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

OBJECTIVE

Clinical-sonographic scoring systems, combining clinical features and ultrasound imaging markers have been proposed for the screening of placenta accreta spectrum (PAS) but their usefulness in different set-ups remains limited. The aim of this study was to assess and compare different clinical-sonographic score systems performed from the midst of pregnancy for the prenatal evaluation of patients at risk of PAS at birth.

DATA SOURCES

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

STUDY ELIGIBILITY CRITERIA

Observational studies providing data on the use of a combined clinical-ultrasound score systems performed from the midst of pregnancy for the prenatal evaluation of PAS.

METHODS

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

RESULTS

Of 1028 articles reviewed, 12 cohorts and two case-control studies including 1630 patients screening for PAS by clinical-ultrasound scores met the eligibility criteria. A diagnosis of PAS was reported in 602 (36.9%) cases for which 547 (90.9%) intraoperative findings and/or histopathologic data were described. A wide variation in reported sensitivities and specificities was observed between studies and in thresholds used for the identification of patients with a high probability of PAS at birth. The SAUCs of the individual sonographic scores ranged between 0.85 (the lowest) for sub-placental hypervascularity to 0.91 for placental location in the lower uterine segment (LUS), myometrial thinning, and placental lacunae and 0.95 for the loss of clear zone. Only four studies included placental bulging in their sonographic score system and therefore no meta-analysis for this score was performed. The integrated SAUC was 0.83 [95% Confidence Interval (95% CI) 79 to 0.86). Forest Plot analysis revealed an integrated sensitivities and specificities of 0.68 [95% CI 0.53-0.80], and 0.88 [95% CI 0.68 to 0.96]), respectively.

CONCLUSIONS

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

Ambient air pollution and adverse birth outcomes: A review of underlying mechanisms

Epidemiological data provide varying degrees of evidence for associations between prenatal exposure to ambient air pollutants and adverse birth outcomes (suboptimal measures of fetal growth, preterm birth and stillbirth). To assess further certainty of effects, this review examines the experimental literature base to identify mechanisms by which air pollution (particulate matter, nitrogen dioxide and ozone) could cause adverse effects on the developing fetus. It likely that this environmental insult impacts multiple biological pathways important for sustaining a healthy pregnancy, depending upon the composition of the pollutant mixture and the exposure window owing to changes in physiologic maturity of the placenta, its circulations and the fetus as pregnancy ensues. The current body of evidence indicates that the placenta is a target tissue, impacted by a variety of critical processes including nitrosative/oxidative stress, inflammation, endocrine disruption, epigenetic changes, as well as vascular dysregulation of the maternal-fetal unit. All of the above can disturb placental function and, as a consequence, could contribute to compromised fetal growth as well increasing the risk of stillbirth. Furthermore, given that there is often an increased inflammatory response associated with preterm labour, inflammation is a plausible mechanism mediating the effects of air pollution on premature delivery. In the light of increased urbanisation and an ever-changing climate, both of which increase ambient air pollution and negatively affect vulnerable populations such as pregnant individuals, it is hoped that the collective evidence may contribute to decisions taken to strengthen air quality policies, reductions in exposure to air pollution and subsequent improvements in the health of those not yet born.

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.

Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus

BACKGROUND

There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies.

OBJECTIVE

This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique.

STUDY DESIGN

A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from "strongly disagree"=1 to "strongly agree"=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated.

RESULTS

A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa.

CONCLUSION

Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

Surgical evacuation combined with Shirodkar cervical suture and selective uterine artery embolization: A fertility preserving treatment for 10-15 weeks' live cesarean scar ectopic pregnancies

INTRODUCTION

Cesarean scar ectopic pregnancies (CSEPs) are associated with significant maternal morbidity and termination is often recommended in the early first trimester. Management of more advanced cases is challenging due to higher risks of major intraoperative hemorrhage. Hysterectomy is currently the intervention of choice for advanced cases. This study aimed to investigate if advanced live CSEPs could be managed effectively conservatively using suction curettage and interventional radiology.

MATERIAL AND METHODS

A retrospective single-center cohort study was performed. A total of 371 women diagnosed with CSEP were identified between January 2008 and January 2023. A total of 6% (22/371) women had an advanced live CSEP with crown-rump length (CRL) of ≥40 mm (≥10 weeks' gestation). Of these, 77% (17/22) opted for surgical intervention, whilst the remaining five continued their pregnancies. A preoperative ultrasound was performed in each patient. All women underwent suction curettage under ultrasound guidance and insertion of Shirodkar cervical suture as a primary hemostatic measure combined with uterine artery embolization (UAE) if required. The primary outcome was rate of blood transfusion. Secondary outcomes were estimated intraoperative blood loss, UAE, intensive care unit admission, reintervention, hysterectomy, hospitalization duration and rate of retained products of conception. Descriptive statistics were used to describe these variables.

RESULTS

Median CRL of the 17 patients included was 54.1 mm (range: 40.0-85.7) and median gestational age based on CRL was 12 + 3 weeks (range: 10 + 6-15 + 0). On preoperative ultrasound scan placental lacunae were recorded in 76% (13/17) of patients and color Doppler score was ≥3 in 67% (10/15) of patients. At surgery, Shirodkar cervical suture was used in all cases. It was successful in achieving hemostasis by tamponade in 76% (13/17) of patients. In the remaining 24% (4/17) patients tamponade failed to achieve complete hemostasis and UAE was performed to stop persistent arterial bleeding into the uterine cavity. Median intraoperative blood loss was 800 mL (range: 250-2500) and 41% (7/17) women lost >1000 mL. 35% (6/17) needed blood transfusion. No women required hysterectomy.

CONCLUSIONS

Surgical evacuation with Shirodkar cervical suture and selective UAE is an effective treatment for advanced live CSEPs.

Management of placenta accreta spectrum in low- and middle-income countries

Placenta accreta spectrum (PAS) can be associated massive intra- and post-operative hemorrhage which when not controlled can lead to maternal death. Important advances have occurred in understanding the pathophysiology and therapeutic options for this condition. The prevalence of PAS at birth is direct association with the cesarean delivery (CD) rate in the corresponding population and is increasing worldwide. Limited health infrastructure in low- and middle-income countries increases the morbidity and mortality of patients with PAS at birth. In many cases, obstetricians working in limited resources settings cannot follow some of the international guideline's recommendations and have to opt for low-cost management procedures. In this review, we describe the particularities of managing PAS care in low- and middle-income countries from of prenatal evaluation of patients at risk of PAS at birth, therapeutic options, and inter-institutional collaboration. We also propose a management protocol based on training of the local obstetric teams rather than on sophisticated technological resources that are almost never available in low-resource scenarios.

