Placenta accreta spectrum disorder at single-cell resolution: a loss of boundary limits in the decidua and endothelium.

BACKGROUND: Placenta accreta spectrum disorders are associated with severe maternal morbidity and mortality. Placenta accreta spectrum disorders involve excessive adherence of the placenta preventing separation at birth. Traditionally, this condition has been attributed to excessive trophoblast invasion; however, an alternative view is a fundamental defect in decidual biology. OBJECTIVE: This study aimed to gain insights into the understanding of placenta accreta spectrum disorder by using single-cell and spatially resolved transcriptomics to characterize cellular heterogeneity at the maternal-fetal interface in placenta accreta spectrum disorders. STUDY DESIGN: To assess cellular heterogeneity and the function of cell types, single-cell RNA sequencing and spatially resolved transcriptomics were used. A total of 12 placentas were included, 6 placentas with placenta accreta spectrum disorder and 6 controls. For each placenta with placenta accreta spectrum disorder, multiple biopsies were taken at the following sites: placenta accreta spectrum adherent and nonadherent sites in the same placenta. Of note, 2 platforms were used to generate libraries: the 10× Chromium and NanoString GeoMX Digital Spatial Profiler for single-cell and spatially resolved transcriptomes, respectively. Differential gene expression analysis was performed using a suite of bioinformatic tools (Seurat and GeoMxTools R packages). Correction for multiple testing was performed using Clipper. In situ hybridization was performed with RNAscope, and immunohistochemistry was used to assess protein expression. RESULTS: In creating a placenta accreta cell atlas, there were dramatic difference in the transcriptional profile by site of biopsy between placenta accreta spectrum and controls. Most of the differences were noted at the site of adherence; however, differences existed within the placenta between the adherent and nonadherent site of the same placenta in placenta accreta. Among all cell types, the endothelial-stromal populations exhibited the greatest difference in gene expression, driven by changes in collagen genes, namely collagen type III alpha 1 chain (COL3A1), growth factors, epidermal growth factor-like protein 6 (EGFL6), and hepatocyte growth factor (HGF), and angiogenesis-related genes, namely delta-like noncanonical Notch ligand 1 (DLK1) and platelet endothelial cell adhesion molecule-1 (PECAM1). Intraplacental tropism (adherent versus non-adherent sites in the same placenta) was driven by differences in endothelial-stromal cells with notable differences in bone morphogenic protein 5 (BMP5) and osteopontin (SPP1) in the adherent vs nonadherent site of placenta accreta spectrum. CONCLUSION: Placenta accreta spectrum disorders were characterized at single-cell resolution to gain insight into the pathophysiology of the disease. An atlas of the placenta at single cell resolution in accreta allows for understanding in the biology of the intimate maternal and fetal interaction. The contributions of stromal and endothelial cells were demonstrated through alterations in the extracellular matrix, growth factors, and angiogenesis. Transcriptional and protein changes in the stroma of placenta accreta spectrum shift the etiologic explanation away from "invasive trophoblast" to "loss of boundary limits" in the decidua. Gene targets identified in this study may be used to refine diagnostic assays in early pregnancy, track disease progression over time, and inform therapeutic discoveries.

Evaluation of Cesarean section scar using saline contrast sonohysterography in women with previous Cesarean scar pregnancy.

OBJECTIVE: To evaluate Cesarean scar defects using saline contrast sonohysterography (SCSH) in women with a history of Cesarean scar pregnancy (CSP). METHODS: A cohort of 38 non-pregnant women with a history of CSP treated with combined local and systemic methotrexate was investigated prospectively by SCSH. For the purpose of analysis, they were classified, according to the modified Delphi consensus criteria for CSP in early gestation, into three subgroups based on the depth of the gestational sac herniation in the midsagittal plane. Subgroup A included eight (21.1%) cases, in which the largest part of the gestational sac protruded towards the uterine cavity; Subgroup B included 20 (52.6%) cases, in which the largest part of the gestational sac was embedded in the myometrium; and Subgroup C included 10 (26.3%) cases, in which the gestational sac was located partially outside the outer contour of the cervix or uterus. RESULTS: SCSH revealed that all women in Subgroup C had a uterine niche. The median niche length (P = 0.006) and depth (P = 0.015) were significantly greater in Subgroup C than in Subgroups A or B. The median residual myometrial thickness (RMT) was significantly lower in Subgroup C than in Subgroups A or B (P = 0.006). CONCLUSIONS: Women with prior CSP who had a gestational sac protruding beyond the serosal line had a significantly greater niche length and depth, and lower RMT. This knowledge may guide individualized risk counseling. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

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.

