Lower uterine segment scar assessment at 11-14 weeks' gestation to screen for placenta accreta spectrum in women with prior Cesarean delivery

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.

Placenta accreta spectrum in the second trimester: a clinical conundrum in procedural abortion care

Given the limitations in perioperative management strategies available at freestanding abortion clinics, abortion providers must commonly discern which patients are too complicated for procedural abortions at their center and must be referred for a hospital-based abortion. The need to transition from freestanding clinics to hospital-based abortion care can lead to delays in completing an abortion and significant social, economic, and psychological repercussions for the pregnant individual. One significant clinical problem that exemplifies the issue of who can be safely taken care of at a freestanding abortion clinic is when the placenta accreta spectrum is suspected. Placenta accreta spectrum is one of the major contributors to maternal morbidity and mortality in the United States, requiring coordinated multidisciplinary management to ensure the safest outcome for the pregnant individual. In this Clinical Opinion, we review the literature focused on identifying individuals at risk for placenta accreta spectrum >14+0 weeks gestation, delineate an algorithm to improve the frequency of timely referrals to hospital-based abortion providers, and propose next steps for future training goals and research on placenta accreta spectrum in the second trimester between complex family planning and maternal-fetal medicine subspecialists.

Early first-trimester transvaginal ultrasound screening for cesarean scar pregnancy in patients with previous cesarean delivery: analysis of the evidence

Obstetric hemorrhage is a leading cause of maternal morbidity and mortality. An important etiology of obstetric hemorrhage is placenta accreta spectrum. In the last 2 decades, there has been increased clinical experience of the devastating effect of undiagnosed, as well as late diagnosed, cases of cesarean scar pregnancy. There is a growing body of evidence suggesting that cesarean scar pregnancy is an early precursor of second- and third-trimester placenta accreta spectrum. As such, cesarean scar pregnancy should be diagnosed in the early first trimester. This early diagnosis could be achieved by introducing regimented sonographic screening in pregnancies of patients with previous cesarean delivery. This opinion article evaluates the scientific and clinical basis of whether cesarean scar pregnancy, with special focus on its early first-trimester discovery, complies with the accepted requirements of a screening test. Each of the 10 classical screening criteria of Wilson and Jungner were systematically applied to evaluate if the criteria were met by cesarean scar pregnancy, to analyze if it is possible and realistic to carry out screening in a population-wide fashion.

Bladder involvement in placenta accreta spectrum disorders: 2D US combined with the 3D crystal Vue and MRI comparative analysis

BACKGROUND

Placental accreta spectrum (PAS) disorder with bladder involvement is found to be associated with severe maternal and neonatal morbidity.When planning surgery or other treatments, a diagnosis and assessment of the invasiveness of placenta accreta spectrum disorder with bladder involvement are crucial.The detection of the depth of villi invasion can be accomplished with both MRI and US.The advent of three-dimensional Crystal Vue provides details additional information for scanning abnorma issue.

PURPOSE

Our goal was to compare and assess the diagnostic accuracy of 2D US combined with the 3D Crystal Vue and MRI in case of placenta accreta spectrum (PAS) involving the bladder.

MATERIALS AND METHODS

111 pregnancy patients between May 2019 and November 2023 at the First Affiliated Hospital of Anhui Medical University whether or not they had placenta previa were included in the study if they were diagnosed of having placenta increta (PI) or placenta percreta (PP).Both US and MRI were used to evaluate the pregnant women.Total 53 pregnant women were ultimately included in our analysis.53 patients were split into groups with and without bladder involvement. They underwent 2D US,3D Crystal Vue, and MRI.The visual features of every subject were noted. Next, we analyzed the fundamental information, associated medical history, pregnancy outcomes, and different US and MRI signals between the two groups. To determine the potential contributing factors of PAS complicated with bladder involvement, a univariate analysis was performed. A multivariable logistic regression analysis was performed to identify US and MRI findings predictive of bladder involvement in placenta accreta spectrum.

