Placenta Accreta Spectrum Disorders Research Articles

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

To identify the risk factors for placenta accreta spectrum (PAS) disorders in women without prior cesarean section (CS). This retrospective case-control study investigated patients without prior CS who gave birth at Peking University Third Hospital between January 1, 2015 and December 31, 2021. Patients diagnosed with PAS according to the clinical diagnostic criteria of the 2019 International Federation of Gynecology and Obstetrics (FIGO) classification were included as the study group. Patients were matched as the control group according to delivery date and placenta previa, in a 1:2 allocation ratio. Maternal characteristics were compared between the two groups. The study included 348 patients in the study group and 696 in the control group. The multivariate analysis showed that the independent risk factors of PAS consisted of operative hysteroscopy (once: adjusted odds ratio [aOR] 2.38, 95% CI 1.28-4.24, P = 0.006; twice or more: aOR 5.43, 95% CI 1.04-28.32, P = 0.045), uterine curettage (once: aOR 2.54, 95% CI 1.80-3.58, P < 0.001; twice: aOR 3.01, 95% CI 1.81-5.02, P < 0.001; three or more times: aOR 9.18, 95% CI 4.64-18.18, P < 0.001), multifetal pregnancy (aOR 5.64, 95% CI 3.01-10.57, P < 0.001), adenomyosis (aOR 2.77, 95% CI 1.23-6.22, P = 0.014), invitro fertilization (aOR 1.51, 95% CI 1.04-2.20, P = 0.030) and pre-eclampsia (aOR 2.72, 95% CI 1.36-5.45, P = 0.005), and the independent protective factor was being multiparous (aOR 0.37, 95% CI 0.25-0.54, P < 0.001). After controlling the effect of placenta previa, we found that patients with PAS without prior CS had unique maternal characteristics. Classification and quantification of the intrauterine surgeries they have undergone is essential for identifying high-risk patients. Early identification of high-risk groups by risk factors has the potential to improve the prognosis considerably.

Matrix Metalloproteinase-9 in the Etiopathogenesis of Placenta Accreta Spectrum: A Literature Review

Abstract The recent increase in placenta accreta spectrum has been correlated with a rise in the rate of cesarean sections. A recent study provides evidence that hampered wound healing results in cesarean scar defects that lead to a failure in the normal process of decidualization and deeper adherence of trophoblasts. Matrix metalloproteinase (MMP) is crucial in every step of wound healing as it alters the wound matrix, facilitating cell migration, as well as tissue remodeling. MMP-9 expression is higher in placental and decidual tissue in cases of placenta accreta. Based on these findings, assessment of MMP-9 expression can shed new light on the etiopathology of placenta accreta spectrum disorder and can be a potential diagnostic marker.

The predictive value of conventional magnetic resonance imaging combined with intravoxel incoherent motion parameters for evaluating maternal and neonatal clinical outcomes in patients with placenta accreta spectrum disorders

IntroductionWe aimed to identify factors predictive of adverse maternal and neonatal outcomes in patients with placenta accreta spectrum (PAS) disorders using magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) parameters. MethodFifty-six normal singleton pregnancies at 33-39 weeks of gestation underwent MRI examination at 1.5 T. The IVIM parameters were obtained from the placenta. The correlation between the f value and postpartum hemorrhage (PPH) and between the f value and transfused units of red blood cells (RBCs) was estimated by linear regression. The correlation between various influencing factors (clinical risk factors, MRI features, and IVIM parameters) and poor outcomes was investigated using univariate and multivariate analyses. ResultThe interobserver agreement ranged from fair to excellent (k = 0.30–0.88). Multivariate analyses showed that previous cesarean sections, low signal intensity bands on T2WI and the D value were independent risk factors for adverse outcomes. The combination of three risk factors demonstrated the highest AUC of 0.903, with a sensitivity and specificity of 73.10% and 96.90%, respectively. Last, f was positively correlated with PPH and units of RBCs transfused. DiscussionPreoperative MRI features and IVIM parameters may be used to predict poor outcomes in patients with invasive placental disorders like PAS.

