartum course in high-risk patients for PAS.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:602-618.

Placenta Accreta Spectrum

Placenta accreta spectrum, formerly known as morbidly adherent placenta, refers to the range of pathologic adherence of the placenta, including placenta increta, placenta percreta, and placenta accreta. The most favored hypothesis regarding the etiology of placenta accreta spectrum is that a defect of the endometrial-myometrial interface leads to a failure of normal decidualization in the area of a uterine scar, which allows abnormally deep placental anchoring villi and trophoblast infiltration. Maternal morbidity and mortality can occur because of severe and sometimes life-threatening hemorrhage, which often requires blood transfusion. Although ultrasound evaluation is important, the absence of ultrasound findings does not preclude a diagnosis of placenta accreta spectrum; thus, clinical risk factors remain equally important as predictors of placenta accreta spectrum by ultrasound findings. There are several risk factors for placenta accreta spectrum. The most common is a previous cesarean delivery, with the incidence of placenta accreta spectrum increasing with the number of prior cesarean deliveries. Antenatal diagnosis of placenta accreta spectrum is highly desirable because outcomes are optimized when delivery occurs at a level III or IV maternal care facility before the onset of labor or bleeding and with avoidance of placental disruption. The most generally accepted approach to placenta accreta spectrum is cesarean hysterectomy with the placenta left in situ after delivery of the fetus (attempts at placental removal are associated with significant risk of hemorrhage). Optimal management involves a standardized approach with a comprehensive multidisciplinary care team accustomed to management of placenta accreta spectrum. In addition, established infrastructure and strong nursing leadership accustomed to managing high-level postpartum hemorrhage should be in place, and access to a blood bank capable of employing massive transfusion protocols should help guide decisions about delivery location.

A prospective evaluation and management of different types of placenta praevia using parallel vertical compression suture to preserve uterus

The rising tendency of cesarean sections will lead invariably to more complications such as placenta praevia. The aim of our study was to evaluate the utility of parallel vertical compression suture to preserve uterus in cases of placenta praevia, and to propose a rational approach of these problematic cases, according to their grade of myometrial invasion.We prospectively included 95 consecutive cases diagnosed with placenta praevia (group1 [Gr1]) where we used parallel compression suture and compared to retrospectively analyzed 100 consecutive cases managed without using this technique (group 2 [Gr2]). We differentiated the types of placenta praevia according to their invasion in myometrium because this parameter appreciates best their degree of severity, so we had 4 Grs: simple praevia (no adherent), accreta, increta, and percreta. All patients underwent ultrasound evaluation before surgery. Cesarean section was planned at 35 to 36 weeks. The main goal was to preserve the uterus whenever was possible. After opening the peritoneal cavity, we first inspected the lower segment and bladder. If no signs of engorged and tortuous vessels we dissected first the bladder and then performed a transverse hysterotomy, removed the placenta and placed 2 parallel vertical sutures on the lower segment below the hysterotomy incision through the entire thickness of both uterine walls. In cases of massively engorged vessels we dissected the bladder after infant delivery and made a transverse uterine incision slightly higher. We measured the amount of blood loss and performed three postoperative ultrasound exams, on day 2, 4 and at 6 to 8 weeks.Using this technique, we were able to preserve the uterus in 98.33% of Gr1 versus 78.47% from Gr2 of simple placenta praevia, in 88.23% in Gr1 compared to 42.86% in Gr2 of placenta accreta, only in 14.28% of increta type and in none (0%) of the 2 cases with placenta percreta.The simplified compression technique for hemostasis and preserving uterus in cases of simple placenta praevia and accreta is easy to perform without special surgical skills and is rapid. There are no short and long-time complications related to the technique. In cases of placenta increta the problem is not that this technique is unsuccessful but getting to that point to place the sutures is difficult. In severe cases of placenta percreta, unfortunately, the hysterectomy remains the treatment of choice.

