Prevalence of fetal anomalies, stillbirth, neonatal morbidity, or mortality in pregnancies complicated by placenta accreta spectrum disorders.

INTRODUCTION: Placenta accreta spectrum disorders (PAS) lead to major complications in pregnancy. While the maternal morbidity associated with PAS is well known, there is less information regarding neonatal morbidity in this setting. The aim of this study is to describe the neonatal outcomes (fetal malformations, neonatal morbidity, twin births, stillbirth, and neonatal death), using an international multicenter database of PAS cases. MATERIAL AND METHODS: This was a prospective, multicenter cohort study based on prospectively collected cases, using the international multicenter database of the International Society for PAS, carried out between January 2020 and June 2022 by 23 centers with experience in PAS care. All PAS cases were included, regardless of whether singleton or multiple pregnancies and were managed in each center according to their own protocols. Data were collected via chart review. Local Ethical Committee approval and Data Use Agreements were obtained according to local policies. RESULTS: There were 315 pregnancies eligible for inclusion, with 12 twin pregnancies, comprising 329 fetuses/newborns; 2 cases were excluded due to inconsistency of data regarding fetal abnormalities. For the calculation of neonatal morbidity and mortality, all elective pregnancy terminations were excluded, hence 311 pregnancies with 323 newborns were analyzed. In our cohort, 3 neonates (0.93%) were stillborn; of the 320 newborns delivered, there were 10 cases (3.13%) of neonatal death. The prevalence of major congenital malformations was 4.64% (15/323 newborns), most commonly, cardiovascular, central nervous system, and gastrointestinal tract malformations. The overall prevalence of major neonatal morbidity in pregnancies complicated by PAS was 47/311 (15.1%). There were no stillbirths, neonatal deaths, or fetal malformations in reported twin gestations. CONCLUSIONS: Although some outcomes may be too rare to detect within our cohort and data should be interpreted with caution, our observational data supports reassuring neonatal outcomes for women with PAS.

Usefulness of low-cost simulation models to learning surgical techniques for placenta accreta spectrum: An observational educational study.

OBJECTIVE: To evaluate the utility of low-cost simulation models to teach surgical techniques for placenta accreta spectrum (PAS), included in a multimodal education workshop for PAS. METHODS: This was an observational, survey-based study. Participants were surveyed before and after the use of low-fidelity mannequins to simulate two surgical techniques for PAS (one-step conservative surgery [OSCS] and modified subtotal hysterectomy [MSTH]), within a multimodal educational workshop. The workshops included pre-course preparation, didactics, simulated practice of the techniques using low-cost models, and viewing live surgery. RESULTS: Six OSCS/MSTH training workshops occurred across six countries and a total of 270 participants were surveyed. The responses of 127 certified obstetricians and gynecologists (OB-GYNs) were analyzed. Participants expressed favorable impressions of all components of the simulated session. Perceived anatomical simulator fidelity, scenario realism, educational component effectiveness, and self-assessed performance improvement received ratings of 4-5 (positive end of the Likert scale) from over 90% of respondents. When asked about simulation's role in technique comprehension, comfort level in technique performance, and likelihood of recommending this workshop to others, more than 75% of participants rated these aspects with a score of 4-5 (positively) on the five-point scale. CONCLUSION: Low-cost simulation, within a multimodal education strategy, is a well-accepted intervention for teaching surgical techniques for PAS.

Opportunities for, and barriers to, uterus-preserving surgical techniques for placenta accreta spectrum.