Effectiveness of an articulating laparoscopic needle holder for cesarean scar defect repair.

AIM: To evaluate the efficacy of an articulating laparoscopic needle holder in laparoscopic surgery for cesarean scar defect. METHODS: We performed a retrospective case-control study at the Shiga University of Medical Science. Patients who underwent laparoscopic uterine scar repair were divided into an articulating laparoscopic needle holder (ArtiSential®) group and a rigid needle holder (conventional) group to compare the suture and total operative times. Uterine myometrial suturing involves a double-layer interrupted suture, including a modified Gambee suture for the first layer. We measured the residual myometrial thickness using magnetic resonance imaging preoperatively and at 3 months postoperatively. RESULTS: Both groups comprised 10 patients each. The time per stitch for the first and second layers was significantly shorter in the ArtiSential group than in the conventional group (median 208 s vs. 403 s, p < 0.0001 and median 17 s vs. 29 s; p < 0.0001, respectively). The total operating time was significantly shorter in the ArtiSential group (mean 188 min vs. 240 min, p = 0.0015). The postoperative residual myometrial thickness (mean 9.1 mm in the ArtiSential group and 9.6 mm in the conventional group) was significantly higher than the preoperative residual myometrial thickness (mean 1.6 mm in the ArtiSential group and 1.6 mm in the conventional group) (p < 0.0001 in both groups). CONCLUSIONS: An articulating needle holder is useful in laparoscopic surgery for cesarean scar defect, especially when a modified Gambee suture is required.

Ultrasound evaluation of scar thickness for prediction of uterine dehiscence in term women with previous caesarean sections.

Objective: To determine the role of ultrasound in evaluation of scar thickness for prediction of uterine dehiscence. Method: This retrospective cross-sectional study was conducted in the Radiology department of Aga Khan University Hospital from 1st July to 31st December 2021 after approval from the University Ethic Committee. In this study pregnant women 18 to 40 years with a live singleton fetus with vertex presentation, at term, with history of prior caesarean section and availability of medical record were included. Using a curvilinear ultrasound transducer with optimally distended urinary bladder, the myometrial thickness was measured in the sagittal plane. The intraoperative visual findings of the lower uterine segment outcome at the time of C-section were recorded and categorized into two groups i.e., with and without dehiscence for statistical analysis. Results: A total of 126 women were included. The mean age of the study participants was 29.8±4.1. The median gestational age was 35 (34-37) weeks. The highest AUC 0.58 was recorded for the scar thickness of ≤2.5mm with a sensitivity, specificity, PPV and NPV of 80.9%, 36.4%, 36.3% and 80.8% respectively. Similarly, the AUC for the scar thickness of ≤2mm was 0.55 with a sensitivity, specificity, PPV and NPV of 93%, 18.2%, 18.2% and 93% respectively. Conclusion: Transabdominal Sonography is a safe technique to determine the LUS thickness during antenatal ultrasound at term. A cutoff value of ≤2mm showed a high sensitivity and negative predictive value of 93% for evaluating the risk of uterine dehiscence.

The association between uterine scar defect (niche) and the presence of symptoms.