Retrospective analysis of 113 consecutive cases of placenta accreta spectrum from a single tertiary care center

Objective: Placenta accreta spectrum (PAS) remains a major cause of maternal morbidity. We sought to assess the characteristics and treatment outcomes of PAS managed at a tertiary care center with high volume of PAS.Study design: Electronic medical records of all patients with diagnosis of PAS from June 2010 to October 2016 were reviewed. Details of obstetric backgrounds, predelivery diagnosis, peripartum management, and outcomes were analyzed.Results: One hundred thirteen women with PAS were identified from 50,448 deliveries during the study period. Vaginal delivery, emergency, and elective cesarean section were accomplished in 41.6, 30.1, and 28.3%, respectively. There was no maternal mortality. Approximately 41.6% of women with PAS had peripartum hysterectomy. There was a fair inverse correlation between intraoperative blood loss and gestational weeks at delivery (r = -0.311; p=.001), but not gestational weeks at diagnosis (p = .249). Cases with predelivery diagnosis (n = 29) had higher intraoperative blood loss than those diagnosed postdelivery (n = 84) (p<.001). Anterior PAS (n = 58) is associated with attachment to previous uterine scar, antepartum bleeding, and intraoperative blood loss compared to posterior PAS (n = 44) (p<.05). The PAS patients with previous uterine surgery had the highest chance of peripartum hysterectomy (p<.001).Conclusions: Contradictory to previous reports, our data suggest a more severe spectrum of PAS in those with predelivery detection earlier gestational weeks at delivery. Peripartum hysterectomy was highest in anterior PAS that attached to the previous uterine scar.

Matsubara-Yano suture: a simple uterine compression suture for postpartum hemorrhage during cesarean section

AIMS

The aims of this study were to clarify: (i) the effectiveness of Matsubara-Yano uterine compression suture (MY) to achieve hemostasis in the presence of postpartum hemorrhage (PPH) during cesarean section, (ii) the type of PPH for which MY is effective, (iii) post-operative complications of MY, and (iv) outcomes of pregnancy after MY.

METHODS

This retrospective observational study was performed using medical records of patients for whom MY had been performed between January 1, 2009 and December 31, 2017.

RESULTS

MY was performed for 50 patients, with hemostasis achieved in 46 (92%). The other four (8%: 4/50) patients required transarterial embolization or hysterectomy. Of these four, three patients had placenta accreta spectrum (PAS) disorder-related bleeding. Post-operative complications were observed in three (6%: 3/50) patients, with all showing intrauterine infection. All three patients recovered solely with antibiotics. Eight pregnancies were confirmed (five livebirths, two spontaneous abortions in the first trimester, and one case of ongoing pregnancy). Of the five livebirths, one resulted in cesarean hysterectomy due to placenta previa with PAS disorders.

CONCLUSIONS

MY had a hemostatic effect on PPH. All cases except one with hemostatic failure were associated with PAS disorders, indicating that the hemostatic rate was lower in those with PAS than non-PAS disorders.

Influence of prenatal diagnosis of abnormally invasive placenta on maternal outcome: systematic review and meta-analysis

OBJECTIVE

To ascertain the impact of prenatal diagnosis on surgical outcome of women affected by abnormally invasive placenta (AIP).

METHODS

MEDLINE, EMBASE, CINAHL and Cochrane databases were searched. Observed outcomes included: gestational age at birth (weeks), amount of blood loss (L), units of red blood cells (RBC), platelets (PLT) and fresh frozen plasma (FFP) transfused, length of stay in hospital and the intensive care unit (ICU) (days), urinary tract injury and infection. Only studies reporting the occurrence of any of the explored outcomes in women with a prenatal compared with an intrapartum diagnosis of AIP were considered eligible for inclusion. Random-effect head-to-head meta-analyses were used to analyze the data.

RESULTS

Thirteen studies were included. Women with a prenatal diagnosis of AIP had less blood loss during surgery (mean difference (MD), -0.87; 95% CI, -1.5 to -0.23), had fewer units of RBC (MD, -1.45; 95% CI, -2.9 to -0.04) and FFP (MD, -1.73; 95% CI, -3.3 to -0.2) transfused, and delivered earlier (MD, 1.33 weeks; 95% CI, -2.23 to -0.43) compared with those with an intrapartum diagnosis. The risk of admission to an ICU and length of in-hospital and in-ICU stay were not different between the groups. Prenatal diagnosis of AIP was associated with a higher risk of urinary-tract injury (odds ratio, 2.5; 95% CI, 1.3-4.6), mainly due to the higher prevalence of placenta percreta in the group with AIP diagnosed prenatally.