Imaging of Antepartum and Postpartum Hemorrhage.

Severe obstetric hemorrhage is a leading cause of maternal mortality and morbidity worldwide. Major hemorrhage in the antepartum period presents potential risks for both the mother and the fetus. Similarly, postpartum hemorrhage (PPH) accounts for up to a quarter of maternal deaths worldwide. Potential causes of severe antepartum hemorrhage that radiologists should be familiar with include placental abruption, placenta previa, placenta accreta spectrum disorders, and vasa previa. Common causes of PPH that the authors discuss include uterine atony, puerperal genital hematomas, uterine rupture and dehiscence, retained products of conception, and vascular anomalies. Bleeding complications unique to or most frequently encountered after cesarean delivery are also enumerated, including entities such as bladder flap hematomas, rectus sheath and subfascial hemorrhage, and infectious complications of endometritis and uterine dehiscence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Javitt and Madrazo in this issue.

Efficacy and safety of prophylactic balloon occlusion in the management of placenta accreta spectrum disorder: a retrospective cohort study

ObjectivePlacenta accreta spectrum disorder (PAS) is a serious obstetric complication associated with significant maternal morbidity and mortality. Prophylactic balloon occlusion (PBO), as an intravascular interventional therapies, has emerged as a potential management strategy for controlling massive hemorrhage in patients with PAS. However, current evidence about the clinical application of PBO in PAS patients are still controversial. This study aimed to evaluate the effectiveness and safety of PBO in the management of PAS.MethodsA retrospective cohort study including PAS patients underwent cesarean delivery was conducted in a tertiary hospital from January 2015 to March 2022. Included PAS patients were further divided into balloon and control groups by whether PBO was performed. Groups were compared for demographic characteristics, intraoperative and postoperative parameters, maternal and neonatal outcomes, PBO-related complication and follow up outcomes. Additionally, multivariate-logistic regression analysis was performed to determine the definitive associations between PBO and risk of massive hemorrhage and hysterectomy.ResultsA total of 285 PAS patients met the inclusion criteria were included, of which 57 PAS patients underwent PBO (PBO group) and 228 women performed cesarean section (CS) without PBO (control group). Irrespective of the differences of baseline characteristics between the two groups, PBO intervention did not reduce the blood loss, hysterectomy rate and postoperative hospital stay, but it prolonged the operation time and increased the cost of hospitalization (All P < 0.05) Additionally, there were no significant differences in postoperative complications, neonatal outcomes, and follow-up outcomes(All P > 0.05). In particular, patients undergoing PBO were more likely to develop the venous thrombosis postoperatively (P = 0.001). However, multivariate logistic regression analysis showed that PBO significantly decreased the risk of massive hemorrhage (OR 0.289, 95%CI:0.109–0.766, P = 0.013). The grade of PAS and MRI with S2 invasion were the significant risk factors affecting massive hemorrhage(OR:6.232 and OR:5.380, P<0.001).ConclusionPBO has the potential to reduce massive hemorrhage in PAS patients undergoing CS. Obstetricians should, however, be aware of potential complications arising from the PBO. Additionally, MRI with S2 invasion and PAS grade will be useful to identify PAS patients who at high risk and may benefit from PBO. In brief, PBO seem to be a promising alternative for management of PAS, yet well-designed randomized controlled trials are needed to convincingly demonstrate its benefits and triage the necessity of PBO.

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function.

