Three-dimensional ultrasound for evaluation of residual placental volume after conservative management of placenta accreta spectrum in a single tertiary center

Objective: To evaluate the residual placental volume and correlated factors using three-dimensional ultrasound (3D) in patients with placenta accreta spectrum (PAS) after conservative management. Materials and methods: From January 2005 to December 2023, we retrospectively reviewed patients with PAS who underwent prophylactic transcatheter arterial embolization and retained the placenta in situ. The residual placental volume was assessed using 3D ultrasound equipped with virtual organ computer-aided analysis. We determined the resorption rate of the residual placenta (RRRP) and analyzed correlated factors. Results: Eighteen patients with PAS were included. The mean RRRP was 152.64 ± 147.97 cm3/month. The median natural resorption time was 5.5 months. According to Spearman's correlation, only the initial placental volume was significantly associated with RRRP (p = 0.001, correlation coefficient = 0.701). Initial placental volume was not associated with postpartum hemorrhage, postpartum infection, resume of menstruation, subsequent pregnancy, or mean white blood cell count. Conclusion: 3D ultrasound is useful for measuring the volume of residual placenta. A larger initial placental volume was associated with a higher RRRP.