RESEARCH QUESTION: Is there association between the presence of a uterine niche and the presence of symptoms? DESIGN: This cross-sectional study was conducted at a single tertiary medical centre. All women who underwent Caesarean section from January 2017 to June 2020 were invited to the gynaecological clinics, and requested to complete a questionnaire regarding symptoms related to the presence of a niche (heavy menstrual bleeding, intermenstrual spotting, pelvic pain, infertility). Transvaginal two-dimensional ultrasonography was performed to assess the uterus and uterine scar characteristics. The primary outcome was defined as the presence of a uterine niche, evaluated by length, depth, residual myometrial thickness (RMT) and ratio between the residual myometrial thickness (RMT) and adjacent myometrial thickness (AMT). RESULTS: Of 524 women who were eligible and scheduled for evaluation, 282 (54%) completed the follow-up; 173 (61.3%) were symptomatic and 109 (38.6%) asymptomatic. Niche measurements, including RMT/AMT ratio, were comparable between the groups. In a sub-analysis of each symptom, heavy menstrual bleeding and intermenstrual spotting were associated with reduced RMT (P = 0.02 and P = 0.04, respectively) compared with women with normal menstrual bleeding. An RMT less than 2.5 mm was significantly more prevalent in women reporting heavy menstrual bleeding (11 [25.6%] versus 27 [11.3%]; P = 0.01] and new infertility (7 [16.3%] versus 6 [2.5%]; P = 0.001]. In logistic regression analysis, infertility was the only symptom associated with an RMT less than 2.5 mm (B = 1.9; P = 0.002). CONCLUSIONS: A reduced RMT was found to be associated with heavy menstrual bleeding and intermenstrual spotting, while values below 2.5 mm were also associated with infertility.

Conservative management of complete fetal expulsion into the abdominal cavity after silent uterine rupture - case report.

BACKGROUND: Clinically silent uterine rupture with complete fetal expulsion into the abdominal cavity is an extremely rare complication. Diagnosis can be difficult and the risk to the mother and fetus is high. Conservative management has been described only in a few cases of partial expulsion of the fetus so far. CASE PRESENTATION: We present a case of 43-year-old tercigravida with a history of previous laparotomic myomectomy and subsequent cesarean section. The subsequent pregnancy was complicated by uterine wall loosening and rupture at the site of the previous uterine scar after myomectomy and complete fetal expulsion into the abdominal cavity. The diagnosis was made at 24 + 6 weeks of gestation. Considering the absence of clinical symptomatology and the good condition of the fetus, a conservative approach was chosen with intensive monitoring of the maternal and fetal conditions. The pregnancy ended by elective cesarean section and hysterectomy at 28 + 0 weeks of gestation. The postpartum course was uneventful and the newborn was discharged to home care 63 days after delivery. CONCLUSIONS: Fetal expulsion into the abdominal cavity after silent uterine rupture of the scarred uterus may be accompanied by minimal symptomatology making early diagnosis difficult. This rare complication must be considered in the differential diagnosis in women after major uterine surgery. In selected cases and under conditions of intensive maternal and fetal monitoring, conservative management may be chosen to reduce the risks associated with prematurity.

Ultrasound evaluation of uterine scar thickness after open fetal surgery for myelomeningocele.

PURPOSE: This study aimed to analyse the evolution of uterine scar thickness after open fetal surgery for myelomeningocele (MMC) by ultrasonography, and to establish a cut-off point for uterine scar thickness associated with high-risk of uterine rupture. METHODS: A prospective longitudinal study was conducted with 77 pregnant women who underwent open fetal surgery for MMC between 24 and 27 weeks of gestation. After fetal surgery, ultrasound follow-up was performed once a week, and the scar on the uterine wall was evaluated and its thickness was measured by transabdominal ultrasound. At least five measurements of the uterine scar thickness were performed during pregnancy. A receiver operating characteristics (ROC) curve was constructed to obtain a cut-off point for the thickness of the scar capable of detecting the absence of thinning. Kaplan-Meier curves were constructed to evaluate the probability of thinning during pregnancy follow-up. RESULTS: The mean ± standard deviation of maternal age (years), gestational age at surgery (weeks), gestational age at delivery (weeks), and birth weight (g) were 30.6 ± 4.5, 26.1 ± 0.8, 34.3 ± 1.2 and 2287.4 ± 334.4, respectively. Thinning was observed in 23 patients (29.9%). Pregnant women with no thinning had an average of 17.1 ± 5.2 min longer surgery time than pregnant women with thinning. A decrease of 1.0 mm in the thickness of the uterine scar was associated with an increased likelihood of thinning by 1.81-fold (95% confidence interval [CI]: 1.32-2.47; p < 0.001). The area below the ROC curve was 0.899 (95% CI: 0.806-0.954; p < 0.001), and the cut-off point was ≤ 3.0 mm, which simultaneously presented greater sensitivity and specificity. After 63 days of surgery, the probability of uterine scarring was 50% (95% CI: 58-69). CONCLUSION: A cut-off point of ≤ 3.0 mm in the thickness of the uterine scar after open fetal surgery for MMC may be used during ultrasonography monitoring for decision-making regarding the risk of uterine rupture and indication of caesarean section.

