VP46.30: Placental thickness as a screening tool for placenta accreta spectrum disorder in women with placenta previa

To evaluate the association of placental thickness with placenta accreta spectrum (PAS) disorder and its utility in screening women with placenta previa (PP). In this IRB-approved, retrospective study, ultrasound (US) reports were retrospectively queried for keyword previa. In patients with multiple exams, US performed closest to mid-gestation were included. Three measurements were performed at the thickest portion of the placenta on longitudinal plane in the lower uterine segment as seen on transabdominal images. Operative reports and surgical pathology results were used as the reference standard. Average thickness was compared between the two groups of patients, using paired t-tests. 65 patients with PP were included: 36 cases of PAS disorder and 29 patients without PAS disorder. 36/36 (100%) patients with PAS and 17/29 (58.6%) patients of non-PAS group had history of prior Caesarean section. The average placenta thickness was 4.3cm (range: 1.8–7.8cm) for PAS group and 3.1cm (range: 0.6-6.0cm) for non-PAS group (p < 0.001). The average placenta thickness for patients who had history of prior Caesarean section without PAS was 3.1 (+/- 1.1)cm, which was statistically different from patients who had history of prior Caesarean section and with PAS diagnosis (p < 0.01). All placenta measuring more than 6cm in thickness were abnormal. Among women with PP, increased placenta thickness at lower uterine segment correlates with placenta accreta spectrum disorder and can be used to screen women for PAS disorder. Placental thickness was greater in patients with PAS disorder both with and without history of prior Caesarean section. Greater placental thickness was noted in patients with PAS with myometrial invasion compared to placenta accreta only. Supporting information can be found in the online version of this abstract Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.