Placental lakes vs lacunae: spot the differences

Sonographic sonolucencies are anechoic areas surrounded by tissue of normal echogenicity, commonly found in the placental parenchyma during the second and third trimesters of pregnancy. The ultrasound appearance of lakes and lacunae derives from the low echogenicity of villous-free areas within the placental parenchyma, filled with maternal blood of varying velocities. In normal placentation, lakes usually start appearing as soon as maternal blood begins to flow freely within the intervillous space at the end of the first trimester, whereas, in accreta placentation, lacunae develop progressively during the second trimester. Larger lakes are found mainly in areas of lower villous density under the fetal plate or in the marginal areas, but can also be found in the center of a lobule above the entry of a spiral artery. Lakes of variable size, position and shape are of no clinical significance, except if they transform into echogenic cystic lesions, which have been associated with poor fetal growth and placental malperfusion. Lacunae are formed by the distortion of one or more placental lobules developing inside a uterine scar, resulting from high-volume, high-velocity flows from the radial/arcuate arteries, and are associated with a high probability of placenta accreta spectrum at birth. They often present with ultrasound signs of uterine remodeling following scarring. Lakes and lacunae can coexist within the same placenta and both will change in size and shape as pregnancy advances. Better understanding of the etiopathology of placental sonolucent spaces and associated morphological changes is necessary to identify patients at risk of subsequent complications during pregnancy and/or at delivery. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Evaluation of preoperative ultrasound signs associated with bladder injury during complex Cesarean delivery: a case-control study

OBJECTIVES

Intraoperative hemorraghe and peripartum hysterectomy are the main complications in patients presenting with a low-lying or placenta previa undergoing repeat cesarean delivery. Patients with a high probability of placenta accreta spectrum (PAS) at birth also have a higher risk of intraoperative urologic injuries and the aim of this study was to evaluate the ultrasound signs and intraoperative features associated with these injuries.

METHODS

This was a retrospective case-control study of consecutive singleton pregnancies included in a prospective cohort of patients with a history of at least one prior cesarean delivery (CD) and were diagnosed prenatally with an anterior low-lying or placenta previa at 32-36 weeks. All patients underwent investigational preoperative transabdominal and transvaginal ultrasound examinations within 48h prior to delivery. Ultrasound anomalies of uterine contour and utero-placental vascularity and gross anomalies of the lower uterine segment (LUS) and surrounding pelvic tissue at delivery were recorded using a standardised protocol including the evaluation of the size of anomalies of uterine contour. The diagnosis of PAS was established when one or more placental lobule(s) could not be digitally separated from the uterine wall at delivery or during the gross examination of the hysterectomy or partial myometrial resection specimens, confirmed by histopathology. Data were compared between cases complicated by intraoperative urologic injuries and three controls from the same cohort matched by parity and the number of prior cesarean deliveries using conditional logistic regression.

RESULTS

There were 16 (9.4%) patients with an intraoperative bladder injury out of a cohort of 170 patients managed by the same multidisciplinary team during the study period. There were no patients diagnosed with ureteric or bladder trigone damage. Fourteen patients (87.5%) with a bladder injury had histopathologic evidence of PAS at birth including 11 (68.8%) cases described on microscopic examination as placenta increta and three as placenta creta. There was a significant (p= 0.03) difference between cases and controls in the distribution of the intraoperative LUS vascularity with the higher the number of enlarged vessels the higher the odds ratio (OR) of bladder injury. The multivariable regression analysis revealed that both gestational age and LUS remodelling on transabdominal ultrasound were associated with a bladder injury. A longer gestational age was associated with a lower risk of an injury. A higher LUS remodelling grade on TAS was associated with an increased risk of bladder injury. Patients with a grade of 3 (involving > 50% of the LUS) had odds of a bladder injury that were 9 times higher than for patients with a grade of 1 (involving < 30% of the LUS).

CONCLUSIONS

Preoperative ultrasound examination is useful in the evaluation of the risk of the intraoperative bladder injury in patients with a history of prior CD presenting with a low-lying or placenta previa. The larger the remodelling of the LUS on transabdominal ultrasound the higher the risk of adverse urologic events. This article is protected by copyright. All rights reserved.

Antenatal fetal growth patterns in uncomplicated pregnancies according to mode of conception and placental location

Newborns resulting from in-vitro fertilisation (IVF) had a significantly (P= 0.002) higher birthweight centile than those resulting from spontaneous conception (SC) but no significant changes were found in ultrasound estimated fetal weight (EFW) centile between 20-22 and 32-34 weeks between the IVF and SC groups. When stratified for the IVF methods used, significant (P = 0.02) fastest in-utero fetal growth (mean increase in centile of 5 between 2nd to 3rd trimester) was observed in the frozen embryo transfer (FET) subgroup compared to SC, and to IVF pregnancies resulting from fresh blastocyst transfer (FBT) or from oocyte donation (OD). Low placentation was significantly (P < 0.001) more common in the IVF group than in the SC group but was not associated with a change in growth pattern suggesting that fetal growth in-utero is independent of placental location but may be influenced by embryo freezing.

Urological complications in women undergoing Cesarean section for placenta accreta spectrum disorders: systematic review and meta-analysis

OBJECTIVE

To report on the occurrence of urological complications in women undergoing Cesarean section for placenta accreta spectrum disorders (PAS).

METHODS

MEDLINE, EMBASE and the Cochrane databases were searched electronically up to 1 November 2022. Studies reporting on the urological outcome of women undergoing Cesarean section for PAS were included. Two independent reviewers performed data extraction using a predefined protocol and assessed the risk of bias using the Newcastle-Ottawa scale for observational studies, with disagreements resolved by consensus.The primary outcome was the overall occurrence of urological complications. Secondary outcomes were the occurrence of any cystotomy, intentional cystotomy, unintentional cystotomy, ureteral damage, ureteral fistula and vesicovaginal fistula. All outcomes were explored in the overall population of women undergoing surgery for PAS. In addition, we performed subgroup analyses according to the type of surgery (Cesarean hysterectomy, or conservative surgery or management), severity of PAS at histopathology (placenta accreta/increta and placenta percreta), type of intervention (planned vs emergency) and number of cases per year. Random-effects meta-analyses of proportions were used to analyze the data.

RESULTS

There were 62 studies included in the systematic review and 56 were included in the meta-analysis. Urological complications occurred in 15.2% (95% CI, 12.9-17.7%) of cases. Cystotomy complicated 13.5% (95% CI, 9.7-17.9%) of surgical operations. Intentional cystotomy was required in 7.7% (95% CI, 6.5-9.1%) of cases, while unintentional cystotomy occurred in 7.2% (95% CI, 6.0-8.5%) of cases. Urological complications occurred in 19.4% (95% CI, 16.3-22.7%) of cases undergoing hysterectomy and 12.2% (95% CI, 7.5-17.8%) of those undergoing conservative treatment. In the subgroup analyses, urological complications occurred in 9.4% (95% CI, 5.4-14.4%) of women with placenta accreta/increta and 38.5% (95% CI, 21.6-57.0%) of those described as having placenta percreta, and included mainly cystotomy (5.5% (95% CI, 0.6-15.1%) and 22.0% (95% CI, 5.4-45.5%), respectively). Urological complications occurred in 15.4% (95% CI, 8.1-24.6%) of cases undergoing a planned procedure and 24.6% (95% CI, 13.0-38.5%) of those undergoing an emergency intervention. In subanalysis of studies reporting on ≥ 12 cases per year, the incidence of urological complication was similar to that reported in the primary analysis.

CONCLUSIONS

Women undergoing surgery for PAS are at high risk of urological complication, mainly cystotomy. The incidence of these complications was particularly high in women described as having placenta percreta at birth and in those undergoing emergency surgical intervention. The high heterogeneity between the included studies highlights the need for a standardized protocol for the diagnosis of PAS to identify prenatal imaging signs associated with the increased risk of urological morbidity at delivery. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Use of super resolution reconstruction MRI for surgical planning in Placenta accreta spectrum disorder: Case series

INTRODUCTION

Comprehensive imaging using ultrasound and MRI of placenta accreta spectrum (PAS) aims to prevent catastrophic haemorrhage and maternal death. Standard MRI of the placenta is limited by between-slice motion which can be mitigated by super-resolution reconstruction (SRR) MRI. We applied SRR in suspected PAS cases to determine its ability to enhance anatomical placental assessment and predict adverse maternal outcome.

