Diagnostic Accuracy of Placental Thickness in Lower Uterine Segment Measured by Ultrasound in Prediction of Placenta Accreta Spectrum in Patients with Placenta Previa. A Diagnostic Test Accuracy Study

Abstract

The aim of the study was to evaluate the association between placental thickness and placenta accreta spectrum (PAS) in patients with placenta previa. Materials and Methods: In this prospective study, 40 patients diagnosed with placenta previa were included. The maximum placental thickness in the lower uterine segment was obtained using a transabdominal scan. For the image to be deemed suitable, a midline sagittal section of the lower uterine segment (with the implanted placenta) and the cervical canal, with the intervening urinary bladder had been required. Intraoperative attendance was ensured for the detection of cases with spontaneous separation and cases with morbid adherence. All specimens removed were sent for histopathology to confirm PAS. The primary outcome of the study was to detect a threshold of placental thickness which can be used as a cut-off value in such screening test. The number of units of packed RBCs transfused during the operation and bladder injury were secondary measures of outcome. Results: Forty patients were included in the study; 20 patients were ultimately diagnosed with PAS while 20 patients did not have PAS. Mean placental thickness was significantly higher in the PAS patients compared with those with no invasive placentation (61.00 mm Vs 43.00 mm, P value 0.000). Using receiver operating characteristic (ROC) curve, a threshold placental thickness of 58mm was associated with 55% sensitivity, 90% specificity, 84.6% positive predictive value, and 66.7% negative predictive value. Multivariate logistic regression showed that placental thickness more than 58mm and having past history of more than three cesarean sections were independent risk factors for PAS among patients with placenta previa. Conclusion: Placental thickness in the lower uterine segment is increased in patients with placenta previa with PAS compared to those with no PAS. Such finding can be implemented into clinical practice by using placental thickness as a screening test for PAS in patients with placenta previa. ClinicalTrials.gov ID: NCT05500404.

Assessment of Placental Thickness in Cases with Placenta Previa as Marker for Intra and Postpartum Bleeding

“…Elmaraghy et al (9) showed that demographic data with age, parity, and number of prior CS being considerably higher in PAS patients, which is consistent with our results. Elmaraghy et al (9) concurs with our findings regarding blood transfusion and bladder injury, noting that there was no statistically significant difference in bladder injury between the two groups, but that blood requirements were significantly higher in the PAS group (increased placental thickness) when compared to cases with complete placental separation.…”

“…Elmaraghy et al (9) showed that demographic data with age, parity, and number of prior CS being considerably higher in PAS patients, which is consistent with our results. Elmaraghy et al (9) concurs with our findings regarding blood transfusion and bladder injury, noting that there was no statistically significant difference in bladder injury between the two groups, but that blood requirements were significantly higher in the PAS group (increased placental thickness) when compared to cases with complete placental separation. Our results are consistent with following study, using a transabdominal scan to assess the relationship between placental thickness and PAS in patients with placenta previa, Elmaraghy et al (9) carried out a prospective study that enrolled 40 patients with the diagnosis of placenta previa.…”

“…A hysterectomy was carried out in 42.5% (17/40) of cases, and bladder damage happened in 7.5% (3/40). There were no reports of ureteric or vascular injuries, nor of intestinal injuries (9) . Also, our finding agrees with Bhide et al (10) who measured placental thickness in women who had lowlying anterior placentas or major placenta previa on ultrasound.…”

Unexpected Dramatic Evolution of Placenta Increta: Case Report and Literature Review

“…As such, they can help plan for the safest delivery method and potential interventions [14,38]. In fact, ultrasound is the preferred method for diagnosing abnormally invasive placenta during pregnancy, and its diagnostic accuracy has been demonstrated to be reliable in both retrospective and prospective studies [39].…”

Risk factors of emergency cesarean section in pregnant women with severe placenta accreta spectrum: a retrospective cohort study

“…Placenta accreta spectrum is one of the most serious long-term complications of cesarean section, which may result in heavy postpartum hemorrhage. Due to endometrial damage, poor wound healing, and other factors, the villi and placenta are more likely to invade the muscle layer and even the serous layer in PAS patients who undergo cesarean section, resulting in placenta implantation and incomplete separation of the placenta during delivery (7)(8)(9). The rapture of the placental marginal sinus can result in severe bleeding during the operation, leading to severe complications such as disseminated intravascular coagulation, hysterectomy, infection, and even death (10)(11)(12)(13).…”