Placenta Accreta Spectrum Diagnosis Challenges and Controversies in Current Obstetrics: A Review

Grading magnetic resonance imaging signs for diagnosing invasive placenta accreta spectrum disorders

INTRODUCTION

Placenta accreta spectrum (PAS) disorders result from abnormal placental attachment, leading to varying degrees of myometrial invasion. Magnetic resonance imaging (MRI) plays a crucial role in assessing the depth and extent of placental invasion. This study aims to evaluate the correlation between quantified MRI findings and the diagnosis of PAS, as classified according to the FIGO system.

MATERIALS AND METHODS

A retrospective analysis was conducted on 556 high-risk PAS patients, defined as those with placenta previa or a history of previous cesarean sections. Ten predefined MRI signs were assessed board certified radiologists. Multivariate logistic regression was used to identify independent predictors of invasive PAS. The positive predictive value (PPV) and negative predictive value (NPV) were calculated to assess the diagnostic performance of signs.

RESULTS

Among the 556 cases, 150 (26.98 %) were classified as non-PAS, 180 (32.37 %) as placenta accreta, 158 (28.42 %) as placenta increta, and 68 (12.23 %) as placenta percreta. Four MRI signs were identified as significant predictors of invasive PAS: bladder wall interruption (odd ratio [OR] = 160.17), placental ischemic infarction (OR = 19.91), placental protrusion (OR = 14.66), and myometrial thinning (OR = 14.07). The PPV of these signs ranged from 70 % to 85 %, while the NPV ranged from 65 % to 72 %. Multivariate analysis confirmed these MRI findings as independent predictors of invasive PAS.

CONCLUSIONS

This study identified four key MRI signs as reliable predictors of invasive PAS, which can effectively inform clinical decision-making regarding surgical interventions, such as cesarean hysterectomy.

Foreword: Clinically Focused Insights on the Placenta and Umbilical Cord: An Evidence-based Symposium

In this symposium, we introduce a collection of reviews that delve into the diverse clinically relevant aspects of the placenta and umbilical cord. The symposium addresses placenta previa and abruption; pathology, genetics, and imaging of the placenta; infections of the placenta; and ischemic placental disease. The umbilical cord's essential function as a fetal lifeline is explored, with an emphasis on the clinical repercussions of its dysfunction, including vasa previa and other umbilical cord abnormalities. This curated collection of reviews, which synthesizes the placenta's and umbilical cord's fundamental role in maternal-fetal health, underscores the clinical importance of these structures in pregnancy.

Advances in Prenatal Diagnosis of Placenta Accreta Spectrum

Placenta accreta spectrum (PAS) involves abnormal placental attachment and can lead to severe complications such as postpartum hemorrhage and hysterectomy. Ultrasound is the main tool used to screen for PAS due to its non-invasive nature and convenience, although its accuracy depends on the skill of the operator. Magnetic Resonance Imaging has emerged as a supplementary tool, especially for complex cases or posterior placentas, providing more accurate anatomical detail and enabling the invasion depth and location to be assessed. This review summarizes recent advances in prenatal imaging for PAS, aiming to improve diagnostic accuracy and guide future research.

Efficacy of King's Combined Uterine Suture in Managing Placenta Accreta: A Retrospective Analysis

BACKGROUND Placenta accreta is a spectrum disorder that can include an abnormally adherent placenta to placental tissue that invades the endometrium and myometrium and results in hemorrhage during or after delivery. King's combined uterine suture is a combination of parauterine vascular ligation with longitudinal suturing of the lower uterine segment. This retrospective study aimed to evaluate outcomes from using King's combined uterine suture for hemostasis in 49 parturient women with placenta accreta spectrum (PAS). MATERIAL AND METHODS Clinical data of parturient women with placenta accreta in Fujian Maternal and Child Health Hospital from January 2020 to January 2023 were retrospectively collected. King's combined uterine suture ligation surgery was performed in these patients who had placenta accreta. Placenta accreta was diagnosed by the criteria for PAS. The outcomes of surgery and prognosis of newborns were analyzed. RESULTS A total of 49 parturient women were included and underwent successful intraoperative hemostasis without hysterectomy or ureteral injury. There were 4 cases of bladder rupture and 17 cases of uterine plastic surgery. The average intraoperative bleeding volume of the 49 patients was (507±162) mL. Patients had no long-term complications during postoperative follow-up. Apgar score of newborns was 9.67±0.77, and there was no asphyxia or neonatal death. CONCLUSIONS King's combined uterine suture ligation surgery is applied to placenta accreta, which not only has a definite and fast hemostatic effect, but can also effectively preserve the uterus.

The role of the intraplacental fetal artery in predicting the need for cesarean-hysterectomy in women at high risk for placenta accreta spectrum

INTRODUCTION

Prenatal determination of placenta accreta spectrum (PAS) and its severity is crucial, as it is a highly morbid condition. The aim was to investigate the intraplacental fetal artery (IFA) as a novel ultrasonographic marker in predicting cesarean-hysterectomy need in PAS.