RESULTS

Multiple logistic regression analysis found that the bridging vessels (OR, 31.76,95% CI, 1.64-614.31,p = 0.022) and the tramline sign "fully" obliterated on Crystal Vue feature (OR, 68.92;95%CI,6.76-702.35,p < 0.001) were independently associated with an increased likelihood of bladder involvement. These findings when combined allowed for the prediction of bladder involvement with an 88.2% sensitivity, a 94.4% specificity, and an AUC of 0.933 (95% CI,0.829-0.983, p = 0.001). The results of the MRI logistic regression analysis were as follows: the three independent risk factors for bladder involvement were: Placental bulge (OR,57.99,95%CI,3.89-835.80,p = 0.003),Bladder wall interruption (OR,11.93, 95%CI, 1.60-88.85, p = 0.016), and Bladder vessel sign (OR, 9.75,95%CI, 1.43-66.21, p = 0.020).The joint diagnosis showed a sensitivity of 94.1% and specificity of 83.3%.The area under the curve was 0.942(95%CI,0.841-0.988). Regarding projected bladder involvement, there were no statistically significant differences between MRI and 2D integrated 3D Crystal Vue imaging.

CONCLUSION

Both 2D coupled 3D Crystal Vue imaging and MRI are highly effective for predicting bladder invasion.Ultrasound is preferred over MRI because it is more convenient and more affordable.Among them, the tramline sign "fully" obliterated on 3D Crystal Vue was a new and reliable US sign for detecting bladder involvement.

Development and validation of a nomogram for predicting placenta accreta spectrum in pregnancies with one previous cesarean delivery

OBJECTIVE

This study aimed to develop and validate a prenatal nomogram to predict the risk of placenta accreta spectrum (PAS) in women with one previous cesarean delivery.

METHODS

This retrospective study enrolled 5157 pregnant women with one previous cesarean delivery in China from January 2021 to January 2023. The nomogram was developed from a training cohort of 3612 pregnant women and tested on a validation cohort of 1545 pregnant women. Multivariate regression analysis was performed using the minimum value of the Akaike information criterion to select prognostic factors that can be included in the nomogram. We evaluated the nomogram by the area under the receiver operating characteristic (ROC) curve, calibration curves, and the decision curve analysis (DCA).

RESULTS

PAS occurred in 199 (5.51%) and 80 (5.18%) patients in the training and validation cohorts, respectively. Backward stepwise algorithms in the multivariable logistic regression model determined abortion, hypertensive disorders complicating pregnancy, fetal position, and placenta previa as relevant PAS predictors. The area under the ROC curve for the nomogram was 0.770 (95% confidence interval [CI] 0.733-0.807) and 0.791 (95% CI 0.730-0.853) for the training and validation cohorts, respectively. The calibration curves indicated that the nomogram's prediction probability was consistent with the actual probability. The DCA curve revealed that the nomogram has potential clinical benefit.

CONCLUSION

A prenatal nomogram was developed for PAS in our study, which helped obstetricians determine potential patients with PAS and make sufficient preoperative preparation to reduce maternal and neonatal complications.

Placental and umbilical cord anomalies detected by ultrasound as clinical risk factors of adverse perinatal outcome: Case series review of selected conditions. Part 1: Placental abnormalities

BACKGROUND

The aim of this extended review of multicenter case series is to describe the prenatal ultrasound features and pathogenetic mechanisms underlying placental and umbilical cord anomalies and their relationship with adverse perinatal outcome. From an educational point of view, the case series has been divided in three parts; Part 1 is dedicated to placental abnormalities.

METHODS

Multicenter case series of women undergoing routine and extended prenatal ultrasound and perinatal obstetric care.

RESULTS

Prenatal ultrasound findings, perinatal care, and pathology documentation in cases of placental pathology are presented.

CONCLUSIONS

Our case series review and that of the medical literature confirms the ethiopathogenetic role and involvement of placenta abnormalities in a wide variety of obstetrics diseases that may jeopardize the fetal well-being. Some of these specific pathologies are strongly associated with a high risk of poor perinatal outcome.