Measurement of Lower Uterine Segment Thickness to Detect Uterine Scar Defect: Comparison of Transabdominal and Transvaginal Ultrasound.

OBJECTIVES: Lower uterine segment (LUS) thickness measurement using transabdominal ultrasound (TA-US), transvaginal ultrasound (TV-US), or the combination of both methods can detect scar defect in women with prior cesarean. We aimed to compare the sensitivity of three approaches. METHODS: Women with prior cesarean underwent LUS thickness measurement at 34-38 weeks' gestation. Among those who underwent repeat cesarean before labor, we compared the accuracy of TA-US, TV-US, and the thinner of the two measurements (the "combined measurement") for uterine scar dehiscence using the area under the curve (AUC) of receiver operating curves with their 95% confidence intervals (CI). We calculated the sensitivity and specificity of the three approaches using a cut-off of 2.3 mm based on prior literature. RESULTS: We included 747 participants. The mean LUS thickness was greater with TA-US (3.8 ± 1.6 mm) compared with TV-US (3.5 ± 1.9 mm) or the combined measurement (3.2 ± 1.5 mm; P < .001). The AUC was 78% (95% CI: 69%-87%), 85% (95% CI: 79%-91%), and 88% (95% CI: 82%-93%), respectively (all with P < .001). The AUC difference between TA-US and the combined measurement was not significant (P = .057). A LUS below 2.3 mm would have predicted 9 (45%) of the 20 cases of uterine scar dehiscence using TA-US, 17 (85%) using TV-US, and 18 (90%) using the combined measurement (P < .01). CONCLUSION: The choice of ultrasound approach influences the measurement of the LUS thickness. The combination of the TA-US and TV-US seems to be superior for the detection of uterine dehiscence.

Outcomes of Cesarean Scar Pregnancies in Early Gestation According to the New Delphi Consensus Criteria.

OBJECTIVES: Clinical evaluation of the new Delphi consensus definition of cesarean scar pregnancy (CSP) in early gestation. METHODS: A retrospective cohort of 36 women diagnosed with CSP and treated with combined local and systemic methotrexate (MTX) between 2008 and 2021. The CSPs were classified according to the new Delphi consensus criteria into three subgroups based on the depth of the gestational sac herniation in the sagittal plane. Subgroup A included 8 (22.2%) cases in which the largest part of the gestational sac protruded toward the uterine cavity. Subgroup B included 22 (61.1%) cases in which the largest part of the gestational sac was embedded in the myometrium, and subgroup C included 6 (16.7%) cases in which the gestational was partially located outside the outer contour of the cervix or uterus. RESULTS: The ß-HCG level upon admission was significantly lower in subgroup A than in subgroups B or C (11,075 ± 7109, 18,787 ± 16,585, and 58,273 ± 55,267 mIU/mL, respectively, P = .01). All subgroup C patients had repeated courses of MTX and surgical interventions (laparotomy, uterine artery embolization, and operative hysteroscopy) at double the rate of subgroups A or B (100, 50, and 40.9%, respectively, P = .036). The duration of hospitalization was significantly shorter in subgroup A than in subgroups B or C (1.9 ± 1.5, 2.1 ± 1.1, and 5.4 ± 4.9 days, P = .01). CONCLUSIONS: The outcome according to Delphi consensus criteria for defining CSP in early gestation has implications for clinical decision-making, patient care, and the follow-up of CSP.