CONCLUSION

Prenatal diagnosis of AIP is associated with reduced hemorrhagic morbidity compared with cases in which such anomalies are detected at delivery. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Automatic Lacunae Localization in Placental Ultrasound Images via Layer Aggregation

Accurate localization of structural abnormalities is a precursor for image-based prenatal assessment of adverse conditions. For clinical screening and diagnosis of abnormally invasive placenta (AIP), a life-threatening obstetric condition, qualitative and quantitative analysis of ultrasonic patterns correlated to placental lesions such as placental lacunae (PL) is challenging and time-consuming to perform even for experienced sonographers. There is a need for automated placental lesion localization that does not rely on expensive human annotations such as detailed manual segmentation of anatomical structures. In this paper, we investigate PL localization in 2D placental ultrasound images. First, we demonstrate the effectiveness of generating confidence maps from weak dot annotations in localizing PL as an alternative to expensive manual segmentation. Then we propose a layer aggregation structure based on iterative deep aggregation (IDA) for PL localization. Models with this structure were evaluated with 10-fold cross-validations on an AIP database (containing 3,440 images with 9,618 labelled PL from 23 AIP and 11 non-AIP participants). Experimental results demonstrate that the model with the proposed structure yielded the highest mean average precision (mAP=35.7%), surpassing all other baseline models (32.6%, 32.2%, 29.7%). We argue that features from shallower stages can contribute to PL localization more effectively using the proposed structure. To our knowledge, this is the first successful application of machine learning to placental lesion analysis and has the potential to be adapted for other clinical scenarios in breast, liver, and prostate cancer imaging.

'Nausicaa' compression suture: a simple and effective alternative to hysterectomy in placenta accreta spectrum and other causes of severe postpartum haemorrhage

Postpartum haemorrhage (PPH), especially resulting from placenta accreta spectrum (PAS), has become a worldwide concern in maternity care. We describe a novel method of uterine compression sutures (the ‘Nausicaa’ technique) as an alternative to hysterectomy for patients who have suffered from major PPH. We applied this technique in 68 patients with major PPH during caesarean section (including 43 patients with PAS, 20 patients with placenta praevia totalis, and five patients with uterine atony), and none of these patients required further hysterectomy. We conclude that our Nausicaa suture is a simple and feasible alternative to hysterectomy in patients suffering from major PPH.

Systematic review of prostaglandin analogues for retained placenta

BACKGROUND

Medical management of retained placenta could be a safe alternative to manual removal.

OBJECTIVE

To evaluate the efficacy of prostaglandin analogues for retained placenta.

SEARCH STRATEGY

MEDLINE, EMBASE, CENTRAL, ICTRP, LILACS, and OpenSIGLE were searched without language restrictions from inception to January 31, 2017, by combining terms for retained placenta and prostaglandin analogues.

SELECTION CRITERIA

Randomized controlled trials comparing prostaglandin analogues with any other intervention.

DATA COLLECTION AND ANALYSIS

Trials were independently assessed for inclusion, data extraction, and risk of bias. Data were extracted for meta-analyses. GRADE was used to evaluate the quality of data.

MAIN RESULTS

Seven randomized controlled trials (851 patients) were included. Prostaglandins did not increase the placenta expulsion rate (relative risk [RR] 1.40, 95% confidence interval [CI] 0.83-2.36) or decrease maternal transfusion (RR 0.72, 95% CI 0.43-1.22). In comparison with oxytocin, prostaglandins did not modify the expulsion rate (RR 1.26, 95% CI 0.90-1.78), maternal transfusion (RR 1.05, 95% CI 0.27-4.09), or time for delivery of placenta (mean difference -1.56 minutes, 95% CI, -9.25-6.13). Three trials comparing prostaglandins with oxytocin agonists, ergometrine, and manual removal reported similar results.

CONCLUSIONS

Prostaglandin analogues do not offer an effective alternative for management of retained placenta.