First-trimester screening for placenta accreta spectrum

In recent years, there has been a significant rise in cases of placenta accreta spectrum, a group of life-threatening placental disorders that can arise during childbirth. Early detection plays a crucial role in facilitating meticulous delivery planning, ultimately leading to a reduction in mortality and morbidity rates and improved overall outcomes. Although third-trimester ultrasound has traditionally been the primary method for prenatal screening for placenta accreta spectrum, it often falls short in identifying cases or diagnosis is too late for optimal delivery planning. Emerging evidence has highlighted the option of early detection of placenta accreta spectrum indicators during the first trimester of pregnancy. This comprehensive review delves into our current knowledge of sonographic assessment of the uterine cervicoisthmic complex in the first trimester, examining the location and appearance of cesarean scars and exploring first-trimester screening strategies, ultimately paving the way for improved maternal and neonatal outcomes.

Prediction of spontaneous preterm birth in women with previous full dilatation cesarean delivery

BACKGROUND

A previous term (≥37 weeks' gestation), full-dilatation cesarean delivery is associated with an increased risk for a subsequent spontaneous preterm birth. The mechanism is unknown. We hypothesized that the cesarean delivery scar characteristics and scar position relative to the internal cervical os may compromise cervical function, thereby leading to shortening of the cervical length and spontaneous preterm birth.

OBJECTIVE

This study aimed to determine the relationship of cesarean delivery scar characteristics and position, assessed by transvaginal ultrasound, in pregnant women with previous full-dilatation cesarean delivery with the risk of shortening cervical length and spontaneous preterm birth.

STUDY DESIGN

This was a single-center, prospective cohort study of singleton pregnant women (14 to 24 weeks' gestation) with a previous term full-dilatation cesarean delivery who attended a high-risk preterm birth surveillance clinic (2017-2021). Women underwent transvaginal ultrasound assessment of cervical length, cesarean delivery scar distance relative to the internal cervical os, and scar niche parameters using a reproducible transvaginal ultrasound technique. Spontaneous preterm birth prophylactic interventions (vaginal cervical cerclage or vaginal progesterone) were offered for short cervical length (≤25 mm) and to women with a history of spontaneous preterm birth or late miscarriage after full-dilatation cesarean delivery. The primary outcome was spontaneous preterm birth; secondary outcomes included short cervical length and a need for prophylactic interventions. A multivariable logistic regression analysis was used to develop multiparameter models that combined cesarean delivery scar parameters, cervical length, history of full-dilatation cesarean delivery, and maternal characteristics. The predictive performance of models was examined using the area under the receiver operating characteristics curve and the detection rate at various fixed false positive rates. The optimal cutoff for cesarean delivery scar distance to best predict a short cervical length and spontaneous preterm birth was analyzed.

RESULTS

Cesarean delivery scars were visualized in 90.5% (220/243) of the included women. The spontaneous preterm birth rate was 4.1% (10/243), and 12.8% (31/243) of women developed a short cervical length. A history- (n=4) or ultrasound-indicated (n=19) cervical cerclage was performed in 23 of 243 (9.5%) women; among those, 2 (8.7%) spontaneously delivered prematurely. A multiparameter model based on absolute scar distance from the internal os best predicted spontaneous preterm birth (area under the receiver operating characteristics curve, 0.73; 95% confidence interval, 0.57-0.89; detection rate of 60% for a fixed 25% false positive rate). Models based on the relative anatomic position of the cesarean delivery scar to the internal os and the cesarean delivery scar position with niche parameters (length, depth, and width) best predicted the development of a short cervical length (area under the receiver operating characteristics curve, 0.79 [95% confidence interval, 0.71-0.87]; and 0.81 [95% confidence interval, 0.73-0.89], respectively; detection rate of 73% at a fixed 25% false positive rate). Spontaneous preterm birth was significantly more likely when the cesarean delivery scar was <5.0 mm above or below the internal os (adjusted odds ratio, 6.87; 95% confidence interval, 1.34-58; P =.035).

CONCLUSION

In pregnancies following a full-dilatation cesarean delivery, cesarean delivery scar characteristics and distance from the internal os identified women who were at risk for spontaneous preterm birth and developing short cervical length. Overall, the spontaneous preterm birth rate was low, but it was significantly increased among women with a scar located <5.0 mm above or below the internal cervical os. Shortening of cervical length was strongly associated with a low scar position. Our novel findings indicate that a low cesarean delivery scar can compromise the functional integrity of the internal cervical os, leading to cervical shortening and/or spontaneous preterm birth. Assessment of the cesarean delivery scar characteristics and position seem to have use in preterm birth clinical surveillance among women with a previous, full-dilatation cesarean delivery and could better identify women who would benefit from prophylactic interventions.