The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions. A literature search was performed in the PubMed and Google Scholar databases. Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics. The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

Quality evaluation of clinical practice guidelines for placenta accreta spectrum disorders

IntroductionWe evaluated the quality of the published clinical practice guidelines on placenta accreta spectrum (PAS) disorders to provide reference for the development of high-quality PAS guidelines. MethodsChina National Knowledge Infrastructure (CNKI), Wan Fang, PubMed, Embase, Web of Science, and Cochrane Library were systematically searched. Quality assessments were conducted using the appraisal of guidelines for research and evaluation (AGREE) II framework and Reporting Items for practice Guidelines in Healthcare (RIGHT) checklist. Intraclass correlation coefficients (ICCs) were used to measure the agreement among reviewers. ResultsIn total, 13 guidelines from different countries, published between 2015 and 2021 were included. There included 9 official guidelines, 3 consensuses, and 1 standard reference and covered subjects including epidemiology, diagnosis and treatment. The mean standardized scores across 6 domains (scope and purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability, and editorial independence) were 53.63%, 27.35%, 33.57%, 72.01%, 19.39% and 41.02%, respectively. Of the 13 guidelines, 11 were classified as grade B, whereas 2 as grade C. According to the RIGHT checklist, the overall reporting rate of the 13 guidelines ranged from 28.57% to 54.29%. ConclusionThe current guidelines for PAS demonstrate commendable methodological and reporting qualities. However, the methodological and reporting quality of PAS CPGs still need to be further improved, particularly in stakeholder involvement, the rigor of development, applicability, and editorial independence domains.

Diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol as a biomarker of placental blood circulation in patients with placenta accreta spectrum disorders: A proof-of-concept study

ObjectivesIncreasing trend of PAS (placenta accreta spectrum disorders) incidence is a major health concern as PAS is associated with high maternal morbidity and mortality during cesarean section. Prenatal identification of PAS is crucial for delivery planning and patients management. This study aims to explore whether diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol differs in PAS from normal placenta. MethodsWe enrolled 86 patients with PAS disorders and 40 pregnant women without PAS disorders. Each patient underwent intravoxel incoherent motion (IVIM) MRI sequence with 11 b-values. Placenta diffusion-derived vessel density (DDVD-b0b50) was the signal difference between b = 0 and b = 50 s/mm2 images. DDVD(b0b50) A/N was calculated as [accreta lesion DDVD(b0b50)]/ [normal placenta DDVD(b0b50)]. The correlation between DDVD and gestational age was explored using Spearman rank correlation. Differences of DDVD(b0b50) A/N in patients with normal placentas and with PAS, and in patients with different subtypes of PAS were explored. ResultsDDVD was negatively correlated with gestational age (p = 0.023, r = −0.359) in patients with normal placentas. DDVD(b0b50) A/N was significantly higher in patients with PAS (median:1.16, mean: 1.261) than normal placenta (median:1.02, mean: 1.032, p < 0.001) and especially higher in patients with placenta increta (median:1.14, mean: 1.278) and percreta (median: 1.20, mean: 1.396, p < 0.001). ConclusionAs a higher DDVD indicates higher physiological volume of micro-vessels in PAS, this study suggests DDVD can be a potential biomarker to evaluate the placenta perfusion.

Risk factors for placenta accreta spectrum disorders in women with any prior cesarean and a placenta previa or low lying: a prospective population-based study

This study aimed to identify the risk factors for placenta accreta spectrum (PAS) in women who had at least one previous cesarean delivery and a placenta previa or low-lying. The PACCRETA prospective population-based study took place in 12 regional perinatal networks from 2013 through 2015. All women with one or more prior cesareans and a placenta previa or low lying were included. Placenta accreta spectrum (PAS) was diagnosed at delivery according to standardized clinical and histological criteria. Of the 520,114 deliveries, 396 fulfilled inclusion criteria; 108 were classified with PAS at delivery. Combining the number of prior cesareans and the placental location yielded a rate ranging from 5% for one prior cesarean combined with a posterior low-lying placenta to 63% for three or more prior cesareans combined with placenta previa. The factors independently associated with PAS disorders were BMI ≥ 30, previous uterine surgery, previous postpartum hemorrhage, a higher number of prior cesareans, and a placenta previa. Finally, in this high-risk population, the rate of PAS disorders varies greatly, not only with the number of prior cesareans but also with the exact placental location and some of the women's individual characteristics. Risk stratification is thus possible in this population.