INTRODUCTION: Placenta accreta spectrum (PAS) can lead to major peripartum morbidity. Appropriate management approaches depend on the clinical severity, each individual's preference, and the treating team's expertise. Peripartum hysterectomy is the most frequently used treatment option. However, it can impact psychological well-being and fertility. We investigated whether conservative treatment with focal resection or leaving the placenta in situ is associated with comparable or lower maternal morbidity than hysterectomy in centers of excellence within the International Society for placenta accreta spectrum (IS-PAS). Furthermore, a survey was conducted to explore potential barriers to conservative management in antenatal counseling and intraoperative decision-making. MATERIAL AND METHODS: Confirmed PAS cases in the prospective IS-PAS database from 22 registered centers between January 2020 and June 2022 were included in the analysis. A separate online survey with 21 questions was answered by the IS-PAS center experts about indications, diagnostic criteria, patient counseling, surgical practice, changes from the preoperative treatment plan, and why conservative management may not be offered. RESULTS: A total of 234 cases were included in the analysis: 186 women received hysterectomy and 38 women were treated by focal resection, and 10 by leaving the placenta in situ. Blood loss was lower in the focal resection group and in the placenta in situ group compared to the hysterectomy group (p = 0.04). 46.4% of the women initially planned for focal resection, and 35.7% of those initially planned for leaving the placenta in situ were ultimately treated by hysterectomy. Our survey showed that the IS-PAS centers preferred hysterectomy according to a woman's wishes (64%) and when they expected less blood loss and morbidity (41%). Eighteen percent of centers did not offer focal resection at all due to a lack of experience with this technique. Reasons for not offering to leave the placenta in situ were avoidance of unexpected reoperation (36%), puerperal infection (32%), or skepticism about the method (23%). CONCLUSIONS: Uterus-preserving treatment strategies such as focal resection appear to be safe alternatives to peripartum hysterectomy. However, less than half of the IS-PAS centers perform them. Acceptance of conservative treatments could be increased by standardized criteria for their implementation and by systematic training for PAS experts.

Are international guideline recommendations for the management of placenta accreta spectrum applicable in low- and middle-income countries?

OBJECTIVE: The aim of this study was to explore how obstetricians-gynecologists in low- and middle-income countries (LMICs) can apply current international clinical practice guidelines (CPGs) for the management of placenta accreta spectrum (PAS) in limited resource settings. METHODS: This was an observational, survey-based study. Clinicians with expertise in managing patients with PAS in LMICs were contacted for their evaluation of the recommendations included in four PAS clinical practice guidelines. RESULTS: Out of the 158 clinicians contacted, we obtained responses from 65 (41.1%), representing 27 middle income countries (MICs). The results of this survey suggest that the care of PAS patients in middle income countries is very different from what is recommended by international CPGs. Participants in the survey identified that their practice was limited by insufficient availability of hospital infrastructure, low resources of local health systems and lack of trained multidisciplinary teams (MDTs) and this did not enable them to follow CPG recommendations. Two-thirds of the participants surveyed describe the absence of centers of excellence in their country. In over half of the referral hospitals with expertise in managing PAS, there are no MDTs. One-third of patients with intraoperative findings of PAS are managed by the team initially performing the surgery (without additional assistance). CONCLUSION: The care of patients with PAS in middle income countries frequently deviates from established CPG recommendations largely due to limitations in local resources and infrastructure. New practical guidelines and training programs designed for low resource settings are needed.

Is telehealth useful in the management of placenta accreta spectrum in low-resource settings? Results of an exploratory survey.

OBJECTIVE: The optimal management of placenta accreta spectrum (PAS) requires the participation of multidisciplinary teams that are often not locally available in low-resource settings. Telehealth has been increasingly used to manage complex obstetric conditions. Few studies have explored the use of telehealth for PAS management, and we aimed evaluate the usage of telehealth in the management of PAS patients in low-resource settings. METHODS: Between March and April 2023, an observational, survey-based study was conducted, and obstetricians-gynecologists with expertise in PAS management in low- and middle-income countries were contacted to share their opinion on the potential use of telehealth for the diagnosis and management of patients at high-risk of PAS at birth. Participants were identified based on their authorship of at least one published clinical study on PAS in the last 5 years and contacted by email. This is a secondary analysis of the results of that survey. RESULTS: From 158 authors contacted we obtained 65 responses from participants in 27 middle-income countries. A third of the participants reported the use of telehealth during the management obstetric emergencies (38.5%, n = 25) and PAS (36.9%, n = 24). Over 70% of those surveyed indicated that they had used "informal" telemedicine (phone call, email, or text message) during PAS management. Fifty-nine participants (90.8%) reported that recommendations given remotely by expert colleagues were useful for management of patients with PAS in their setting. CONCLUSION: Telehealth has been successfully used for the management of PAS in middle-income countries, and our survey indicates that it could support the development of specialist care in other low resource settings.

Placenta accreta spectrum care infrastructure: an evidence-based review of needed resources supporting placenta accreta spectrum care.