Ultrasound-guided suction curettage followed by cervico-isthmic placement of foley three-way catheter for cesarean scar pregnancy's treatment. Retrospective study

OBJECTIVES

Cesarean scar pregnancy (CSP) is a rare dangerous condition with still no consensus on standard treatment. Suction curettage has been used as the first-line treatment for CSP with controversial outcomes. This study evaluates efficacy of ultrasound-guided suction curettage (UGSC) followed by cervical-isthmic placement of silicon semirigid three-way foley catheter.

MATERIALS AND METHODS

This study included 24 women with CSP. Preoperative ultrasound study was conducted. UGSC followed by placement of catheter was performed in all patients. The success rate and incidence of major complication, surgical time and hospital stay were recorded.

RESULTS

The success rate of UGSC followed by placement of foley catheter was 100%, effectively reduced major complications and none of the patients had a blood loss higher than 900 ml. Median hospital stay was 2 days and median foley stay was 1 day. Surgery had limited last with a median of 17 minutes.

CONCLUSION

UGSC followed by foley placement is a safe effective treatment for CSP with a clinical resolution of 100%. The catheter is easy to place under ultrasound guidance and prevents bleeding, reducing major procedures to solve the bleeding. Suction curettage in CSP treatment should be performed under ultrasound guidance and followed by cervical-isthmic placement of foley balloon.

The prenatal diagnostic indicators of placenta accreta spectrum disorders

Placenta accreta spectrum (PAS) disorders refers to a heterogeneous group of anomalies distinguished by abnormal adhesion or invasion of chorionic villi through the myometrium and uterine serosa. PAS frequently results in life-threatening complications, including postpartum hemorrhage and hysterotomy. The incidence of PAS has increased recently as a result of rising cesarean section rates. Consequently, prenatal screening for PAS is essential. Despite the need to increase specificity, ultrasound is still considered a primary adjunct. Given the dangers and adverse effects of PAS, it is necessary to identify pertinent markers and validate indicators to improve prenatal diagnosis. This article summarizes the predictors regarding biomarkers, ultrasound indicators, and magnetic resonance imaging (MRI) features. In addition, we discuss the effectiveness of joint diagnosis and the most recent research on PAS. In particular, we focus on (a) posterior placental implantation and (b) accreta after in vitro fertilization-embryo transfer, both of which have low diagnostic rates. At last, we graphically display the prenatal diagnostic indicators and each diagnostic performance.

Conservative surgical approach towards placenta accreta spectrum disorders for uterine preservation

OBJECTIVE

We previously described a technique for repair of the myometrial defect at repeat Caesarean section which increases residual myometrial thickness thereby potentially reducing future niche-related complications. Here we describe how this technique can be modified for use for placenta accreta spectrum disorders, in line with emerging evidence that this is more a disorder of myometrial deficiency than morbid adherence.

DESIGN

The surgical performance of peripartum hysterectomy was compared with that of the modified technique in all women having repeat Caesarean delivery for placenta accreta spectrum disorder in a tertiary unit in Singapore between December 2019 and October 2021.

METHODS

Modification of the original technique involved the systematic delivery of the placenta starting from its most posterior attachment after uterine exteriorization. This is followed by the identification, mobilization, and apposition of the boundaries of myometrial defects as described previously.

RESULTS

Ten women had Caesarean hysterectomy and ten had Caesarean section using the modified approach. Age and gestational age at delivery were similar for the two groups. Women in the modified technique group had had fewer prior Caesarean sections and had a lower body mass index. Operating time, estimated blood loss and need for transfusion were all lower in the myometrial repair group but without statistical significance. There were no visceral injuries in the repair group but there was one bladder injury in the hysterectomy group.

CONCLUSION

The modified approach provides an effective alternative to peripartum hysterectomy with favourable surgical profile and allows uterine conservation with restoration of myometrial thickness.