Life-Threatening Obstetrical Emergency: Spontaneous Uterine Rupture Associated with Placenta Percreta in the First Trimester of Pregnancy—Case Report and Literature Review

Background: The greatest risk for the occurrence of the placenta accreta spectrum (PAS) is represented by uterine scars, which most frequently result after cesarean sections. Uterine rupture is a rare condition and appears mainly in the third trimester of pregnancy. The association between these two conditions is extremely rare in the first trimester of pregnancy. Methods: We performed a systematic review of abnormal placental adhesions and spontaneous uterine ruptures in the first trimester of pregnancy. We also reported a case of spontaneous uterine rupture in a 12-week pregnancy that presented with massive hemoperitoneum and hemorrhagic shock. Results: A 33-year-old patient with two previous cesarean sections, at the twelfth week of pregnancy at the time to this visit to the emergency room, presented with syncope and intense pelvic–abdominal pain. A clinical examination and ultrasound scan established the diagnosis of hemoperitoneum and hemorrhagic shock. Surgical exploration was performed, uterine rupture was identified, and hemostasis hysterectomy was necessary. The histopathological results showed placenta percreta. There have been eight reported cases of spontaneous uterine rupture in the first trimester of pregnancy associated with PAS. In these cases, it was found that 62.5% of the patients had undergone at least one cesarean section in the past; in 75% of the cases, hysterectomy was performed; and, in 87.5% of the cases, the presence of placenta percreta was confirmed. Conclusions: A high rate of cesarean sections determines the increase in the incidence of placenta accreta spectrum disorders. The possible life-threatening complications caused by this pathology can be observed in early pregnancies.

Caesarean Hysterectomy for Placenta Accreta Spectrum in a Single Centre: A Series of 19 Cases

The objective of this study is to assess obstetric complications, blood loss, blood transfusion requirement, and maternal and fetal outcomes associated with the authors’ approach of Caesarean hysterectomy for placenta accreta spectrum disorders. Data were collected from case records of all females who underwent Caesarean hysterectomy between August 2013–August 2023 at Lifeline Multispeciality Hospital, Adoor, Kerala, India. There were 19 cases of Caesarean hysterectomy. The mean age was 33.63±2.90 years. Mean blood loss during surgery was 1.11±0.16 L, and the mean packed red blood cells transfused was 2.00±0.38 units. The mean gestational age of termination was 33 weeks and 5 days, and mean birth weight was 2.28±0.21 kg. There were no maternal or neonatal deaths. Placenta accreta spectrum should be managed in a multidisciplinary setup with the involvement of a senior experienced obstetrician. Early, careful bladder dissection before proceeding with hysterectomy will help in reducing haemorrhage, and in accelerating hysterectomy.

The MRI estimations of placental volume, T2 dark band volume, and cervical length correlate with massive hemorrhage in patients with placenta accreta spectrum disorders.

To identify whether placental volume, T2 dark band volume, and cervical length measured by MRI correlate with massive hemorrhage (MH) in patients with placenta accreta spectrum (PAS) disorders. A total of 163 pregnant women with PAS underwent preoperative MRI examination were divided into MH group and non-MH group. The placental volume, T2 dark band volume, and cervical length of PAS patients were measured and evaluated their ability to identify MH in patients with PAS. Patients with MH had a significantly larger placental volume, larger T2 dark band volume, and shorter cervical length than patients without MH (all P<0.001). Multivariable logistic regression showed that placental volume (>890cm3), T2 dark band volume (>35cm3), and cervical length (<30mm) were significant independent risk factor in identification of MH. In all PAS patients, a positive linear correlation was found between placental volume and amount of blood loss (r=0.527), and between T2 dark band volume and amount of blood loss (r=0.642), and a negative linear correlation was found between cervical length and amount of blood loss (r=-0.597). When combined with the three MRI indicators, the sensitivity and specificity in identifying cases at high risk for MH were 91.638% and 94.051%, respectively, with area under the curve (AUC) of 0.923. The placental volume, T2 dark band volume, and cervical length might be used to predict MH in patients with PAS.