Intraoperative ultrasound during repeat cesarean delivery facilitates sampling of uterine scar tissue.

OBJECTIVES: Histological examination of uterine scars provides insight into uterine wound healing and helps to develop prevention methods of uterine wall rupture after previous uterine surgery. Therefore, exact intraoperative scar identification is needed for specimen collection from the actual scar tissue. The aim of this study was to correlate pre- and intraoperative ultrasound measurements of the lower uterine segment (LUS) with histological findings of scar tissue and to evaluate the relevance of intraoperative ultrasound. METHODS: In a prospective observational study, preoperative and intraoperative sonographic measurements of the LUS thickness were performed in 33 women with a history of at least one cesarean delivery. Intraoperative ultrasound with a linear transducer placed directly on the uterus identified the scar area and uterotomy was performed 2 cm cranially. Tissue samples were taken after extraction of the fetus, embedded in paraffin wax, and stained according to Gomori Trichrome to identify scar tissue. Collagen content was evaluated with imaging software Fiji (NIH, Bethesda, USA). Preoperative and intraoperative sonographic measurements were correlated with histologic evidence of scar tissue. RESULTS: Histological evidence of scar tissue was found in 11 out of 33 samples with significantly lower ultrasonographic thickness of the lower uterine segment compared to the other 22 samples, both antepartum (1.4 mm [1.3-1.9] vs. 2.0 mm [1.6-2.6], p=0.03) and intrapartum (1.6 mm [1.3-1.9] vs. 3.7 mm [2.0-4.7], p<0.01). Intraoperative ultrasound had a significantly higher predictive power (AUC difference 0.18 [0.03-0.33], p=0.01). CONCLUSIONS: Intraoperative sonography identifies the uterine wall area with histologically confirmable scar tissue far better than preoperative sonography.

Ultrasound discrimination between placenta accreta spectrum and urinary bladder varices.

Distinguishing between urinary bladder varices and retroplacental neovascularization in placenta accreta spectrum in high-risk patients with placental previa is a diagnostic challenge since they have similar appearances on prenatal ultrasound. Placenta accreta spectrum is associated with massive obstetric haemorrhage while the presence of urinary bladder varices in pregnancy poses a lower surgical risk. Since the clinical implications and management approach for both conditions are entirely different, false positive diagnoses have iatrogenic consequences. In this article, we share our experiences in differentiating these two phenomena on prenatal ultrasound supported by ultrasound and intraoperative images.

Unraveling the enigma: A case of dynamic morphological changes in the niche at 25 weeks of gestation recapitulating the ontogenesis of uterine scar dehiscence.

We present the first report of a case with a peculiar configurational change in the lower uterine segment detected during transvaginal ultrasonography observation over a short period of time at 25 weeks of gestation, predicting the presence of uterine scar dehiscence at term.

Adipocytes in the Uterine Wall during Experimental Healing and in Cesarean Scars during Pregnancy.