The incidence of placenta accreta spectrum, the deeply adherent placenta with associated increased risk of maternal morbidity and mortality, has seen a significant rise in recent years. Therefore, there has been a rise in clinical and research focus on this complex diagnosis. There is international consensus that a multidisciplinary coordinated approach optimizes outcomes. The composition of the team will vary from center to center; however, central themes of complex surgical experts, specialists in prenatal diagnosis, critical care specialists, neonatology specialists, obstetrics anesthesiology specialists, blood bank specialists, and dedicated mental health experts are universal throughout. Regionalization of care is a growing trend for complex medical needs, but the location of care alone is just a starting point. The goal of this article is to provide an evidence-based framework for the crucial infrastructure needed to address the unique antepartum, delivery, and postpartum needs of the patient with placenta accreta spectrum. Rather than a clinical checklist, we describe the personnel, clinical unit characteristics, and breadth of contributing clinical roles that make up a team. Screening protocols, diagnostic imaging, surgical and potential need for critical care, and trauma-informed interaction are the basis for comprehensive care. The vision from the author group is that this publication provides a semblance of infrastructure standardization as a means to ensure proper preparation and readiness.

Delivery outcomes in the subsequent pregnancy following the conservative management of placenta accreta spectrum disorder: a systematic review and meta-analysis.

OBJECTIVE: Cesarean hysterectomy is generally presumed to decrease maternal morbidity and mortality secondary to placenta accreta spectrum disorder. Recently, uterine-sparing techniques have been introduced in conservative management of placenta accreta spectrum disorder to preserve fertility and potentially reduce surgical complications. However, despite patients often expressing the intention for future conception, few data are available regarding the subsequent pregnancy outcomes after conservative management of placenta accreta spectrum disorder. Thus, we aimed to perform a systematic review and meta-analysis to assess these outcomes. DATA SOURCES: PubMed, Scopus, and Web of Science databases were searched from inception to September 2022. STUDY ELIGIBILITY CRITERIA: We included all studies, with the exception of case studies, that reported the first subsequent pregnancy outcomes in individuals with a history of placenta accreta spectrum disorder who underwent any type of conservative management. METHODS: The R programming language with the "meta" package was used. The random-effects model and inverse variance method were used to pool the proportion of pregnancy outcomes. RESULTS: We identified 5 studies involving 1458 participants that were eligible for quantitative synthesis. The type of conservative management included placenta left in situ (n=1) and resection surgery (n=1), and was not reported in 3 studies. The rate of placenta accreta spectrum disorder recurrence in the subsequent pregnancy was 11.8% (95% confidence interval, 1.1-60.3; I2=86.4%), and 1.9% (95% confidence interval, 0.0-34.1; I2=82.4%) of participants underwent cesarean hysterectomy. Postpartum hemorrhage occurred in 10.3% (95% confidence interval, 0.3-81.4; I2=96.7%). A composite adverse maternal outcome was reported in 22.7% of participants (95% confidence interval, 0.0-99.4; I2=56.3%). CONCLUSION: Favorable pregnancy outcome is possible following successful conservation of the uterus in a placenta accreta spectrum disorder pregnancy. Approximately 1 out of 4 subsequent pregnancies following conservative management of placenta accreta spectrum disorder had considerable adverse maternal outcomes. Given such high incidence of adverse outcomes and morbidity, patient and provider preparation is vital when managing this population.

Surgical Techniques for the Management of Placenta Accreta Spectrum.

The surgical management of placenta accreta spectrum (PAS) is often challenging. There are a variety of techniques and management options described in the literature ranging from uterine sparing to cesarean hysterectomy. Following the inaugural meeting of the Pan-American Society for Placenta Accreta Spectrum a multidisciplinary group collaborated to describe collective recommendations for the surgical management of PAS. In this manuscript, we outline individual components of the procedure and provide suggested direction at key points of a cesarean hysterectomy in the setting of PAS. KEY POINTS: · The surgical management of PAS requires careful planning and expertise.. · Multidisciplinary team care for pregnancies complicated by PAS can decrease morbidity and mortality.. · Careful surgical techniques can minimize risk of significant hemorrhage by avoiding pitfalls..

Graduate and Continuing Medical Education of Placenta Accreta Spectrum.

Surgical training experience in obstetrics-gynecology (OB-GYN) residency and fellowship training, particularly in open abdominal surgeries has declined over the last 2 decades. This is due, in part, due to a universal trend toward non-invasive treatments for gynecologic conditions once treated surgically. Management of placenta accreta spectrum (PAS) often requires complex surgical skills, including, but not limited to highly complex hysterectomy. The decline in surgical case numbers has fallen as the incidence of PAS has risen, which we anticipate will lead to a gap in critical skills needed for graduating obstetrician-gynecologists to able to safely care for people with PAS.