METHODS

Suspected PAS patients (n = 22) underwent MRI at a gestational age (weeks + days) of (32+3±3+2, range (27+1-38+6)). SRR of the placental-myometrial-bladder interface involving rigid motion correction of acquired MRI slices combined with robust outlier detection to reconstruct an isotropic high-resolution volume, was achieved in twelve. 2D MRI or SRR images alone, and paired data were assessed by four radiologists in three review rounds. All radiologists were blinded to results of the ultrasound, original MR image reports, case outcomes, and PAS diagnosis. A Random Forest Classification model was used to highlight the most predictive pathological MRI markers for major obstetric haemorrhage (MOH), bladder adherence (BA), and placental attachment depth (PAD).

RESULTS

At delivery, four patients had placenta praevia with no abnormal attachment, two were clinically diagnosed with PAS, and six had histopathological PAS confirmation. Pathological MRI markers (T2-dark intraplacental bands, and loss of retroplacental T2-hypointense line) predicting MOH were more visible using SRR imaging (accuracy 0.73), in comparison to 2D MRI or paired imaging. Bladder wall interruption, predicting BA, was only easily detected by paired imaging (accuracy 0.72). Better detection of certain pathological markers predicting PAD was found using 2D MRI (placental bulge and myometrial thinning (accuracy 0.81)), and SRR (loss of retroplacental T2-hypointense line (accuracy 0.82)).

DISCUSSION

The addition of SRR to 2D MRI potentially improved anatomical assessment of certain pathological MRI markers of abnormal placentation that predict maternal morbidity which may benefit surgical planning.

The role of transvaginal ultrasound in the third-trimester evaluation of patients at high risk of placenta accreta spectrum at birth

BACKGROUND

Transvaginal ultrasound imaging has become an essential tool in the prenatal evaluation of the lower uterine segment and anatomy of the cervix, but there are only limited data on the role of transvaginal ultrasound in the management of patients at high risk of placenta accreta spectrum at birth.

OBJECTIVE

This study aimed to evaluate the role of transvaginal sonography in the third trimester of pregnancy in predicting outcomes in patients with a high probability of placenta accreta spectrum at birth.

STUDY DESIGN

This was a retrospective analysis of prospectively collected data of patients presenting with a singleton pregnancy and a history of at least 1 previous cesarean delivery and patients diagnosed prenatally with an anterior low-lying placenta or placenta previa delivered electively after 32 weeks of gestation. All patients had a least 1 detailed ultrasound examination, including transabdominal and transvaginal scans, within 2 weeks before delivery. Of note, 2 experienced operators, blinded to the clinical data, were asked to make a judgment on the likelihood of placenta accreta spectrum as a binary, low or high-probability of placenta accreta spectrum, and to predict the main surgical outcome (conservative vs peripartum hysterectomy). The diagnosis of accreta placentation was confirmed when one or more placental cotyledons could not be digitally separated from the uterine wall at delivery or during the gross examination of the hysterectomy or partial myometrial resection specimens.

RESULTS

A total of 111 patients were included in the study. Abnormal placental tissue attachment was found in 76 patients (68.5%) at birth, and histologic examination confirmed superficial villous attachment (creta) and deep villous attachment (increta) in 11 and 65 cases, respectively. Of note, 72 patients (64.9%) had a peripartum hysterectomy, including 13 cases with no evidence of placenta accreta spectrum at birth because of failure to reconstruct the lower uterine segment and/or excessive bleeding. There was a significant difference in the distribution of placental location (X2=12.66; P=.002) between transabdominal and transvaginal ultrasound examinations, but both ultrasound techniques had similar likelihood scores in identifying accreta placentation that was confirmed at birth. On transabdominal scan, only a high lacuna score was significantly associated (P=.02) with an increased chance of hysterectomy, whereas on transvaginal scan, significant associations were found between the need for hysterectomy and the thickness of the distal part of the lower uterine segment (P=.003), changes in the cervix structure (P=.01), cervix increased vascularity (P=.001), and the presence of placental lacunae (P=.005). The odds ratio for peripartum hysterectomy were 5.01 (95% confidence interval, 1.25-20.1) for a very thin (<1-mm) distal lower uterine segment and 5.62 (95% confidence interval, 1.41-22.5) for a lacuna score of 3+.

CONCLUSION

Transvaginal ultrasound examination contributes to both prenatal management and the prediction of surgical outcomes in patients with a history of previous cesarean delivery with and without ultrasound signs suggestive of placenta accreta spectrum. Transvaginal ultrasound examination of the lower uterine segment and cervix should be included in clinical protocols for the preoperative evaluation of patients at risk of complex cesarean delivery.

Imaging in gynecological disease (25): clinical and ultrasound characteristics of intramural pregnancy

OBJECTIVE

To describe the clinical and sonographic characteristics of intramural pregnancy, as well as the available management options and treatment outcomes.

METHODS

This was a retrospective single-center study of consecutive patients with a sonographic diagnosis of intramural pregnancy between November 2008 and November 2022. An intramural pregnancy was diagnosed on ultrasound when a pregnancy was implanted within the uterine corpus, above the level of the internal cervical os and separate from the interstitial section of the Fallopian tube, and extended beyond the decidual-myometrial junction. Clinical, ultrasound, relevant surgical and histological information and outcomes were retrieved from each patient's record and analyzed.

RESULTS

Eighteen patients were diagnosed with an intramural pregnancy during the study period. Their median age was 35 (range, 28-43) years and the median gestational age at diagnosis was 8 + 1 (range, 5 + 5 to 12 + 0) weeks. Vaginal bleeding with or without abdominal pain was the most common presenting symptom, recorded in eight patients. Nine (50%) patients had a partial and nine (50%) had a complete intramural pregnancy. Embryonic cardiac activity was present in eight (44%) pregnancies. The majority of pregnancies (n = 10 (56%)) were initially managed conservatively, including expectant management in eight (44%) cases, local injection of methotrexate in one (6%) and embryocide in one (6%). Conservative management was successful in nine of the 10 (90%) pregnancies, with a median time to serum human chorionic gonadotropin resolution of 71 (range, 35-143) days. One patient with an ongoing live pregnancy had an emergency hysterectomy for a major vaginal bleed at 20 weeks' gestation. No other patient managed conservatively experienced any significant complication. The remaining eight (44%) patients had primary surgical treatment, comprising transcervical suction curettage in seven (88%) of these cases, while one patient presented with uterine rupture and underwent emergency laparoscopy and repair.

CONCLUSIONS

We describe the ultrasound features of partial and complete intramural pregnancy, demonstrating key diagnostic features. Our series suggests that, when intramural pregnancy is diagnosed before 12 weeks' gestation, it can be managed either conservatively or by surgery, with preservation of reproductive function in most women. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of ultrasound features of placenta accreta spectrum in women at high risk: association with outcome and interobserver concordance

OBJECTIVES

To evaluate the prenatal ultrasound features associated with operative complications and to assess the interobserver agreement of prenatal ultrasound assessment with histopathologic confirmation of placenta accreta spectrum (PAS) in a cohort of high-risk patients with detailed intraoperative and histopathologic data.

METHODS

This was a retrospective multicenter cohort study of patients at high risk of PAS referred for specialist perinatal care and management between January 2019 and May 2022. Deidentified ultrasound images were reviewed independently by two experienced operators blinded to clinical details, intraoperative features, outcome and histopathologic findings. The diagnosis of PAS was confirmed by failure of detachment of one or more placental cotyledons from the uterine wall at delivery, and the absence of decidua with distortion of the uteroplacental interface by fibrinoid deposition on histologic examination of the accretic areas obtained by guided sampling of partial myometrial resection or hysterectomy specimens. Patients were categorized as having a low or high likelihood of PAS at birth. Interobserver agreement of prenatal ultrasound assessment with histopathologic confirmation of PAS was assessed using the kappa statistic. Primary outcome was major operative morbidity (blood loss ≥ 2000 mL, unintentional injury to the viscera, admission to intensive care unit or death).