Collateral Round Ligament Arterial Supply of Placenta Accreta Spectrum and Considerations for Prophylactic Balloon Occlusion Catheter Placement

Internal iliac artery (IIA) balloon occlusion catheters have been commonly inserted to decrease the risk of postpartum hemorrhage in placenta accreta spectrum disorders; however, there has been mixed success in clinical studies. Placement of an infrarenal aortic balloon has shown more consistent effectiveness in recent studies. A possible reason for this is collateral arterial supply to the placenta from external iliac artery branches. Retrospective chart review was conducted of angiography images during prophylactic IIA balloon occlusion catheter insertion over a 7-year period. Sixty-two individual cases were identified. Digital subtraction angiography (DSA) was performed in 32 (52%) cases, and 20 (62%) showed collateral blood supply from branches of the external iliac arteries, namely the round ligament artery. In conclusion, a high proportion of placenta accreta spectrum cases have arterial blood supply from branches of the external iliac artery, which may explain the discrepancy in effectiveness seen between IIA and infrarenal aortic sites of balloon occlusion catheter placement.

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

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. 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. 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. 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. 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.

Comparing the Efficacy of Two-Dimensional Ultrasound and Three-Dimensional Power Doppler for Diagnosing Placenta Accreta Spectrum Disorders and Predicting Complications: A Prospective Cross-Sectional Study.

Comparing the Efficacy of Two-Dimensional Ultrasound and Three-Dimensional Power Doppler for Diagnosing Placenta Accreta Spectrum Disorders and Predicting Complications: A Prospective Cross-Sectional Study.

Incidence, risk factors and maternal outcomes of unsuspected placenta accreta spectrum disorders: a retrospective cohort study

BackgroundTo identify incidence and underlying risk factors for unsuspected placenta accreta spectrum (PAS) and compare the maternal outcomes between suspected and unsuspected cases in three large academic referral centers.MethodsA retrospective cohort study was conducted in three university-based tertiary referral centers from Jan 1st, 2013, to Dec 31st, 2022. All cases of PAS confirmed by pathology were included in the study. Unsuspected PAS cases were diagnosed at the time of delivery, while suspected cases served as the control group. Potential risk factors were compared between the two groups. Multivariable regression model was also performed to identify risk factors. Maternal outcomes were also evaluated.ResultsA total of 339 pathology-confirmed PAS cases were included in the study out of 415,470 deliveries, of which 35.4% (n = 120) were unsuspected cases. Unsuspected PAS cases were 7.9 times more likely to have a history of intrauterine adhesions (adjusted odds ratio [aOR] 7.93; 95% confidence interval [CI] 2.35–26.81), 7.0 times more likely to have a history of clinically confirmed PAS (aOR, 6.99; 95% CI 2.85–17.18), 6.3 times more likely to have a posterior placenta (aOR, 6.30; 95% CI 3.48–11.40), and 3.4 times more likely to have a history of placenta previa (aOR, 3.41; 95% CI 1.18–9.82). On the other hand, cases with gravidity > 3, placenta previa, and/or a history of previous cesarean delivery were more likely to be diagnosed antenatally (aOR 0.40, 0.19, 0.36; 95% CI 0.22–0.74, 0.09–0.40, 0.19–0.70). Although the suspected PAS group had a higher proportion of invasive cases and abdominal and pelvic organ injuries (74.4% vs. 25.8%, p < 0.001; 6.8% vs. 1.7%, p = 0.037), the maternal outcomes were more favorable in the sPAS group, with a lower median volume of 24-hour blood loss and blood product transfusion (estimated blood loss in 24 h, 1000 [800–2000] vs. 2000 [1400–2400], p < 0.001; RBC unit transfusion, 0 [0-800] vs. 800 [600–1000], p < 0.001; fresh-frozen plasma transfusion, 0 [0-450] vs. 600 [400–800], p < 0.001).ConclusionsOur findings indicate that 35% of patients with PAS were unsuspected prior to delivery. Factors associated with PAS being unsuspected prior to delivery include a history of intrauterine adhesions, a history of clinically confirmed PAS, a posterior placenta, and a history of placenta previa. Additionally, gravidity > 3, a history of previous cesarean delivery, and placenta previa increase the likelihood of antenatal diagnosis.