Imaging the Uterus in Placenta Accreta Spectrum Disorder.

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

General Management Considerations for Placenta Accreta Spectrum.

The ideal management of a patient with placenta accreta spectrum (PAS) includes close antepartum management culminating in a planned and coordinated delivery by an experienced multidisciplinary PAS team. Coordinated team management has been shown to optimize outcomes for mother and infant. This section provides a consensus overview from the Pan-American Society for the Placenta Accreta Spectrum regarding general management of PAS.

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

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

A Retrospective Review of Social Deprivation Index and Maternal Outcomes with Placenta Accreta Spectrum from a Single Referral Center.

OBJECTIVE: Little is known about how community characteristics influence placenta accreta spectrum (PAS) outcomes. Our objective was to evaluate whether adverse maternal outcomes among pregnant people (gravidae) with PAS delivering at a single referral center differ by community-level measures of social deprivation. STUDY DESIGN: We conducted a retrospective cohort study of singleton gravidae with histopathology confirmed PAS delivering from January 2011 to June 2021 at a referral center. Data abstraction collected relevant patient information, including resident zip code, which was linked to Social Deprivation Index (SDI) score (a measure of area-level social deprivation). SDI scores were divided into quartiles for analysis. Primary outcome was a composite of maternal adverse outcomes. Bivariate analyses and multivariable logistic regression were performed. RESULTS: Among our cohort (n = 264), those in the lowest (least deprived) SDI quartile were older, had lower body mass index, and were more likely to identify as non-Hispanic white. Composite maternal adverse outcome occurred in 81 (30.7%), and did not differ significantly by SDI quartile. Intraoperative transfusion of ≥4 red blood cell units occurred more often among those living in deprived areas (31.2% in the highest [most deprived] vs. 22.7% in the lowest [least deprived] SDI quartile, p = 0.04). No other outcomes differed by SDI quartile. In multivariable logistic regression, a quartile increase in SDI was associated with 32% increased odds of transfusion of ≥4 red blood cell units (adjusted odds ratio: 1.32, 95% confidence interval: 1.01-1.75). CONCLUSION: Within a cohort of gravidae with PAS delivered at a single referral center, we found that those living in more socially deprived communities were more likely to receive transfusion of ≥4 red blood cell units, but other maternal adverse outcomes did not differ. Our findings highlight the importance of considering how characteristics of the surrounding community can impact PAS outcomes and may assist with risk stratification and resource deployment. KEY POINTS: · Little is known about how community characteristics influence PAS outcomes.. · In a referral center, transfusion was more common in gravidae living in socially deprived areas.. · Future research should consider how community characteristics can impact PAS outcomes..

Perinatal assessment of complex cesarean delivery: beyond placenta accreta spectrum.

Multiple cesarean deliveries are known to be associated with long-term postoperative consequences because of a permanent defect of the lower uterine segment wall and the development of thick pelvic adhesions. Patients with a history of multiple cesarean deliveries often present with large cesarean scar defects and are at heightened risk in subsequent pregnancies of cesarean scar ectopic pregnancy, uterine rupture, low-lying placenta or placenta previa, and placenta previa accreta. Moreover, large cesarean scar defects will lead to progressive dehiscence of the lower uterine segment with the inability to effectively reapproximate hysterotomy edge and repair at birth. Major remodeling of the lower uterine segment associated with true placenta accreta spectrum at birth, whereby the placenta becomes inseparable from the uterine wall, increases the rates of perinatal morbidity and mortality, especially when undiagnosed before delivery. Ultrasound imaging is currently not routinely used to evaluate the surgical risks of patients with a history of multiple cesarean deliveries, beyond the risk assessment of placenta accreta spectrum. Independent of accreta placentation, a placenta previa under a scarred, thinned partially disrupted lower uterine segment, covered by thick adhesions with the posterior wall of the bladder, poses a surgical risk and requires fine dissection and surgical expertise; however, data on the use of ultrasound to evaluate uterine remodeling and adhesions between the uterus and other pelvic organs are scarce. In particular, transvaginal sonography has been underused, including in patients with a high probability of placenta accreta spectrum at birth. Based on the best available knowledge, we discuss the role of ultrasound imaging in identifying the signs suggestive of major remodeling of the lower uterine segment and in mapping the changes in the uterine wall and pelvis, to enable the surgical team to prepare for all different types of complex cesarean deliveries. The need for postnatal confirmation of the prenatal ultrasound findings for all patients with a history of multiple cesarean deliveries, regardless of the diagnosis of placenta previa and placenta accreta spectrum, is discussed. We propose an ultrasound imaging protocol and a classification of the level of surgical difficulty at elective cesarean delivery to stimulate further research toward the validation of ultrasound signs by which these signs may be applied to improve surgical outcomes.