RESULTS

A total of 102 women at high risk of PAS were referred, of whom 66 had evidence of PAS at birth and 36 did not. When blinded to other clinical details, the examiners agreed on the low or high probability of PAS, according to ultrasound features, in 75/102 cases (73.5%). The kappa statistic was 0.47 (95% CI, 0.28-0.66), showing moderate agreement. Morbidity was twice as common with concordant prenatal diagnosis of PAS vs concordant diagnosis of not PAS. Concordant assessment of high probability of PAS was associated with the highest morbidity (66.6%) and a very high (97.6%) likelihood of histopathologic confirmation.

CONCLUSIONS

The probability of histopathologic confirmation is very high with concordant prenatal assessment suggestive of PAS. The interobserver agreement for preoperative assessment with histopathologic confirmation of PAS is only moderate. Morbidity is associated with both histopathologic diagnosis and concordant antenatal assessment of PAS. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Surgical evacuation of cesarean scar ectopic pregnancies

Cesarean scar ectopic pregnancy is associated with significant maternal morbidity, including severe hemorrhage, need for the blood transfusion and hysterectomy. Early diagnosis is therefore key in ensuring timely management, with consensus being that treatment before 9 weeks of gestation leads to reduced morbidity. There is no universally adopted management protocol for cesarean scar ectopic pregnancy, but surgical management generally has a higher success rate than medical management. The primary surgical treatment modalities are suction evacuation versus resection of the pregnancy via multiple routes. Adjuncts that have been shown to successfully minimize bleeding with surgical management include cervical cerclage, balloon catheter, and uterine artery embolization. However, there remains a lack of high-quality evidence regarding what is the best surgical treatment option for cesarean scar ectopic pregnancy, and therefore it is essential that clinicians provide tailored management to patients considering the presenting symptoms and local expertise with various surgical techniques.

Definition and diagnosis of cesarean scar ectopic pregnancies

Cesarean scar ectopic pregnancy is a rare type of ectopic pregnancy, where the pregnancy implants into a myometrial defect caused by a cesarean scar. Its incidence is predicted to increase, given the global increase in cesarean deliveries. As most cesarean scar ectopic pregnancies present as failing pregnancies or patients choose termination of pregnancy, there are limited data on their natural history. However, early first trimester diagnosis is essential, given the associated significant maternal morbidity. Transvaginal sonography is generally considered to be the optimal method for diagnosing cesarean scar ectopic pregnancy. There is no evidence that MRI adds to the diagnostic accuracy, and it is therefore not recommended for routine evaluation of cesarean scar ectopic pregnancy. There is no agreed reference standard for the diagnosis of cesarean scar ectopic pregnancy; therefore, the validity of several proposed sonographic diagnostic criteria reported by different authors remains unknown. There are also various suggested classification systems for cesarean scar ectopic pregnancy, which divide them in differet types. However, the proposals are very heterogeneous, and superiority of one classification system over another is yet to be established.

The human placenta: new perspectives on its formation and function during early pregnancy

The placenta has evolved to support the development of the embryo and fetus during the different intrauterine periods of life. By necessity, its development must precede that of the embryo. There is now evidence that during embryogenesis and organogenesis, the development of the human placenta is supported by histotrophic nutrition secreted from endometrial glands rather than maternal blood. These secretions provide a plentiful supply of glucose, lipids, glycoproteins and growth factors that stimulate rapid proliferation and differentiation of the villous trophoblast. Furthermore, evidence from endometrial gland organoids indicates that expression and secretion of these products are upregulated following sequential exposure to oestrogen, progesterone and trophoblastic and decidual hormones, in particular prolactin. Hence, a feed-forward signalling dialogue is proposed among the trophoblast, decidua and glands that enables the placenta to stimulate its own development, independent of that of the embryo. Many common complications of pregnancy represent a spectrum of disorders associated with deficient trophoblast proliferation. Increasing evidence suggests that this spectrum is mirrored by one of impaired decidualization, potentially compromising histotroph secretion through diminished prolactin secretion and reduced gland function. Optimizing endometrial wellbeing prior to conception may therefore help to prevent common pregnancy complications, such as miscarriage, growth restriction and pre-eclampsia.

Modified Delphi study of ultrasound signs associated with placenta accreta spectrum

OBJECTIVE

To determine, by expert consensus through a modified Delphi process, the role of standardized and new ultrasound signs in the prenatal evaluation of patients at high risk of placenta accreta spectrum (PAS).

METHODS

A systematic review of articles providing information on ultrasound imaging signs or markers associated with PAS was performed before the development of questionnaires for the first round of the Delphi process. Only peer-reviewed original research studies in the English language describing one or more new ultrasound sign(s) for the prenatal evaluation of PAS were included. A three-round consensus-building Delphi method was then conducted under the guidance of a steering group, which included nine experts who invited an international panel of experts in obstetric ultrasound imaging in the evaluation of patients at high risk for PAS. Consensus was defined as agreement of ≥ 70% between participants.

RESULTS

The systematic review identified 15 articles describing eight new ultrasound signs for the prenatal evaluation of PAS. A total of 35 external experts were approached, of whom 31 agreed and participated in the first round. Thirty external experts (97%) and seven experts from the steering group completed all three Delphi rounds. A consensus was reached that a prior history of at least one Cesarean delivery, myomectomy or PAS should be an indication for detailed PAS ultrasound assessment. The panelists also reached a consensus that seven of the 11 conventional signs of PAS should be included in the examination of high-risk patients and the routine mid-gestation scan report: (1) loss of the 'clear zone', (2) myometrial thinning, (3) bladder-wall interruption, (4) placental bulge, (5) uterovesical hypervascularity, (6) placental lacunae and (7) bridging vessels. A consensus was not reached for any of the eight new signs identified by the systematic review. With respect to other ultrasound features that are not specific to PAS but increase the probability of PAS at birth, the panelists reached a consensus for the finding of anterior placenta previa or placenta previa with cervical involvement. The experts were also asked to determine which PAS signs should be quantified and consensus was reached only for the quantification of placental lacunae using an existing score. For predicting surgical outcome in patients with a high probability of PAS at delivery, a consensus was obtained for loss of the clear zone, bladder-wall interruption, presence of placental lacunae and presence of placenta previa involving the cervix.

CONCLUSIONS

We have confirmed the continued importance of seven established standardized ultrasound signs of PAS, highlighted the role of transvaginal ultrasound in evaluating the placental position and anatomy of the cervix, and identified new ultrasound signs that may become useful in the future prenatal evaluation and management of patients at high risk for PAS at birth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

Correlation of IVF outcomes and number of oocytes retrieved: a UK retrospective longitudinal observational study of 172 341 non-donor cycles

OBJECTIVE

How do numbers of oocytes retrieved per In vitro fertilisation (IVF) cycle impact on the live birth rate (LBR) and multiple gestation pregnancy (MGP) rates?

DESIGN

Retrospective observational longitudinal study.

SETTING

UK IVF clinics.

POPULATION

Non-donor IVF patients.

MAIN OUTCOME MEASURES

LBR per IVF cycle and MGP levels against number of oocytes retrieved into subgroups: 0, 1-5, 6-15, 16-25, 26-49 oocytes and 50+ oocytes. Relative risk (RR) and 95% CIs were calculated for each group against the intermediate responder with '6-15 oocytes collected'.