Placenta Accreta Spectrum: A Review of Pathology, Molecular Biology, and Biomarkers

Background. Placenta accreta spectrum (PAS) is a condition of abnormal placental invasion encompassing placenta accreta, increta, and percreta and is a major cause of severe maternal morbidity and mortality. The diagnosis of a PAS is made on the basis of histopathologic examination and characterised by an absence of decidua and chorionic villi are seen to directly adjacent to myometrial fibres. The underlying molecular biology of PAS is a complex process that requires further research; for ease, we have divided these processes into angiogenesis, proliferation, and inflammation/invasion. A number of diagnostic serum biomarkers have been investigated in PAS, including human chorionic gonadotropin (HCG), pregnancy-associated plasma protein-A (PAPP-A), and alpha-fetoprotein (AFP). They have shown variable reliability and variability of measurement depending on gestational age at sampling. At present, a sensitive serum biomarker for invasive placentation remains elusive. In summary, there are a limited number of studies that have contributed to our understanding of the molecular biology of PAS, and additional biomarkers are needed to aid diagnosis and disease stratification.

Abnormal placentation: Current evidence and review of the literature

Abnormal placentation often requires the involvement of a multidisciplinary team of medical caregivers. Practicing Obstetrics is a challenging and skillful duty. This is more obvious in cases of abnormal placentation, which represents one of the most dangerous and complex clinical conditions in materno-fetal medicine. Pathological placentation involves position and invasion abnormalities and represents a serious and potentially life-threatening condition for both the pregnant woman and the fetus. The dramatic increase in cesarean section rates is an important factor which could explain the rapid raise in abnormal placentation cases, which were considered rare a few years ago. Nevertheless, the scientific armamentarium sometimes seems to be poor and this could be explained by the fact that treatment options are offered too late, since this condition is often detected late, entailing higher patients' risks. In fact, the later the diagnosis is made the poorer the prognosis is for cases of abnormal placentation. Given that abnormal placentation is constantly increasing, the scientific community should aim at early diagnosis and appropriate management of such cases based on the best evidence available. Future improvement of knowledge and practice lies in perspective, preferably randomized studies so that we obtain high quality of evidence which is still needed. The purpose of this study is to review the current literature and to update the available scientific knowledge on the topic of abnormal placentation which is an emerging issue which clinicians should learn to deal with, considering its continuous increase in the last years.

Magnetic resonance imaging is often misleading when used as an adjunct to ultrasound in the management of placenta accreta spectrum disorders

BACKGROUND

Magnetic resonance imaging is reported to have good sensitivity and specificity in the diagnosis of placenta accreta spectrum disorders, and is often used as an adjunct to ultrasound. But the additional utility of obtaining magnetic resonance imaging to assist in the clinical management of patients with placenta accreta spectrum disorders, above and beyond the information provided by ultrasound, is unknown.

OBJECTIVE

We aimed to determine whether magnetic resonance imaging provides data that may inform clinical management by changing the sonographic diagnosis of placenta accreta spectrum disorders.

STUDY DESIGN

In all, 78 patients with sonographic evidence or clinical suspicion of placenta accreta spectrum underwent magnetic resonance imaging of the abdomen and pelvis in orthogonal planes through the uterus utilizing T1- and T2-weighted imaging sequences at the University of Utah and the University of Colorado from 1997 through 2017. The magnetic resonance imaging was interpreted by radiologists with expertise in diagnosis of placenta accreta spectrum who had knowledge of the sonographic interpretation and clinical risk factors for placenta accreta spectrum disorders. The primary outcome was a change in diagnosis from sonographic interpretation that could alter clinical management, which was defined a priori. Diagnostic accuracy was verified by surgical and histopathologic diagnosis at the time of delivery.

RESULTS

A change in diagnosis that could potentially alter clinical management occurred in 28 (36%) cases. Magnetic resonance imaging correctly changed the diagnosis in 15 (19%), and correctly confirmed the diagnosis in 34 (44%), but resulted in an incorrect change in diagnosis in 13 (17%), and an incorrect confirmation of ultrasound diagnosis in 15 (21%). Magnetic resonance imaging was not more likely to change a diagnosis in the 24 cases of posterior and lateral placental location compared to anterior location (33% vs 37%, P = .84). Magnetic resonance imaging resulted in overdiagnosis in 23% and in underdiagnosis in 14% of all cases. When ultrasound suspected severe disease (percreta) in 14 cases, magnetic resonance imaging changed the diagnosis in only 2 cases. Lastly, the proportion of accurate diagnosis with magnetic resonance imaging did not improve over time (61-65%, P = .96 for trend) despite increasing volume and increasing numbers of changed diagnoses.