Feasibility Study of Ferumoxtyol for Contrast-enhanced MRI of Retroplacental Clear Space Disruption in Placenta Accreta Spectrum (PAS).

Introduction: Placenta accreta spectrum (PAS) occurs when the placenta is pathologically adherent to the myometrium. An intact retroplacental clear space (RPCS) is a marker of normal placentation, but visualization with conventional imaging techniques is a challenge. In this study, we investigate use of an FDA-approved iron oxide nanoparticle, ferumoxytol, for contrast-enhanced magnetic resonance imaging of the RPCS in mouse models of normal pregnancy and PAS. We then demonstrate the translational potential of this technique in human patients presenting with severe PAS (FIGO Grade 3C), moderate PAS (FIGO Grade 1), and no PAS. Methods: A T1-weighted gradient recalled echo (GRE) sequence was used to determine the optimal dose of ferumoxytol in pregnant mice. Pregnant Gab3 -/- mice, which demonstrate placental invasion, were then imaged at day 16 of gestation alongside wild-type (WT) pregnant mice which do not demonstrate invasion. Signal-to-noise ratio (SNR) was computed for placenta and RPCS for all fetoplacental units (FPUs) with ferumoxytol-enhanced magnetic resonance imaging (Fe-MRI) and used for the determination of contrast-to-noise ratio (CNR). Fe-MRI was also performed in 3 pregnant subjects using standard T1 and T2 weighted sequences and a 3D magnetic resonance angiography (MRA) sequence. RPCS volume and relative signal were calculated in all three subjects. Results: Ferumoxytol administered at 5 mg/kg produced strong T1 shortening in blood and led to strong placental enhancement in Fe-MRI images. Gab3 -/- mice demonstrated loss of hypointense region characteristic of the RPCS relative to WT mice in T1w Fe-MRI. CNR between RPCS and placenta was lower in FPUs of Gab3 -/- mice compared to WT mice, indicating higher degrees of vascularization and interruptions throughout the space. In human patients, Fe-MRI at a dose of 5 mg/kg enabled high uteroplacental vasculature signal and quantification of the volume and signal profile in severe and moderate invasion of the placenta relative to a non-PAS case. Discussion: Ferumoxytol, an FDA-approved iron oxide nanoparticle formulation, enabled visualization of abnormal vascularization and loss of uteroplacental interface in a murine model of PAS. The potential of this non-invasive visualization technique was then further demonstrated in human subjects. Diagnosis of placental invasion using Fe-MRI may provide a sensitive method for clinical detection of PAS.

Placenta Accreta Spectrum: Correlation between FIGO Clinical Classification and Histopathologic Findings.

OBJECTIVE: Placenta accreta spectrum (PAS) covers a wide spectrum of placental adherence/invasion with varied clinical significance. Histopathologic examination is considered the confirmatory gold standard, but is only obtained sometime after definitive treatment. The International Federation of Gynecology and Obstetrics (FIGO) has published a new clinical classification that can be assigned at delivery, and we aimed to investigate the association between this new FIGO classification and histopathology and also to assess its correlation with maternal outcomes. STUDY DESIGN: We studied a retrospective cohort of 185 patients with histopathologically proven PAS managed at our referral center between September 2012 and January 2019. Two experienced surgeons retrospectively reviewed charts and assigned the FIGO grading based on findings reported at delivery. A third experienced reviewer adjudicated to determine the classification used for final analysis. Categorical outcomes were compared with the use of chi-squared and the Fisher exact test, as appropriate. A multivariate model was designed to adjust outcomes in different FIGO groups for the involvement of a formal multidisciplinary management team. RESULTS: Among 185 patients, there were 41 (22%) placenta accreta, 44 (24%) placenta increta, and 100 (54%) placenta percreta on histopathology. The inter-rater reliability was found to be substantial with Kappa = 0.661 (p < 0.001), and 95% confidence interval (CI): 0.449-0.872. There was a significant association between all histopathology groupings and the FIGO clinical classification (p < 0.001). However, we found no association between FIGO classifications and maternal complications. CONCLUSION: The new FIGO clinical classification is strongly associated with histopathologic findings. A better understanding of the depth and extent of invasion as afforded by the clinical classification system will help standardize reporting and future research. KEY POINTS: · PAS includes a wide spectrum of placental invasion with varied clinical significance.. · Histopathological examination is considered the confirmatory gold standard.. · The new FIGO clinical classification is strongly associated with histopathologic findings..

