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PURPOSE: The eccentric implantation of pregnancies in the upper lateral aspect of the uterine cavity is poorly defined clinically. The aim of the current study was to investigate whether differentiating between uterine anomalies that can lead to cavitary distortion has implications for the management of these pregnancies. METHODS: Eight cases of first-trimester eccentric pregnancy implantation within the endometrial cavity (study group) were retrospectively identified. For each woman in the study group, 10 women identified as having a first-trimester concentric pregnancy implantation during the first-trimester US examination were retrieved from our database (control group). After delivery or pregnancy demise, the presence of uterine anomalies was assessed by a 3D-US examination in all patients. RESULTS: In the study group patients, an increased incidence of uterine anomalies (50.0% vs. 8.8%, p = 0.007) was found, compared to the controls. In the study group, the eccentric location persisted in half of the pregnancies (n = 4; 50%), whereas the other half migrated to a more centric location within the endometrial cavity (n = 4; 50%). The follow-up examination showed that all the early pregnancy demises occurred in cases where the pregnancy persisted at the eccentric location. Uterine malformations were also detected in all these cases. CONCLUSION: The data point to a significantly higher incidence of uterine anomalies in patients diagnosed with eccentric pregnancy implantation within the endometrial cavity. These results advocate for the value of differentiating between eccentric pregnancies in non-anomalous versus anomalous uteri.
RESUMO
OBJECTIVE: Clinical-sonographic scoring systems combining clinical features and ultrasound imaging markers have been proposed for the screening of placenta accreta spectrum, but their usefulness in different settings remains limited. This study aimed to assess and compare different clinical-sonographic score systems applied from mid-pregnancy for the prenatal evaluation of patients at risk of placenta accreta spectrum at birth. DATA SOURCES: PubMed/MEDLINE, Google Scholar, and Embase were searched between October 1982 and October 2022 to identify eligible studies. STUDY ELIGIBILITY CRITERIA: Observational studies providing data on the use of a combined clinical-ultrasound score system applied from mid-pregnancy for the prenatal evaluation of placenta accreta spectrum were included. METHODS: Study characteristics were evaluated by 2 independent reviewers using a predesigned protocol registered on PROSPERO (CRD42022332486). Heterogeneity among studies was analyzed with Cochran's Q-test and I2 statistics. Statistical heterogeneity was quantified by estimating the variance between the studies using I2 statistics. The area under the receiver operating characteristic curve of each score and their summary receiver operating characteristic curves were calculated with sensitivity and specificity, and the integrated score of the summaries of the receiver operating characteristic curves of all sonographic markers was calculated. Forest plots were used to develop the meta-analysis of each sonographic marker and for the integrated sonographic score. RESULTS: Of 1028 articles reviewed, 12 cohorts and 2 case-control studies including 1630 patients screened for placenta accreta spectrum by clinical-ultrasound scores met the eligibility criteria. A diagnosis of placenta accreta spectrum was reported in 602 (36.9%) cases, for which 547 (90.9%) intraoperative findings and/or histopathologic data were described. A wide variation was observed among the studies in reported sensitivities and specificities and in thresholds used for the identification of patients with a high probability of placenta accreta spectrum at birth. The summaries of the areas under the curve of the individual sonographic scores ranged from 0.85 (the lowest) for subplacental hypervascularity to 0.91 for placental location in the lower uterine segment, myometrial thinning, and placental lacunae and 0.95 for the loss of clear zone. Only 4 studies included placental bulging in their sonographic score system, and therefore no meta-analysis for this score was performed. The integrated summary of the areas under the curve was 0.83 (95% confidence interval, 79-0.86). Forest plot analysis revealed integrated sensitivities and specificities of 0.68 (95% confidence interval, 0.53-0.80) and 0.88 (95% confidence interval, 0.68-0.96), respectively. CONCLUSION: Clinical-sonographic score systems can contribute to the prenatal screening of patients at risk of placenta accreta spectrum at birth. Although we included multiple sonographic studies conducted during the mid-pregnancy period, standardized evaluation should be performed not only with strict ultrasound criteria for the placental position, mid third trimester gestational age at examination, and sonographic markers associated with PAS. Numeric sensitivities, specificities, NPVs, PPV, LR-, and LR+ should be recorded prospectively to assess their accuracy in different set-ups and PTP should be verified at delivery. The variables recommended for most predictive screening are: loss of clear zone underneath the placental bed, placentation in the LUS, and placenta lacunae.