RESULTS

From 172 341 attempted fresh oocyte retrieval cycles, the oocyte retrieved was: 0 in 10 148 (5.9%) cycles from 9439 patients; 1-5 oocytes in 42 574 cycles (24.7%); 6-15 oocytes in 91 797 cycles (53.3%); 16-25 oocytes in 23 794 cycles (13.8%); 26-49 oocytes in 3970 cycles (2.3%); ≥50 oocytes in 58 cycles (0.033%). The LBRs for the 1-5, 6-15, 16-25 and 26-49 subgroups of oocytes retrieved were 17.2%, 32.4%, 35.3% and 18.7%, respectively. The RR (95% CI) of live birth in comparison to the intermediate group (6-15) for 1-5, 16-25 and 26-49 groups was 0.53 (0.52 to 0.54), 1.09 (1.07 to 1.11) and 0.58 (0.54 to 0.62), respectively. The corresponding MGP rates and RR were 9.2%, 11.0%, 11.4% and 11.3%, respectively and 0.83 (0.77 to 0.90), 1.04 (0.97 to 1.11) and 1.03 (0.84 to 1.26), respectively.

CONCLUSION

There was only limited benefit in LBR beyond the 6-15 oocyte group going to the 16-25 oocytes group, after which there was significant decline in LBR. The MGP risk was lower in 1-5 group.

Ultrasound diagnosis of placental and umbilical cord anomalies in singleton pregnancies resulting from in-vitro fertilization

INTRODUCTION

placental anomalies can affect fetal and maternal outcome due to severe maternal hemorrhage potentially resulting in hysterectomy and cord accident including abruption that can determine fetal damage or death. The aims of our study are to determine if the rate of placental and umbilical cord anomalies are more common in IVF singleton pregnancies compared to spontaneous pregnancies; to evaluate the role of ultrasound in screening for these anomalies and to investigate if oocyte donor fertilization is an additional risk factor for the development of these anomalies.

METHODS

this was a prospective cohort study involving two tertiary centers. Patients with a singleton pregnancy conceived with IVF and patients presenting with a spontaneous conception were recruited between 1^st May 2019 to 31^st March 2021. A total of 634 pregnancies were enrolled in the study. All patients underwent similar antenatal care, which included ultrasound examinations at 11-14, 19-22 and 33-35 weeks. Ultrasound findings of placental and/or umbilical cord abnormalities were recorded using the same protocol for both groups and confirmed after birth.

RESULTS

IVF pregnancies had a significantly higher risk of low-lying placenta, placenta previa, bilobed placenta and velamentous cord insertion (VCI) compared with spontaneous pregnancies. In the heterologous subgroup there was a significant increased incidence of placenta accreta spectrum (PAS) disorders than in spontaneous pregnancies. All these anomalies were identified prenatally on ultrasound imaging and confirmed at birth.

DISCUSSION

IVF pregnancies in general and those resulting from donor oocyte in particular are at higher risk of placental and umbilical cord abnormalities compared to spontaneous pregnancies. These anomalies can be diagnosed accurately at the mid-trimester detailed fetal anomaly scan and our findings support the need for a targeted ultrasound screening of these anomalies in IVF pregnancies.

Searching for placenta percreta: a prospective cohort and systematic review of case reports

BACKGROUND

Placenta percreta is described as the most severe grade of placenta accreta spectrum and accounts for a quarter of all cases of placenta accreta spectrum reported in the literature.

OBJECTIVE

We investigated the hypothesis that placenta percreta, which has been described clinically as placental tissue invading through the full thickness of the uterus, is a heterogeneous category with most cases owing to primary or secondary uterine abnormality rather than an abnormally invasive form of placentation.

STUDY DESIGN

We have evaluated the agreement between the intraoperative findings using the International Federation of Gynecology and Obstetrics classification with the postoperative histopathology diagnosis in a prospective cohort of 101 consecutive singleton pregnancies presenting with a low-lying placenta or placenta previa, a history of at least 1 prior cesarean delivery and ultrasound signs suggestive of placenta accreta spectrum. Furthermore, a systematic literature review of case reports of placenta percreta, which included histopathologic findings and gross images, was performed.

RESULTS

Samples for histologic examination were available in 80 of 101 cases of the cohort, which were managed by hysterectomy or partial myometrial resection. Microscopic examination showed evidence of placenta accreta spectrum in 65 cases (creta, 9; increta, 56). Of 101 cases included in the cohort, 44 (43.5%) and 54 (53.5%) were graded as percreta by observer A and observer B, respectively. There was a moderate agreement between observers. Of note, 11 of 36 cases that showed no evidence of abnormal placental attachment at delivery and/or microscopic examination were classified as percreta by both observers. The systematic literature review identified 41 case reports of placenta percreta with microscopic images and presenting symptomatology, suggesting that most cases were the consequence of a uterine rupture. The microscopic descriptions were heterogeneous, and all descriptions demonstrated histology of placenta creta rather than percreta.

CONCLUSION

Our study supported the concept that placenta accreta is not an invasive disorder of placentation but the consequence of postoperative surgical remodeling or a preexisting uterine pathology and found no histologic evidence supporting the existence of a condition where the villous tissue penetrates the entire uterine wall, including the serosa and beyond.

Prospective evaluation of impact of post-Cesarean section uterine scarring in perinatal diagnosis of placenta accreta spectrum disorder

OBJECTIVE

Standardized ultrasound imaging and pathology protocols have recently been developed for the perinatal diagnosis of placenta accreta spectrum (PAS) disorders. The aim of this study was to evaluate prospectively the effectiveness of these standardized protocols in the prenatal diagnosis and postnatal examination of women presenting with a low-lying placenta or placenta previa and a history of multiple Cesarean deliveries (CDs).

METHODS

This was a prospective cohort study of 84 consecutive women with a history of two or more prior CDs presenting with a singleton pregnancy and low-lying placenta/placenta previa at 32-37 weeks' gestation, who were referred for perinatal care and management between 15 January 2019 and 15 December 2020. All women were investigated using the standardized description of ultrasound signs of PAS proposed by the European Working Group on abnormally invasive placenta. In all cases, the ultrasound features were compared with intraoperative and histopathological findings. Areas of abnormal placental attachment were identified during the immediate postoperative gross examination and sampled for histological examination. The data of a subgroup of 32 women diagnosed antenatally as non-PAS who had complete placental separation at birth were compared with those of 39 cases diagnosed antenatally as having PAS disorder that was confirmed by histopathology at delivery.

RESULTS

Of the 84 women included in the study, 42 (50.0%) were diagnosed prenatally as PAS and the remaining 42 (50.0%) as non-PAS on ultrasound examination. Intraoperatively, 66 (78.6%) women presented with a large or extended area of dehiscence and 52 (61.9%) with a dense tangled bed of vessels or multiple vessels running laterally and craniocaudally in the uterine serosa. A loss of clear zone was recorded on grayscale ultrasound imaging in all 84 cases, while there was no case with bladder-wall interruption or with a focal exophytic mass. Myometrial thinning (< 1 mm) in at least one area of the anterior uterine wall was found in 41 (97.6%) of the 42 cases diagnosed as non-PAS on ultrasound and 37 (88.1%) of the 42 diagnosed antenatally as PAS. Histological samples were available for all 48 hysterectomy specimens with abnormal placental attachment and for the three cases managed conservatively with focal myometrial resection and uterine reconstruction. Villous tissue was found directly attached to the superficial myometrium (placenta creta) in six of these cases and both creta villous tissue and deeply implanted villous tissue within the uterine wall (placenta increta) were found in the remaining 45 cases. There was no evidence of percreta placentation on histology in any of the PAS cases. Comparison of the main antenatal ultrasound signs and perioperative macroscopic findings between the two subgroups correctly diagnosed antenatally (32 non-PAS and 39 PAS) showed no significant difference with respect to the distribution of myometrial thinning and the presence of a placental bulge on ultrasound and of anterior uterine wall dehiscence intraoperatively. Compared with the non-PAS subgroup, the PAS subgroup showed significantly higher placental lacunae grade (P < 0.001) and more often hypervascularity of the uterovesical/subplacental area (P < 0.001), presence of bridging vessels (P = 0.027) and presence of lacunae feeder vessels (P < 0.001) on ultrasound examination, and increased vascularization of the anterior uterine wall intraoperatively (P < 0.001).