METHODS

A prospective observational cohort study was conducted with a total of 62 women with placenta previa and ≥1 previous cesarean-section who were managed for PAS between September 2022 and January 2024. All women were classified according to the ultrasonographic classification system for prenatal PAS, and ultrasonographic assessments for IFA were performed. Odds ratios were calculated to test the association of IFA and other parameters related to PAS with cesarean-hysterectomy need. Receiver operating characteristic analysis was performed to evaluate the ability of maximum diameter (D-max) of IFA to predict cesarean-hysterectomy need.

RESULTS

The study was completed with 49 women who underwent a cesarean-section with uterus-sparing surgery (n = 22) and a cesarean-hysterectomy (n = 27). Outer placental-half extension of IFA and each 1 mm increase in IFA D-max >3.5 mm were associated with a 58.82- and 3.52-fold increased risk of cesarean-hysterectomy, respectively. An IFA D-max of >3.5 mm was associated with cesarean-hysterectomy need at any PAS stage [area under the curve (AUC) = 0.845, 95 % CI:0.71-0.93, p < 0.001)] and in PAS 2 patients (AUC = 0.750, 95 % CI:0.56-0.89, p = 0.010), in whom prenatal prediction of cesarean-hysterectomy need is difficult.

DISCUSSION

Evaluation of D-max and outer placental-half extension of IFA along with other markers of PAS improved the ability of ultrasonography to predict cesarean-hysterectomy need.

Assessment of serum levels and placental bed tissue expression of IGF-1, bFGF, and PLGF in patients with placenta previa complicated with placenta accreta spectrum disorders

OBJECTIVE

This study aims to detect the serum levels of IGF-1, bFGF, and PLGF and their expressions in placental bed tissues of patients with placenta previa complicated with PAS disorders.

METHODS

This case and control study included 40 multiparous pregnant women with complete placenta previa between 34 weeks and 38 weeks of gestation and they were divided into two groups: 25 patients with PAS (case group) and 15 patients without PAS (control group). The venous blood samples were collected 2 h before the cesarean section, and the placental bed tissues were taken intraoperatively at the placental implantation site and then were histologically examined to evaluate the gravity of the myometrial invasion of the placenta. According to FIGO PAS increasing grading, the 25 patients were also divided into three groups: PAS grade I group, PAS grade II group, and PAS grade III group. The concentrations of IGF-1, bFGF, and PLGF in serum were measured using ELISA, and the mean ratio of the relative mRNA expression of each biomarker in placental bed tissues was calculated using qRT-PCR. The staining intensity and the positive cells were quantitatively measured and expressed as means by using Image J software for IHC analysis.

RESULTS

IGF-1 had low serum levels and high placental bed expression in placenta previa patients with PAS disorders compared to those without PAS (all p < 0.0001). PLGF had high serum levels (p = 0.0200) and high placental bed expression (p < 0.0001) in placenta previa patients with PAS disorders compared to those without PAS. IGF-1 serum levels decreased up to PAS grade II (means were 24.3 ± 4.03, 21.98 ± 3.29, and 22.03 ± 7.31, respectively for PAS grade I, PAS grade II, PAS grade III groups, p = 0.0006). PLGF serum levels increased up to PAS grade II (means were 12.96 ± 2.74, 14.97 ± 2.56, and 14.89 ± 2.14, respectively for the three groups, p = 0.0392). However, IGF-1 and PLGF mRNA placental bed expression increased up to PAS grade III. The relative expression of mRNA means for the three groups was 3.194 ± 1.40, 3.509 ± 0.63, and 3.872 ± 0.70, respectively for IGF-1; and 2.784 ± 1.14, 2.810 ± 0.71, and 2.869 ± 0.48, respectively for PLGF (all p < 0.0001). Their IHC (immunohistochemical) staining also had increasing trends, but p > 0.05. bFGF was not significantly expressed in placenta previa with PAS disorders in most of the analysis sections (p > 0.05).

CONCLUSIONS

Low serum levels and high expression in placental bed tissues of IGF-1, or high serum levels and high expression in placental bed tissues of PLGF, may differentiate placenta previa patients with FIGO PAS grade I and PAS grade II from those without PAS disorders. However, they could not significantly predict the degree of placental invasiveness in FIGO PAS grades II and III.

Uterine window and placenta accreta spectrum in a dichorionic, diamniotic twin gestation complicated by postpartum hemorrhage

Cesarean scar defects encompass a spectrum of separation of the uterine layers that increase risk of uterine rupture during labor and delivery. When coupled with the presence of placenta accreta spectrum, a condition characterized by abnormal adherence to or invasion of the myometrium by the placenta, the risk of life-threatening hemorrhage significantly increases. As rates of cesarean delivery increase, it is important to understand the imaging findings typical of both conditions. We present the case of a 30-year-old patient with a dichorionic, diamniotic twin gestation complicated by uterine window and placenta accreta spectrum.

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

INTRODUCTION

We 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.

METHOD

Fifty-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.

RESULT

The 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.

