Prenatal diagnosis of placenta accreta spectrum

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.

Management and Outcome of Women with Placenta Accreta Spectrum and Treatment with Uterine Artery Embolization

BACKGROUND

Placenta accreta spectrum (PAS) disorders are a continuum of placental pathologies with increased risk for hemorrhage, blood transfusion and maternal morbidity. Uterine artery embolization (UAE) is a safe approach to the standardization of complex PAS cases. The aim of this study is to analyze anemia and transfusion rate, outcome and anesthesiological management of women who underwent caesarean delivery with subsequent UAE for the management of PAS.

MATERIAL AND METHODS

This retrospective observational study included all pregnant women admitted to the University Hospital Frankfurt between January 2012 and September 2023, with a diagnosis of PAS who underwent a two-step surgical approach for delivery and placenta removal. Primary procedure included cesarean delivery with subsequent UAE, secondary procedure included placenta removal after a minim of five weeks via curettage or HE. Maternal characteristics, anesthesiological management, complications, anemia rate, blood loss and administration of blood products were analyzed.

RESULTS

In total, 17 women with PAS were included in this study. Of these, 5.9% had placenta increta and 94.1% had placenta percreta. Median blood loss was 300 (200-600) mL during primary procedure and 3600 (450-5500) mL during secondary procedure. In total, 11.8% and 62.5% of women received red blood cell transfusion during the primary and secondary procedures, respectively. After primary procedure, postpartum anemia rate was 76.5%. The HE rate was 64.7%. Regional anesthesia was used in 88.2% during primary procedure.

CONCLUSION

The embolization of the uterine artery for women diagnosed with PAS is safe. Anemia management and the implementation of blood conservation strategies are crucial in women undergoing UAE for the management of PAS.

Comparison of maternal outcomes and clinical characteristics of prenatally vs nonprenatally diagnosed placenta accreta spectrum: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compare maternal outcomes of prenatally and nonprenatally diagnosed placenta accreta spectrum.

DATA SOURCES

A systematic literature search was performed in PubMed, the Cochrane database, and Web of Science until November 28, 2022.

STUDY ELIGIBILITY CRITERIA

Studies comparing the clinical presentation of prenatally and nonprenatally diagnosed placenta accreta spectrum were included. The primary outcomes were emergent cesarean delivery, hysterectomy, blood loss volume, number of transfused blood product units, urological injury, coagulopathy, reoperation, intensive care unit admission, and maternal death. In addition, the pooled mean values for blood loss volume and the number of transfused blood product units were calculated. The secondary outcomes included maternal age, gestational age at birth, nulliparity, previous cesarean delivery, previous uterine procedure, assisted reproductive technology, placenta increta and percreta, and placenta previa.

METHODS

Study screening was performed after duplicates were identified and removed. The quality of each study and the publication bias were assessed. Forest plots and I2 statistics were calculated for each study outcome for each group. The main analysis was a random-effects analysis.

RESULTS

Overall, 415 abstracts and 157 full-text studies were evaluated. Moreover, 31 studies were analyzed. Prenatally diagnosed placenta accreta spectrum was associated with a significantly lower rate of emergency cesarean delivery (odds ratio, 0.37; 95% confidence interval, 0.21-0.67), higher hysterectomy rate (odds ratio, 1.98; 95% confidence interval, 1.02-3.83), lower blood loss volume (mean difference, -0.65; 95% confidence interval, -1.17 to -0.13), and lower number of transfused red blood cell units (mean difference, -1.96; 95% confidence interval, -3.25 to -0.68) compared with nonprenatally diagnosed placenta accreta spectrum. The pooled mean values for blood loss volume and the number of transfused blood product units tended to be lower in the prenatally diagnosed placenta accreta spectrum groups than in the nonprenatally diagnosed placenta accreta spectrum groups. Nulliparity (odds ratio, 0.14; 95% confidence interval, 0.10-0.20), previous cesarean delivery (odds ratio, 6.81; 95% confidence interval, 4.12-11.25), assisted reproductive technology (odds ratio, 0.19; 95% confidence interval, 0.06-0.61), placenta increta and percreta (odds ratio, 3.97; 95% confidence interval, 2.24-7.03), and placenta previa (odds ratio, 6.81; 95% confidence interval, 4.12-11.25) showed statistical significance. No significant difference was found for the other outcomes.

CONCLUSION

Despite its severity, the positive effect of prenatally diagnosed placenta accreta spectrum on outcomes underscores the necessity of a prenatal diagnosis. In addition, the pooled mean values provide a preoperative preparation guideline.

Pathologically diagnosed placenta accreta spectrum without placenta previa: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to assess clinical characteristics related to pathologically proven placenta accreta spectrum without placenta previa.

DATA SOURCES

A literature search of PubMed, the Cochrane database, and Web of Science was performed from inception to September 7, 2022.

STUDY ELIGIBILITY CRITERIA

The primary outcomes were invasive placenta (including increta or percreta), blood loss, hysterectomy, and antenatal diagnosis. In addition, maternal age, assisted reproductive technology, previous cesarean delivery, and previous uterine procedures were investigated as potential risk factors. The inclusion criteria were studies evaluating the clinical presentation of pathologically diagnosed PAS without placenta previa.

METHODS

Study screening was conducted after duplicates were identified and removed. The quality of each study and the publication bias were assessed. Forest plots and I2 statistics were calculated for each study outcome for each group. The main analysis was a random-effects analysis.