CONCLUSIONS

Remodeling of the lower uterine segment following CD scarring leads to structural abnormalities of the uterine contour on both ultrasound examination and intraoperatively, independently of the presence of accreta villous tissue on microscopic examination. These anatomical changes are often reported as diagnostic of placenta percreta, including cases with no histological evidence of PAS. Guided histological examination could improve the overall diagnosis of PAS and is essential to obtain evidence-based epidemiologic data. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prospective Evaluation of the Ultrasound Signs Proposed for the Description of Uterine Niche in Nonpregnant Women

OBJECTIVES

To evaluate the new ultrasound-based signs for the diagnosis of post-cesarean section uterine niche in nonpregnant women.

METHODS

We investigated prospectively a cohort of 160 consecutive women with one previous term cesarean delivery (CD) between December 2019 and 2020. All women were separated into two subgroups according to different stages of labor at the time of their CD: subgroup A (n = 109; 68.1%) for elective CD and CD performed in latent labor at a cervical dilatation (≤4 cm) and subgroup B (n = 51; 31.9%); for CD performed during the active stage of labor (>4 cm).

RESULTS

Overall, the incidence of a uterine niche was significantly (P < .001) higher in women who had an elective (20/45; 44.4%) compared with those who had an emergent (21/115; 18.3%) CD. Compared with subgroup B, subgroup A presented with a significantly (P = .012) higher incidence of uterine niche located above the vesicovaginal fold and with a significantly (P = .0002) lower proportion of cesarean scar positioned below the vesicovaginal fold. There was a significantly (P < .001) higher proportion of women with a residual myometrial thickness (RMT) > 3 mm in subgroup A than in subgroup B and a significant negative relationship was found between the RMT and the cervical dilatation at CD (r = -0.22; P = .008).

CONCLUSIONS

Sonographic cesarean section scar assessment indicates that the type of CD and the stage of labor at which the hysterotomy is performed have an impact on the location of the scar and the scarification process including the niche formation and RMT.

New insights into the etiopathology of placenta accreta spectrum

Placenta accreta has been described as a spectrum of abnormal attachment of villous tissue to the uterine wall, ranging from superficial attachment to the inner myometrium without interposing decidua to transmural invasion through the entire uterine wall and beyond. These descriptions have prevailed for more than 50 years and form the basis for the diagnosis and grading of accreta placentation. Accreta placentation is essentially the consequence of uterine remodeling after surgery, primarily after cesarean delivery. Large cesarean scar defects in the lower uterine segment are associated with failure of normal decidualization and loss of the subdecidual myometrium. These changes allow the placental anchoring villi to implant, and extravillous trophoblast cells to migrate, close to the serosal surface of the uterus. These microscopic features are central to the misconception that the accreta placental villous tissue is excessively invasive and have led to much confusion and heterogeneity in clinical data. Progressive recruitment of large arteries in the uterine wall, that is, helicine, arcuate, and/or radial arteries, results in high-velocity maternal blood entering the intervillous space from the first trimester of pregnancy and subsequent formation of placental lacunae. Recently, guided sampling of accreta areas at delivery has enabled accurate correlation of prenatal imaging data with intraoperative features and histopathologic findings. In more than 70% of samples, there were thick fibrinoid depositions between the tip of most anchoring villi and the underlying uterine wall and around all deeply implanted villi. The distortion of the uteroplacental interface by these dense depositions and the loss of the normal plane of separation are the main factors leading to abnormal placental attachment. These data challenged the classical concept that placenta accreta is simply owing to villous tissue sitting atop the superficial myometrium without interposed decidua. Moreover, there is no evidence in accreta placentation that the extravillous trophoblast is abnormally invasive or that villous tissue can cross the uterine serosa into the pelvis. It is the size of the scar defect, the amount of placental tissue developing inside the scar, and the residual myometrial thickness in the scar area that determine the distance between the placental basal plate and the uterine serosa and thus the risk of accreta placentation.

Development of the utero-placental circulation in cesarean scar pregnancies: a case-control study

BACKGROUND

Cesarean scar pregnancies carry a high risk of pregnancy complications including placenta previa with antepartum hemorrhage, placenta accreta spectrum, and uterine rupture.

OBJECTIVE

To evaluate the development of utero-placental circulation in the first half of pregnancy in ongoing cesarean scar pregnancies and compare it with pregnancies implanted in the lower uterine segment above a previous cesarean delivery scar with no evidence of placenta accreta spectrum at delivery STUDY DESIGN: This was a retrospective case-control study conducted in 2 tertiary referral centers. The study group included 27 women who were diagnosed with a live cesarean scar pregnancy in the first trimester of pregnancy and who elected to conservative management. The control group included 27 women diagnosed with an anterior low-lying placenta or placenta previa at 19 to 22 weeks of gestation who had first and early second trimester ultrasound examinations. In both groups, the first ultrasound examination was carried out at 6 to 10 weeks to establish the pregnancy location, viability, and to confirm the gestational age. The utero-placental and intraplacental vasculatures were examined using color Doppler imaging and were described semiquantitatively using a score of 1 to 4. The remaining myometrial thickness was recorded in the study group, whereas the ultrasound features of a previous cesarean delivery scar including the presence of a niche were noted in the controls. Both the cesarean scar pregnancies and the controls had ultrasound examinations at 11 to 14 and 19 to 22 weeks of gestation.

RESULTS

The mean color Doppler imaging vascularity score in the ultrasound examination at 6 to 10 weeks was significantly (P<.001) higher in the cesarean scar pregnancy group than in the controls. High vascularity scores of 3 and 4 were recorded in 20 of 27 (74%) cases of the cesarean scar pregnancy group. There was no vascularity score of 4, and only 3 of 27 (11%) controls had a vascularity score of 3. In 15 of the 27 (55.6%) cesarean scar pregnancies, the residual myometrial thickness was <2 mm. In the ultrasound examination at 11 to 14 weeks, there was no significant difference between the groups in the number of cases with an increased subplacental vascularity. However, 12 cesarean scar pregnancies (44%) presented with 1 or more placental lacunae whereas there was no case with lacunae in the controls. Of the 18 cesarean scar pregnancies that progressed into the third trimester, 10 of them were diagnosed with placenta previa accreta at birth, including 4 creta and 6 increta. In the 19 to 22 weeks ultrasound examination, 8 of the 10 placenta accreta spectrum patients presented with subplacental hypervascularity, out of which 6 showed placental lacunae.

CONCLUSION

The vascular changes in the utero-placental and intervillous circulations in cesarean scar pregnancies are due to the loss of the normal uterine structure in the scar area and the development of placental tissue in proximity of large diameter arteries of the outer uterine wall. The intensity of these vascular changes, the development of placenta accreta spectrum, and the risk of uterine rupture are probably related to the residual myometrial thickness of the scar defect at the start of pregnancy. A better understanding of the pathophysiology of the utero-placental vascular changes associated with cesarean scar pregnancies should help in identifying those cases that may develop major complications. It will contribute to providing counseling for women about the risks associated with different management strategies.