Factors and outcomes for placental anomalies: An umbrella review of systematic reviews and meta-analyses.

Placental anomalies, including placenta previa (PP), placenta accreta spectrum disorders (PAS), and vase previa (VP), are associated with several adverse foetal-neonatal and maternal complications. However, there is still a lack of robust evidence on the pathogenesis and adverse outcomes of the diseases. Through this umbrella review, we aimed to systematically review existing meta-analyses exploring the factors and outcomes for pregnancy women with placental anomalies. We searched PubMed, Embase, Web of Science, and the Cochrane Library from inception to February 2023. We used AMSTAR 2 to assess the quality of the reviews and estimated the pooled risk and 95% confidence intervals (CIs) for each meta-analysis. We included 34 meta-analyses and extracted 55 factors (27 for PP, 22 for PAS, and 6 for VP) and 16 outcomes (12 for PP, and 4 for VP) to assess their credibility. Seven factors (maternal cocaine use (for PP), uterine leiomyoma (for PP), prior abortion (spontaneous) (PP), threatened miscarriage (PP), maternal obesity (PP), maternal smoking (PAS), male foetus (PAS)) had high epidemiological evidence. Twelve factors and six outcomes had moderate epidemiological evidence. Twenty-two factors and eight outcomes showed significant association, but with weak credibility. We found varying levels of evidence for placental anomalies of different factors and outcomes in this umbrella review. PROSPERO: CRD42022300160.

Impact of 2 years of COVID-19 pandemic on preterm birth: Experience from a tertiary center of obstetrics in western Germany.

To compare preterm birth rates and reasons before and during the COVID-19-pandemic using a monocentric, retrospective study. Univariate analysis identified differences in rates and reasons for preterm birth and neonatal outcomes between the pre-pandemic period (January 1, 2018 to December 31, 2019) and during the pandemic (January 1, 2020 to December 31, 2021) among all births at our tertiary obstetrical center, the University Hospital of Essen. The cohort consisted of 6086 deliveries with 593 liveborn preterm singletons. During the pandemic, the incidence of preterm birth decreased (10.7% vs. 8.6%; odds ratio [OR] 0.79; 95% confidence interval [CI] 0.66-0.93). Spontaneous preterm birth (43.2% vs. 52.3%; OR 1.47; 95% CI 1.05-2.03), and placenta accreta spectrum disorder (3.7% vs. 8.2%; OR 2.36; 95% CI 1.15-4.84) were more common reasons for preterm birth. Placental dysfunction was a less common reason (34.1% vs. 24.3%; OR 0.62; 95% CI 0.43-0.90). Incidences of preterm premature rupture of membranes (28.13% vs. 40.25%; OR 1.72; 95% CI 1.12-2.43) and oligo-/anhydramnios (3.98% vs. 7.88%; OR 2.06; 95% CI 1.02-4.21) increased. Iatrogenic preterm birth decreased (54.5% vs. 49.5%; OR 0.81; 95% CI 0.58-1.13). Stillbirth rates did not change significantly. Among term births, there were fewer spontaneous deliveries (71.0% vs. 65.8%; OR 0.78; 95% CI 0.69-0.88), and more elective (12.3% vs. 15.1%; OR 1.26; 95% CI 1.07-1.50) and unplanned (9.3% vs. 10.9%; OR 1.19; 95% CI 0.98-1.45) cesarean sections. During the pandemic, more term newborns were admitted to neonatal intensive care (1.4% vs. 2.5%; OR 1.86; 95% CI 1.20-2.88). Our results, in line with data from other high-income countries, suggest that the likely reason for the decreased preterm birth rates is the underdiagnosis of pregnancy complications.