RESULTS

Among 2598 studies that were initially retrieved, 5 were included in the review. With the exception of 1 study, 4 studies were included in the meta-analysis. This meta-analysis showed that placenta accreta spectrum without placenta previa was associated with less risk of invasive placenta (odds ratio, 0.24; 95% confidence interval, 0.16-0.37), blood loss (mean difference, -1.19; 95% confidence interval, -2.09 to -0.28) and hysterectomy (odds ratio, 0.11; 95% confidence interval, 0.02-0.53), and more difficult to diagnose prenatally (odds ratio, 0.13; 95% confidence interval, 0.04-0.45) than placenta accreta spectrum with placenta previa. In addition, assisted reproductive technology and a previous uterine procedure were strong risk factors for placenta accreta spectrum without placenta previa, whhereas previous cesarean delivery was a strong risk factor for placenta accreta spectrum with placenta previa.

CONCLUSION

The differences in clinical aspects of placenta accreta spectrum with and without placenta previa need to be understood.

Placenta accreta spectrum in major placenta previa diagnosed only by MRI: incidence, risk factors, and maternal morbidity

BACKGROUND

Antenatal assessment of maternal risk factors and imaging evaluation can help in diagnosis and treatment of placenta accreta spectrum (PAS) in major placenta previa (PP). Recent evidence suggests that magnetic resonance imaging (MRI) could complement ultrasonography (US) in the PAS diagnosis.

OBJECTIVES

Evaluate the incidence, risk factors, and maternal morbidity related to the MRI diagnosis of PAS in major PP.

DESIGN

A 10-year retrospective cohort study.

SETTING

Tertiary care hospital.

PATIENTS AND METHODS

We report on patients with major PP who had cesarean delivery in Abha Maternity and Children's Hospital (AMCH) over a 10-year period (2012-2021). They were evaluated with ultrasonography (US) and color Doppler for evidence of PAS. Antenatal MRI was ordered either to confirm the diagnosis (if equivocal US) or to assess the depth of invasion/extra-uterine extension (if definitive US).

MAIN OUTCOME MEASURES

Risk factors for PAS in major PP and maternal complications.

SAMPLE SIZE

299 patients RESULTS: Among 299 patients, MRI confirmed the PAS diagnosis in 91/299 (30.5%) patients. The independent risk factors for MRI diagnosis of PAS in major PP included only repeated cesarean sections and advanced maternal age. The commonest maternal morbidity in major PP with PAS was significantly excessive intraoperative bleeding.

CONCLUSION

MRI may be a valuable adjunct in the evaluation of PAS in major PP; as a complement, but not substitute US. MRI may be suitable in major PP/PAS patients who are older and have repeated cesarean deliveries with equivocal results or deep/extra-uterine extension on US.

LIMITATION

Single center, small sample size, lack of complete histopathological diagnosis.

CONFLICT OF INTEREST

None.

An update of diagnostic efficacy of ultrasound and magnetic resonance imaging in the diagnosis of clinically significant placenta accreta spectrum disorders

PURPOSE OF REVIEW

Systematic screening and diagnosis of placenta accreta spectrum disorder (PAS) either by ultrasound or magnetic resonance imaging (MRI) would allow referral of high-risk women to specialized multidisciplinary teams. We aimed to report recent findings regarding the diagnostic accuracy of ultrasound and magnetic resonance imaging in the diagnosis of PAS.

RECENT FINDINGS

Recent evidence from the literature shows that both ultrasound and MRI are good tests to identify PAS in high-risk populations. Ultrasound can also be used safely to guide management decisions, concentrating greater resources in patients with the higher risk of clinically significant PAS requiring complex peripartum management. Moreover, there are increasing data showing that routine contingent screening for PAS disorders based on the finding of a placenta implanted low in the uterine cavity and previous uterine surgery is effective in a public healthcare setting. A contingent screening strategy for PAS is feasible if placental location is routinely assessed during routine scans, and may even start from the first trimester of pregnancy.

SUMMARY

Ultrasound is an effective tool to screen pregnancies at high risk of PAS. In such pregnancies, ultrasound and MRI are effective imaging modalities for guiding management.

Unexpected uterine body placenta accreta spectrum with placenta previa in a subsequent pregnancy after uterine artery embolization: a case report

BACKGROUND

A subsequent pregnancy after uterine artery embolization (UAE) raises several concerns, one of which is placenta accreta spectrum (PAS). Placenta previa is the strongest risk factor for PAS, which is most likely to occur in the lower uterine segment. PAS without placenta previa (i.e., uterine body PAS) is considered relatively rare.

CASE PRESENTATION

A 35-year-old woman, gravida 2 para 1, had undergone UAE for postpartum hemorrhage due to uterine atony after vaginal delivery in her previous pregnancy. She developed placenta previa during her subsequent pregnancy and was therefore evaluated for PAS in the lower uterine segment. On the basis of examination findings, we considered PAS to be unlikely. During cesarean section, we found that the placenta was not detached from the uterine body, and the patient was determined to have uterine body PAS. Ultimately, a hysterectomy was performed.

CONCLUSIONS

PAS can occur in a subsequent pregnancy after UAE. When a subsequent pregnancy after UAE is accompanied by placenta previa, it is important to maintain a high index of suspicion of uterine body PAS without being misled by the presence of placenta previa.