We have suggested that adipocytes in uterine scars may affect the development of the placenta accrete spectrum (PAS). In the experimental part, we explored adipocytes in the uterine wall by the twelfth sexual cycle after surgery. In the clinical part, we investigated adipocyte clusters in the cesarean scar of pregnant women with and without PAS. The uterine wall was evaluated in gross and histological sections using morphometry, histochemistry (hematoxylin and eosin stain, Mallory stain), and immunohistochemistry for FABP4 (adipocyte markers), CD68, CD163, CD206 (macrophages), CD 34 (endothelium), cytokeratin 8 (epithelium), aSMA (smooth muscle cells). The design included an experimental study on Sprague-Dawley rats (n = 18) after a full-thickness surgical incision on the seventh (n = 6), 30th (n = 6), and 60th day (n = 6). The clinical groups include pregnant women without uterine scars (n = 10), pregnant women with a uterine scar after previous cesarean sections (n = 10), and women with PAS (n = 11). Statistical processing was carried out using nonparametric methods. Comparisons were conducted using the Mann-Whitney U-test and Kruskal-Wallis test. Statistical significance was considered at p < 0.05. On the seventh day, the rat uterine horn was enveloped by adipose tissue, which contained crown-like structures with FABP4+, CD68+, CD206+, and CD163+ cells. FABP4+ cells in the uterine wall were absent by the 30th day. The number of CD206+ and CD163+ cells in the adipose tissue decreased by the 30th day. On the 60th day, the attachment of fat tissue was revealed in the form of single strands. The serous layer around the damaged area totally recovered on the 60th day. FABP4+ cells were not detected in the uterine wall samples from pregnant women without a previous cesarean section. Adipocytes were found in the scar during non-complicated pregnancy and with PAS. Reducing the number of CD68+ cells in adipocyte clusters, there were in myometrium with PAS. Increased CD206+ and CD163+ cells were revealed in uterine adipocyte clusters of the group. According to the experimental finding, adipocytes should be absent in the uterine wall by the 12th sexual cycle after a full-thickness surgical incision. The presence of adipocyte clusters in cesarean scar indicated the disturbance of cell interaction. Differences in the numbers of CD206 and CD163 cells in adipocyte clusters between groups with and without PAS may be indirect evidence that uterine adipocytes affect the development of PAS.

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.

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.

Cesarean scar pregnancy.

OBJECTIVE: To summarize the current knowledge on pregnancy in a cesarean scar. METHODOLOGY: A literature review on the topic using the PubMed database. RESULTS: Gravidity in a cesarean scar is a relatively new type of ectopic pregnancy that will be an increasingly common problem in an era of increasing cesarean section rates. It is still a relatively rare event, occurring in about 6% of the population. Diagnosis is based primarily on ultrasound examination and is essential early on in pregnancy. The pathogenesis of the disease is due to a disorder of the basal layer of the endometrium and can lead to conditions that we refer to as placenta accreta spectrum. The management is completely individualized and depends on hCG values, ultrasound findings, fetal viability, the wishes of the pregnant woman and the experience of the gynecologist concerned. CONCLUSION: This is still a rare occurrence of ectopic pregnancy but with increasing potential. The solution is completely individualized based on a precise and early ultrasound diagnosis.

Position and integrity of uterine scar are determined by degree of cervical dilatation at time of Cesarean section.

OBJECTIVE: Abnormal placental invasion is more common after an elective Cesarean delivery, suggesting that prelabor Cesarean section (CS) increases the likelihood of the CS scar being above the internal cervical os and predisposing to a scar pregnancy in the future. The aim of this study was to assess the location and integrity of the CS scar in postpartum women delivered by CS at different stages of labor. METHODS: This was a prospective cohort study of women at term who underwent a CS for the first time. In all women, cervical dilatation was determined by digital examination at the time of the CS. All patients had a transvaginal ultrasound examination to assess the location of the CS scar in relation to the internal cervical os, as well as the presence of a scar niche. RESULTS: A total of 407 pregnant women were recruited into the study: 103 with cervical dilatation ≤ 2 cm, 261 with cervical dilatation 3-7 cm and 43 with cervical dilatation ≥ 8 cm at the time of the CS. A statistically significant correlation was observed between cervical dilatation at the time of the CS and the position of the CS scar. The scar was positioned in the uterus above the internal cervical os in 97.1% (100/103) of women delivered at a cervical dilatation of 0-2 cm, whereas the scar was located at or below the internal cervical os in 97.7% (42/43) of cases delivered at a cervical dilatation of 8-10 cm (P < 0.001). A uterine-scar defect (niche) was observed in 38.1% (64/168) of women with the scar located above, compared with 18.0% (43/239) of those with the scar situated at or below, the internal cervical os (P < 0.001). CONCLUSIONS: Prelabor and early-labor Cesarean delivery are associated with an increased prevalence of a scar in the uterine cavity as well as a scar niche. CS in late labor is associated with the uterine scar being situated in the endocervical canal and with a lower incidence of a niche. The position and integrity of the CS scar after prelabor and early-labor Cesarean delivery explain the predisposition to abnormal placental invasion in subsequent pregnancy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Single- or double-layer uterine closure techniques following cesarean: A randomized trial.