Current concepts in the use of cell salvage in obstetrics.

The worldwide leading cause of maternal death is severe maternal hemorrhage. Maternal hemorrhage can be profound leading to an entire loss of blood volume. In the past two decades, Patient Blood Management has evolved to improve patient's care and safety. In surgeries with increased blood loss exceeding 500 ml, the use of cell salvage is strongly recommended in order to preserve the patient's own blood volume and to minimize the need for allogeneic red blood cell (RBC) transfusion. In this review, recent evidence and controversies of the use of cell salvage in obstetrics are discussed. Numerous medical societies as well as national and international guidelines recommend the use of cell salvage during maternal hemorrhage. Intraoperative cell salvage is a strategy to maintain the patient's own blood volume and decrease the need for allogeneic RBC transfusion. Historically, cell salvage has been avoided in the obstetric population due to concerns of iatrogenic amniotic fluid embolism (AFE) or induction of maternal alloimmunization. However, no definite case of AFE has been reported so far. Cell salvage is strongly recommended and cost-effective in patients with predictably high rates of blood loss and RBC transfusion, such as women with placenta accreta spectrum disorder. However, in order to ensure sufficient practical experience in a multiprofessional obstetric setting, liberal use of cell salvage appears advisable.

Efficacy of Bakri Intrauterine Balloon in Managing Postpartum Hemorrhage: A Comparative Analysis of Vaginal and Cesarean Deliveries with Placenta Accreta Spectrum Disorders.

BACKGROUND The incidence of placenta accreta spectrum disorder (PAS) has been increasing in past decades, and women with PAS are a high-risk maternal population. This study aimed to explore the performance of Bakri intrauterine balloon tamponade (IUBT) in the treatment of postpartum hemorrhage (PPH), among those with and without PAS. MATERIAL AND METHODS The outcomes of 198 women who underwent treatment for PPH using IUBT were retrospectively analyzed. The demographics and maternal outcomes were analyzed for vaginal and cesarean births, with PAS and without PAS. RESULTS Compared to women with vaginal births (n=130), women who underwent cesarean births (n=68) showed a higher proportion of age ≥35 years (χ²=6.85, P=0.013), multiple births (χ²=13.60, P<0.001), preeclampsia (χ²=9.81, P=0.002), use of transabdominal IUBT (χ²=84.12, P<0.001) and pre-IUBT interventions (χ²=41.61, P<0.001), but had less infused volume of physiological saline (t=6.41, P<0.001). Women with PAS (n=105) showed a higher rate of pre-IUBT intervention (χ²=4.96, P=0.029) and transabdominal IUBT placement (χ²=9.37, P=0.002) than non-PAS women (n=93). The 36 women with PAS (n=36) showed a higher rate of preeclampsia (χ²=4.80, P=0.029), pre-IUBT intervention (χ²=5.90, P=0.015), and transabdominal IUBT placement (χ²=14.94, P<0.001) and a shorter duration from delivery to Bakri insertion (χ²=3.31, P=0.002), than non-PAS women (n=32). CONCLUSIONS PAS was a major cause of PPH at 198 vaginal and cesarean births. An accurate and timely pre-IUBT intervention and Bakri IUBT placement was critical for controlling PPH in cesarean births, especially in women with PAS.