The Association between Placenta Accreta Spectrum Severity and Incidence of Small for Gestational Age Neonates.

OBJECTIVE: The aim of the study is to evaluate whether pathologic severity of placenta accreta spectrum (PAS) is correlated with the incidence of small for gestational age (SGA) and neonatal birthweight. STUDY DESIGN: This was a multicenter cohort study of viable, non-anomalous, singleton gestations delivered with histology-proven PAS. Data including maternal history, neonatal birthweight, and placental pathology were collected and deidentified. Pathology was defined as accreta, increta, or percreta. The primary outcome was rate of SGA defined by birth weight less than the 10th percentile. The secondary outcomes included incidence of large for gestational age (LGA) babies as defined by birth weight greater than the 90th percentile as well as incidence of SGA and LGA in preterm and term gestations. Statistical analysis was performed using Chi-square, Kruskal-Wallis, and log-binomial regression. Increta and percreta patients were each compared with accreta patients. RESULTS: Among the cohort of 1,008 women from seven United States centers, 865 subjects were included in the analysis. The relative risk (RR) of SGA for increta and percreta did not differ from accreta after adjusting for confounders (adjusted RR = 0.63, 95% confidence interval [CI]: 0.36-1.10 for increta and aRR = 0.72, 95% CI: 0.45-1.16 for percreta). The results were stratified by placenta previa status, which did not affect results. There was no difference in incidence of LGA (p = 1.0) by PAS pathologic severity. The incidence of SGA for all PAS patients was 9.2% for those delivered preterm and 18.7% for those delivered at term (p = 0.004). The incidence of LGA for all PAS patients was 12.6% for those delivered preterm and 13.2% for those delivered at term (p = 0.8203). CONCLUSION: There was no difference in incidence of SGA or LGA when comparing accreta to increta or percreta patients regardless of previa status. Although we cannot suggest causation, our results suggest that PAS, regardless of pathologic severity, is not associated with pathologic fetal growth in the preterm period. KEY POINTS: · PAS severity is not associated with SGA in the preterm period.. · PAS severity is not associated with LGA.. · Placenta previa does not affect the incidence of SGA in women with PAS..

Nanoparticle Contrast-enhanced MRI for Visualization of Retroplacental Clear Space Disruption in a Mouse Model of Placental Accreta Spectrum (PAS).

INTRODUCTION: Prior preclinical studies established the utility of liposomal nanoparticle blood-pool contrast agents in visualizing the retroplacental clear space (RPCS), a marker of normal placentation, while sparing fetuses from exposure because the agent does not cross the placental barrier. In this work, we characterized RPCS disruption in a mouse model of placenta accreta spectrum (PAS) using these agents. MATERIALS AND METHODS: Contrast-enhanced MRI (CE-MRI) and computed tomography (CE-CT) using liposomal nanoparticles bearing gadolinium (liposomal-Gd) and iodine were performed in pregnant Gab3-/- and wild type (WT) mice at day 16 of gestation. CE-MRI was performed on a 1T scanner using a 2D T1-weighted sequence (100×100×600 µm3 voxels) and CE-CT was performed at a higher resolution (70×70×70 µm3 voxels). Animals were euthanized post-imaging and feto-placental units (FPUs) were harvested for histological examination. RPCS conspicuity was scored through blinded assessment of images. RESULTS: Pregnant Gab3-/- mice showed elevated rates of complicated pregnancy. Contrast-enhanced imaging demonstrated frank infiltration of the RPCS of Gab3-/- FPUs. RPCS in Gab3-/- FPUs was smaller in volume, demonstrated a heterogeneous signal profile, and received lower conspicuity scores than WT FPUs. Histology confirmed in vivo findings and demonstrated staining consistent with a thinner RPCS in Gab3-/- FPUs. DISCUSSION: Imaging of the Gab3-/- mouse model at late gestation with liposomal contrast agents enabled in vivo characterization of morphological differences in the RPCS that could cause the observed pregnancy complications. An MRI-based method for visualizing the RPCS would be valuable for early detection of invasive placentation.