CONCLUSION

Magnetic resonance imaging resulted in a change in diagnosis that could alter clinical management of placenta accreta spectrum disorders in more than one third of cases, but when changed, the diagnosis was often incorrect. Given its high cost and limited clinical value, magnetic resonance imaging should not be used routinely as an adjunct to ultrasound in the diagnosis of placenta accreta spectrum until evidence for utility is clearly demonstrated by more definitive prospective studies.

Impact of targeted scanning protocols on perinatal outcomes in pregnancies at risk of placenta accreta spectrum or vasa previa

BACKGROUND

Placenta accreta spectrum and vasa previa (VP) are congenital disorders of placentation associated with high morbidity and mortality for both mothers and newborns when undiagnosed before delivery. Prenatal diagnosis of these conditions is essential to allow multidisciplinary management and thus improve perinatal outcomes.

OBJECTIVE

The objective of the study was to compare perinatal outcome in women with placenta accreta spectrum or vasa previa before and after implementation of targeted scanning protocols.

STUDY DESIGN

This retrospective study included 2 nonconcurrent cohorts for each condition before and after implementation of the corresponding protocols (2004-1012 vs 2013-2016 for placenta accreta spectrum and 1988-2007 vs 2008-2016 for vasa previa). Clinical reports of women diagnosed with placenta accreta spectrum and vasa previa during the study periods were reviewed and outcomes were compared.

RESULTS

In total, there were 97 cases of placenta accreta spectrum and 51 cases with vasa previa, all confirmed at delivery. In both cohorts, the prenatal detection rate increased after implementation of the scanning protocols (28 of 65 cases [43.1%] vs 31 of 32 cases [96.9%], P < .001, for placenta accreta spectrum and 9 of 18 cases [50%] vs 29 of 33 cases [87.9%], 87.9%, P < .01 for vasa previa). The perinatal outcome improved also significantly in both cohorts after implementation of the protocols. In the placenta accreta spectrum cohort, the estimated blood loss and the postoperative hospitalization stay decreased between periods (1520 ± 845 vs 1168 ± 707 mL, P < .01, and 10.9 ± 14.1 vs 5.7 ± 2.2 days, P < .05, respectively). In the vasa previa cohort, the number of 5 minute Apgar score ≤5 and umbilical cord pH <7 decreased between periods (5 of 18 cases [27.8%] vs 1 of 33 cases [3%]; P < .05, and 4 of 18 cases [22.2%] vs 1 of 33 cases [3%], P < .05, respectively).

CONCLUSION

The implementation of standardized prenatal targeted scanning protocols for pregnant women with risk factors for placenta accreta spectrum and vasa previa was associated with improved maternal and neonatal outcomes. The continuous increases in the rates of caesarean deliveries and use of assisted reproductive technology highlights the need to develop training programs and introduce targeted scanning protocols at the national and international levels.

A clinico-pathologic study of placenta percreta

OBJECTIVE

To review a single-center case series of placenta percreta and to evaluate risk factors and the impact of surgical techniques used in previous cesarean delivery.

METHODS

The present retrospective cohort study included pregnancies with placenta percreta managed between January 1, 2002, and March 31, 2017, at Saint Luc University Hospital, Brussels, Belgium. The data reviewed included demographics, outcomes, inter-pregnancy interval, and surgical techniques used for uterine closure in previous cesarean delivery. A cases series of non-accreta placenta previa was used as a control group.

RESULTS

There were 19 pregnancies included in the study. The most common ultrasonography signs in the study group were loss of the clear zone (14/17; 82%), placental lacunae (17/17; 100%), and subplacental hypervascularity (11/14; 79%). Median gravidity, parity, and number of previous cesarean deliveries were higher (P<0.05) and inter-pregnancy interval was longer (P<0.05) in the study group than the control group. There was no difference between the groups in the surgical techniques used for previous cesarean deliveries.