DISCUSSION

Preoperative MRI features and IVIM parameters may be used to predict poor outcomes in patients with invasive placental disorders like PAS.

Addressing Diagnosis, Management, and Complication Challenges in Placenta Accreta Spectrum Disorder: A Descriptive Study

INTRODUCTION

In light of increased cesarean section rates, the incidence of placenta accreta spectrum (PAS) disorder is increasing. Despite the establishment of clinical practice guidelines offering recommendations for early and effective PAS diagnosis and treatment, antepartum diagnosis of PAS remains a challenge. This ultimately risks poor mental health and poor physical maternal and neonatal health outcomes.

CASE DESCRIPTIONS

This case series details the experience of two high-risk patients who remained undiagnosed for PAS until they presented with antenatal hemorrhage, leading ultimately to necessary, complex surgical interventions, which can only be optimally provide in a tertiary care center. Patient 1 is a 37-year-old woman with a history of three cesarean sections, which elevates her risk for PAS. She had placenta previa detected at 19 weeks, and placenta percreta diagnosed upon hemorrhage. During a hysterectomy, invasive placenta was found in the patient's bladder, leading to a cystotomy and right ureteric reimplantation. After discharge, she was diagnosed with a vesicovaginal fistula, and is currently awaiting surgical repair. Patient 2 is a 34-year-old woman with two previous cesarean sections. The patient had complete placenta previa detected at 19- and 32-week gestation scans. She presented with antepartum hemorrhage at 35 weeks and 2 days. An ultrasound showed thin myometrium at the scar site with significant vascularity. A hysterectomy was performed due to placental attachment issues, with significant blood loss. Both patients were at high risk for PAS based on past medical history, risk factors, and pathognomonic imaging findings.

DISCUSSION

We highlight the importance of the implementation of clinical guidelines at non-tertiary healthcare centers. We offer clinical-guideline-informed recommendations for radiologists and antenatal care providers to promote early PAS diagnosis and, ultimately, better patient and neonatal outcomes through increased access to adequate care.

Characteristics and treatment for severe postpartum haemorrhage in different midwifery hospitals in one district of Beijing in China: an institution-based, retrospective cohort study

OBJECTIVE

To identify the characteristics and treatment approaches for patients with severe postpartum haemorrhage (SPPH) in various midwifery institutions in one district in Beijing, especially those without identifiable antenatal PPH high-risk factors, to improve regional SPPH rescue capacity.

DESIGN

Retrospective cohort study.

SETTING

This study was conducted at 9 tertiary-level hospitals and 10 secondary-level hospitals in Haidian district of Beijing from January 2019 to December 2022.

PARTICIPANTS

The major inclusion criterion was SPPH with blood loss ≥1500 mL or needing a packed blood product transfusion ≥1000 mL within 24 hours after birth. A total of 324 mothers with SPPH were reported to the Regional Obstetric Quality Control Office from 19 midwifery hospitals.

OUTCOME MEASURES

The pregnancy characteristics collected included age at delivery, gestational weeks at delivery, height, parity, delivery mode, antenatal PPH high-risk factors, aetiology of PPH, bleeding amount, PPH complications, transfusion volume and PPH management. SPPH characteristics were compared between two levels of midwifery hospitals and their association with antenatal PPH high-risk factors was determined.

RESULTS

SPPH was observed in 324 mothers out of 106 697 mothers in the 4 years. There were 74.4% and 23.9% cases of SPPH without detectable antenatal PPH high-risk factors in secondary and tertiary midwifery hospitals, respectively. Primary uterine atony was the leading cause of SPPH in secondary midwifery hospitals, whereas placental-associated disorders were the leading causes in tertiary institutions. Rates of red blood cell transfusion over 10 units, unscheduled returns to the operating room and adverse PPH complications were higher in patients without antenatal PPH high-risk factors. Secondary hospitals had significantly higher rates of trauma compared with tertiary institutions.

CONCLUSION

Examining SPPH cases at various institutional levels offers a more comprehensive view of regional SPPH management and enhances targeted training in this area.

Fostering Excellence in Obstetrical Surgery

Introduction

This obstetric surgery review is directed toward the common obstetrical surgeries (caesarean delivery, VBAC/TOLAC, operative vaginal delivery, placenta accreta spectrum) with evidence for quality and safety to allow for obstetrical outcome excellence.

Materials and Methods

This focused scoping review has used a structured process for article identification and inclusion for each of the focused surgeries.

Results

The review results provide an obstetrical surgery (OS) overview for caesarean delivery, vaginal birth after caesarean delivery and/or trial of labor after caesarean delivery, operative vaginal delivery, placenta accreta spectrum; considerations for quality and safety variance due to non-clinical human factors; quality improvement (QI) tools; OS QI implementation cohorts; implementation considering certain barriers and solutions.

Conclusion

Administrative health care systems and obstetrical surgery care providers cannot afford, not to consider and implement, certain evidenced-based "bottom-up/top-down" processes for quality and safety, as the patients will demand the quality and the safety, but the lawyers should not have to enforce it.