Failure of placental detachment in accreta placentation is associated with excessive fibrinoid deposition at the utero-placental interface

BACKGROUND

The main histopathologic diagnostic criteria for the diagnosis of placenta accreta for more than 80 years has been the finding of a direct attachment of the villous tissue to the superficial myometrium or adjacent to myometrial fibers without interposing decidua. There have been very few detailed histopathologic studies in pregnancies complicated by placenta accreta spectrum disorders and our understanding of the pathophysiology of the condition remains limited.

OBJECTIVE

To prospectively evaluate the microscopic changes used in grading and to identify changes that might explain the abnormal placental tissue attachment.

STUDY DESIGN

A total of 40 consecutive cesarean delivery hysterectomy specimens for placenta previa accreta at 32 to 37 weeks of gestation with at least 1 histologic slide showing deeply implanted villi were analyzed. Prenatal ultrasound examination included placental location, myometrial thickness, subplacental vascularity and lacunae. Macroscopic changes of the lower segment were recorded during surgery and areas of abnormal placental adherence were sampled for histology. In addition, 7 hysterectomy specimens with placenta in-situ from the Boyd Collection at 20.5 to 32.5 weeks were used as controls.

RESULTS

All 40 patients had a history of at least 2 previous cesarean deliveries and presented with a mainly anterior placenta previa. Of note, 37 (92.5%) cases presented with increased subplacental vascularity, 31 (77.5%) cases with myometrial thinning and all with lacunae. Furthermore, 20 (50%) cases presented with subplacental hypervascularity, lacunae score of >3, and lacunae feeder vessels. Intraoperative findings included anterior lower segment wall increased vascularization in 36 (90.0%) cases and extended area of dehiscence in 18 (45.0%) cases. Immediate gross examination of hysterectomy specimens showed an abnormally attached areas involving up to 30% of the basal plate, starting at <2 cm from the dehiscence area in all cases. Histologic examination found deeply implanted villi in 86 (53.8%) samples with only 17 (10.6%) samples presenting with villous tissue reaching at least half the uterine wall thickness. There were no villi crossing the entire thickness of the uterine wall. There was microscopic evidence of myometrial scarification in all cases. Dense fibrinoid deposits, 0.5 to 2 mm thick, were found at the utero-placental interface in 119 (74.4%) of the 160 samples between the anchoring villi and the underlying uterine wall at the accreta areas and around all deeply implanted villi. In the control group, the Nitabuch stria and basal plate became discontinuous with advancing gestation and there was no evidence of fibrinoid deposition at these sites.

CONCLUSION

Samples from accreta areas at delivery present with a thick fibrinoid deposition at the utero-placental interface on microscopic examination independently of deeply implanted villous tissue in the sample. These changes are associated with distortion of the Nitabuch membrane and might explain the loss of parts of the physiological site of detachment of the placenta from the uterine wall in placenta accreta spectrum. These findings indicate that accreta placentation is more than direct attachment of the villous tissue to the superficial myometrium and support the concept that accreta villous tissue is not truly invasive.

Global inequality in sub-fertility treatment needs safer, cost effective, evidence-based and economically viable choices for patients and stakeholders

The global increase in subfertility diagnosis and treatments and the rise of private equity investors concentrating on high profits based on in vitro fertilisation (IVF) treatments raise profound societal and economic questions for stakeholders and patients. The question remains as to whose benefits will ultimately be greater when promoting high margins treatment options resulting from cross-border mergers and acquisitions of IVF clinics.This paper covers wide-ranging issues from the erroneously constructed UK National Institute for Health and Care Excellence’s (NICE) guidelines on treatment choices, the cost-effectiveness of treatments, the promotion of IVF, and add-ons where evidence remains minimal, the commercial size of the fertility industry. Investment in improving intrauterine insemination (IUI) success rates has understandably been avoided for its short-term impact on the IVF industry. However, IUI efficiency would cut across many of the global subfertility treatment economic and access problems while allowing stakeholder, feepaying, and patients financial savings will likely allow for more funded IVF cycles in acutely deserving cases. The recommendations will help expand choices for globally economically challenged patients’ and services while enhancing an ethical and moral dimension towards fertility treatment choices for patients and stakeholders.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Risk prediction of major haemorrhage with surgical treatment of live cesarean scar pregnancies

OBJECTIVE

To evaluate the association between demographic and ultrasound variables and major intra-operative blood loss during surgical transcervical evacuation of live caesarean scar pregnancies.

STUDY DESIGN

This was a retrospective cohort study conducted in a tertiary referral center between 2008 and 2019. We included all women diagnosed with a live caesarean scar ectopic pregnancy who chose to have surgical management in the study center. A preoperative ultrasound was performed in each patient. All women underwent transcervical suction curettage under ultrasound guidance. Our primary outcome was the rate of postoperative blood transfusion. The secondary outcomes were estimated intra-operative blood loss (ml), rate of retained products of conception, need for repeat surgery, need for uterine artery embolization and hysterectomy rate. Descriptive statistics were used to describe the variables. Univariate and multivariable logistic regression models were constructed using the relevant covariates to identify the significant predictors for severe blood loss.

RESULTS

During the study period, 80 women were diagnosed with a live caesarean scar pregnancy, of whom 62 (78%) opted for surgical management at our center. The median crown-rump length was 9.3 mm (range 1.4-85.7). Median blood loss at the time of surgery was 100 ml (range, 10-2300), and six women (10%; 95%CI 3.6-20) required blood transfusion. Crown-rump length and presence of placental lacunae were significant predictive factors for the need for blood transfusion and blood loss > 500 ml at univariate analysis (p < .01); on multivariate analysis, only crown-rump length was a significant predictor for need for blood transfusion (OR = 1.072; 95% CI 1.02-1.11). Blood transfusion was required in 6/18 (33%) cases with the crown-rump length ≥ 23 mm (≥9⁺⁰ weeks of gestation), but in none of 44 women presenting with a crown-rump length < 23 mm (p < .01).

CONCLUSION

The risk of severe intraoperative bleeding and need for blood transfusion during or after surgical evacuation of live caesarean scar pregnancies increases with gestational age and is higher in the presence of placental lacunae. One third of women presenting at ≥ 9 weeks of gestation required blood transfusion and their treatment should be ideally arranged in specialized tertiary centers.

RNA-Seq reveals changes in human placental metabolism, transport and endocrinology across the first-second trimester transition

The human placenta is exposed to major environmental changes towards the end of the first trimester associated with full onset of the maternal arterial placental circulation. Changes include a switch from histotrophic to hemotrophic nutrition, and a threefold rise in the intraplacental oxygen concentration. We evaluated their impact on trophoblast development and function using RNA-sequencing (RNA-Seq) and DNA-methylation analyses performed on the same chorionic villous samples at 7-8 (n=8) and 13-14 (n=6) weeks of gestation. Reads were adjusted for fetal sex. Most DEGs were associated with protein processing in the endoplasmic reticulum (ER), hormone secretion, transport, extracellular matrix, vasculogenesis, and reactive oxygen species metabolism. Transcripts higher in the first trimester were associated with synthesis and ER processing of peptide hormones, and glycolytic pathways. Transcripts encoding proteins mediating transport of oxygen, lipids, protein, glucose, and ions were significantly increased in the second trimester. The motifs of CBX3 and BCL6 were significantly overrepresented, indicating the involvement of these transcription factor networks in the regulation of trophoblast migration, proliferation and fusion. These findings are consistent with a high level of cell proliferation and hormone secretion by the early placenta to secure implantation in a physiological low-oxygen environment.