INTRODUCTION: Cesarean deliveries are commonly performed throughout the world. Although the uterine closure technique following this procedure may influence how the uterine scar heals, there is insufficient evidence for choosing the appropriate technique and so preventing long-term negative consequences. This prospective, randomized study examined the effects of single- and double-layer uterine closure techniques on uterine scar healing following cesarean delivery. MATERIAL AND METHODS: This study assessed a total of 282 women aged 18-45 years who were in gestational weeks 24-41 of singleton pregnancies. None had previously undergone uterine surgeries. These participants completed their first cesarean deliveries at the time of study and were randomized into the following two treatment groups: single-layer closure with locking and double-layer closure with locking in the first layer, but not in the second layer (NCT03629028). However, the decidua was not included for treatment in either group. Participants were evaluated at 6-9 months after cesarean section by saline infusion sonohysterography to assess cesarean delivery scar defects. These procedures were conducted by experienced sonographers who were not aware of the uterine closure technique. RESULTS: Of the 225 final participants, 109 received the single-layer closure technique, whereas 116 received the double-layer technique. The niche rates were 37% (n = 40) for the single-layer group and 45.7% (n = 53) for the double-layer group (P = .22, relative risk 1.4, 95% CI = 0.8-4.4). CONCLUSIONS: The single- and double-layer closure techniques did not produce different impacts on uterine scar niche development.

Association of peripartum management and high maternal blood loss at cesarean delivery for placenta accreta spectrum (PAS): A multinational database study.

INTRODUCTION: Placenta accreta spectrum (PAS) carries a high burden of adverse maternal outcomes, especially significant blood loss, which can be life-threatening. Different management strategies have been proposed but the association of clinical risk factors and surgical management options during cesarean delivery with high blood loss is not clear. MATERIAL AND METHODS: In this international multicenter study, 338 women with PAS undergoing cesarean delivery were included. Fourteen European and one non-European center (USA) provided cases treated retrospectively between 2008 and 2014 and prospectively from 2014 to 2019. Peripartum blood loss was estimated visually and/or by weighing and measuring of volume. Participants were grouped based on blood loss above or below the 75th percentile (>3500 ml) and the 90th percentile (>5500 ml). RESULTS: Placenta percreta was found in 58% of cases. Median blood loss was 2000 ml (range: 150-20 000 ml). Unplanned hysterectomy was associated with an increased risk of blood loss >3500 ml when compared with planned hysterectomy (adjusted OR [aOR] 3.7 [1.5-9.4], p = 0.01). Focal resection was associated with blood loss comparable to that of planned hysterectomy (crude OR 0.7 [0.2-2.1], p = 0.49). Blood loss >3500 ml was less common in patients undergoing successful conservative management (placenta left in situ, aOR 0.1 [0.0-0.6], p = 0.02) but was more common in patients who required delayed hysterectomy (aOR 6.5 [1.7-24.4], p = 0.001). Arterial occlusion methods (uterine or iliac artery ligation, embolization or intravascular balloons), application of uterotonic medication or tranexamic acid showed no significant effect on blood loss >3500 ml. Patients delivered by surgeons without experience in PAS were more likely to experience blood loss >3500 ml (aOR 3.0 [1.4-6.4], p = 0.01). CONCLUSIONS: In pregnant women with PAS, the likelihood of blood loss >3500 ml was reduced in planned vs unplanned cesarean delivery, and when the surgery was performed by a specialist experienced in the management of PAS. This reinforces the necessity of delivery by an expert team. Conservative management was also associated with less blood loss, but only if successful. Therefore, careful patient selection is of great importance. Our study showed no consistent benefit of other adjunct measures such as arterial occlusion techniques, uterotonics or tranexamic acid.