CONCLUSION

The prenatal ultrasonography diagnosis of placenta percreta is accurate and facilitates optimal management by a specialized multidisciplinary team. Multicenter studies are required to further evaluate the impact of the surgical techniques used for prior cesarean delivery on the risks of placenta percreta in subsequent pregnancies.

Successful anticoagulant therapy for disseminated intravascular coagulation during conservative management of placenta percreta: a case report and literature review

Background

Placenta percreta is a rare obstetric condition associated with the risk of massive intraoperative hemorrhage. Recently, conservative management of placenta percreta has been performed to reduce maternal morbidity. However, various complications have been reported during such management. Only a few cases of asymptomatic disseminated intravascular coagulation (DIC) or fever without infection have been reported. Here, we discuss such a case and review the related literature to understand this rare condition better. For this, we performed an electronic literature review.

Case presentation

We present the clinical course, results of blood tests, and serial magnetic resonance images of a 35-year-old female (gravida 5, para 2) with placenta percreta complicated by placenta previa that was managed conservatively. The patient successfully delivered a healthy baby by a cesarean delivery via a transverse uterine fundal incision at 36 weeks of gestation. We did not observe intraoperative complications during cesarean delivery, and the postoperative course remained uncomplicated until 47 days after the delivery. However, asymptomatic DIC developed after 47 days, and her serum fibrinogen level declined to 42 mg/dL, which was successfully treated with anticoagulant therapy by a therapeutic dose of intravenous heparin for 22 days (postoperative days 48–69). Although DIC resolved, subsequent fever persisted for approximately 1 month (postoperative days 67–103). Infection was ruled out, and conservative management was successfully continued.

Literature review revealed that successful conservative management of a patient with asymptomatic DIC and subsequent fever without infection is extremely rare.

Conclusions

Some patients with DIC and fever can continue conservative management of placenta percreta, although careful examination and monitoring are needed.

The importance of bladder volume in the ultrasound diagnosis of placenta accreta spectrum disorders

OBJECTIVE

To assess how a quantifiable measure of vascularity-i.e. abnormal confluence (A_con ) in the subplacental myometrium observed by three-dimensional power-Doppler ultrasonography-changes with different bladder volumes.

METHODS

In a prospective observational study, women referred to a tertiary UK center with suspected PAS disorders were recruited between August 2016 and May 2017. The largest area of confluent three-dimensional power-Doppler signal (A_con ) at the uteroplacental interface was estimated under two bladder volumes differing by at least 200 mL.

RESULTS

A_con was calculated for 14 women, of whom seven were subsequently found to have PAS disorders. For these seven women, log(A_con ) was significantly greater when measured with a filled bladder than when measured with an unfilled bladder (P<0.001).

CONCLUSION

Objective evidence was found for a quantifiable difference in vascularity in the myometrium with bladder volume among women with PAS disorders. This difference has sufficient magnitude to influence the potential of A_con as a diagnostic marker.

The depletion of MARVELD1 leads to murine placenta accreta via integrin β4-dependent trophoblast cell invasion

The placenta is a remarkable organ, it serves as the interface between the mother and the fetus. Proper invasion of trophoblast cells is required for a successful pregnancy. Previous studies have found that the adhesion molecule integrin β4 plays important roles during trophoblast cell invasion. Here, we found that the overall birth rate of the MARVELD1 knockout mouse is much lower than that of the wild-type mouse (p < 0.001). In E18.5 MARVELD1 knockout mice, we observed an over-invasion of trophoblast cells, and indeed, the pregnant mice had a partial placenta accreta phenotype. The HTR8/SVneo cell line was used as an in vitro model to elucidate the underlying mechanisms of MARVELD1-mediated trophoblast invasion. We detected a diminished expression of integrin β4 upon the downregulation of MARVELD1 and enhanced migrate and invasive abilities of trophoblast cells both in vivo and in vitro. The integrin β4 rescue assay also supported the results. In conclusion, this study found that MARVELD1 mediated the invasion of trophoblast cells via regulating the expression of integrin β4 during placenta development.