Impact of the COVID-19 Pandemic on Excess Perinatal Mortality and Morbidity in Israel

OBJECTIVE

The 2020 COVID-19 pandemic has been associated with excess mortality and morbidity in adults and teenagers over 14 years of age, but there is still limited evidence on the direct and indirect impact of the pandemic on pregnancy. We aimed to evaluate the effect of the first wave of the COVID-19 pandemic on obstetrical emergency attendance in a low-risk population and the corresponding perinatal outcomes.

STUDY DESIGN

This is a single center retrospective cohort study of all singleton births between February 21 and April 30. Prenatal emergency labor ward admission numbers and obstetric outcomes during the peak of the first COVID-19 pandemic of 2020 in Israel were compared with the combined corresponding periods for the years 2017 to 2019.

RESULTS

During the 2020 COVID-19 pandemic, the mean number of prenatal emergency labor ward admissions was lower, both by daily count and per woman, in comparison to the combined matching periods in 2017, 2018, and 2019 (48.6 ± 12.2 vs. 57.8 ± 14.4, p < 0.0001 and 1.74 ± 1.1 vs. 1.92 ± 1.2, p < 0.0001, respectively). A significantly (p = 0.0370) higher rate of stillbirth was noted in the study group (0.4%) compared with the control group (0.1%). All study group patients were negative for COVID-19. Gestational age at delivery, rates of premature delivery at <28, 34, and 37 weeks, pregnancy complications, postdate delivery at >40 and 41 weeks, mode of delivery, and numbers of emergency cesarean deliveries were similar in both groups. There was no difference in the intrapartum fetal death rate between the groups.

CONCLUSION

The COVID-19 pandemic stay-at-home policy combined with patient fear of contracting the disease in hospital could explain the associated higher rate of stillbirth. This collateral perinatal damage follows a decreased in prenatal emergency labor ward admissions during the first wave of COVID-19 in Israel.

KEY POINTS

· Less obstetrical ER attendance is observed during the pandemic.. · There is a parallel increase in stillbirth rate.. · Stillbirth cases tested negative for COVID-19.. · Lockdown and pandemic panic are possible causes..

Predictive value of presence of amniotic sac without visible embryonic heartbeat in diagnosis of early embryonic demise

OBJECTIVES

To assess the diagnostic value and impact on management of visualizing on ultrasound an amniotic sac without a live embryo (amniotic sac sign). We also examined the potential effect on the number of follow-up visits in early pregnancy units of incorporating this sign into current diagnostic algorithms.

METHODS

This was a prospective cohort study of all pregnant women who attended a single specialist early pregnancy unit from July 2017 to November 2018 with symptoms of pain and/or bleeding, or with a history of ectopic pregnancy or miscarriage, at < 14 weeks' gestation. Detailed initial ultrasound findings were documented, including whether an amniotic sac was present in a normally sited intrauterine pregnancy with absence of a live embryo. Women were followed up until a conclusive diagnosis was made.

RESULTS

The study included 6012 women who attended our unit with early pregnancy complications during the study period. A conclusive diagnosis was reached on the initial scan in 4221 (70.2%), whilst 1135 (18.9%) women had a pregnancy of uncertain viability and 656 (10.9%) had a pregnancy of unknown location (PUL). All women with a pregnancy of uncertain viability required follow-up ultrasound scans to differentiate between a live pregnancy and early embryonic demise. An amniotic sac in the absence of a live embryo was found in 174/1135 (15.3%) women with a pregnancy of uncertain viability at the initial ultrasound scan. The diagnosis of early embryonic demise was confirmed in all 134 of these women who attended their follow-up scans. The presence of an amniotic sac without a live embryo at the initial visit had a specificity of 100% (95% CI, 98.53-100.00%) and positive predictive value of 100% (95% CI, 97.2-100.0%) for the diagnosis of early pregnancy failure. A total of 1403/6012 (23.3%) women were asked to attend for a follow-up ultrasound scan to resolve diagnostic uncertainties, including 268/656 (40.9%) women with a PUL. The majority of follow-up scans needed to reach a conclusive diagnosis were in women with a pregnancy of uncertain viability (1135/1403 (80.9%)). By using the presence of the amniotic sac sign to diagnose early pregnancy failure at the first visit, the number of follow-up scans for pregnancies of uncertain viability would be reduced by 14.4%, which accounted for 11% of all follow-up scans during the study period.

CONCLUSIONS

The finding on ultrasound of an amniotic sac without a live embryo (amniotic sac sign) is a reliable marker of early pregnancy failure and could reduce the number of follow-up scans by 11% in cases of diagnostic uncertainty. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

HYPOXIA AND REPRODUCTIVE HEALTH: Oxygen and development of the human placenta

Development of the human placenta takes place in contrasting oxygen concentrations at different stages of gestation, from ~20 mmHg during the first trimester rising to ~60 mmHg at the start of the second trimester before gradually declining to ~40 mmHg at term. In view of these changes, the early placenta has been described as 'hypoxic'. However, placental metabolism is heavily glycolytic, supported by the rich supply of glucose from the endometrial glands, and there is no evidence of energy compromise. On the contrary, the trophoblast is highly proliferative, with the physiological low-oxygen environment promoting maintenance of stemness in progenitor populations. These conditions favour the formation of the cytotrophoblastic shell that encapsulates the conceptus and interfaces with the endometrium. Extravillous trophoblast cells on the outer surface of the shell undergo an epithelial-mesenchymal transition and acquire invasive potential. Experimental evidence suggests that these changes may be mediated by the higher oxygen concentration present within the placental bed. Interpreting in vitro data is often difficult, however, due to the use of non-physiological oxygen concentrations and trophoblast-like cell lines or explant models. Trophoblast is more vulnerable to hyperoxia or fluctuating levels of oxygen than to hypoxia, and some degree of placental oxidative stress likely occurs in all pregnancies towards term. In complications of pregnancy, such as early-onset pre-eclampsia, malperfusion generates high levels of oxidative stress, causing release of factors that precipitate the maternal syndrome. Further experiments are required using genuine trophoblast progenitor cells and physiological concentrations to fully elucidate the pathways by which oxygen regulates placental development.

Placentation in the Human and Higher Primates

Placentation in humans is precocious and highly invasive compared to other mammals. Implantation is interstitial, with the conceptus becoming completely embedded within the endometrium towards the end of the second week post-fertilization. Villi initially form over the entire surface of the chorionic sac, stimulated by histotrophic secretions from the endometrial glands. The secondary yolk sac never makes contact with the chorion, and a choriovitelline placenta is never established. However, recent morphological and transcriptomic analyses suggest that the yolk sac plays an important role in the uptake of nutrients from the coelomic fluid. Measurements performed in vivo demonstrate that early development takes place in a physiological, low-oxygen environment that protects against teratogenic free radicals and maintains stem cells in a multipotent state. The maternal arterial circulation to the placenta is only fully established around 10-12 weeks of gestation. By then, villi have regressed over the superficial, abembryonic pole, leaving the definitive discoid placenta, which is of the villous, hemochorial type. Remodeling of the maternal spiral arteries is essential to ensure a high-volume but low-velocity inflow into the mature placenta. Extravillous trophoblast cells migrate from anchoring villi and surround the arteries. Their interactions with maternal immune cells release cytokines and proteases that are key to remodeling, and a successful pregnancy.