22 cases with conservative management
Three cases were delivered via caesarean section. The median RPOC diameter was 46 mm, with five cases exceeding 100 mm (Figure 1B). Seventeen cases had blood flow in RPOC on contrast-enhanced computed tomography (CT), contrast-enhanced magnetic resonance imaging (MRI), or Doppler ultrasound (Figure S1). Three cases had no blood flow, and two were not evaluable.
12 cases experienced heavy bleeding and nine cases required haemostasis through UAE. Six of the 12 cases had unprovoked bleeding. The remaining six cases experienced heavy bleeding during placental removal trial. In five cases, pulling on the detached placenta caused major bleeding. Dilatation and curettage (D&C) in one case led to heavy bleeding. Three cases underwent UAE, and three required blood transfusion. Even though the contrast-enhanced MRI did not show any blood flow, case 31 had heavy bleeding due to placental traction.
Three of the 22 cases had infection, all of which were cured with antibiotics. Case 20 underwent MROP on postpartum day 7 and showed signs of infection on postpartum day 15. Eight cases had no complications, such as bleeding or infection, and three of them were delivered via caesarean section. RPOC resolved spontaneously in 17 of 22 cases (77%) without surgical intervention, and the median time from delivery to resolution was 130 days. There was no difference between heavy (n=12) and light (n=9) bleeding cases in terms of RPOC diameter at diagnosis, blood flow on CT or MRI, and the time from delivery to resolution of RPOC (Table S1).
Regarding the timing, heavy bleeding occurred within 60 days postpartum. Blood transfusion was required within 60 days postpartum, and UAE required within 30 days postpartum. Infection occurred within 30 days postpartum (Figures 2A-D). Heavy bleeding, UAE, blood transfusion, and infection occurred within 40, 40, 20, and 30 days postpartum, respectively, in 16 cases, excluding six patients with haemorrhage in placental removal trial (Figures 2E-H). RPOC disappeared in approximately half of the cases at 100 days postpartum, and in 80% after 1 year postpartum. RPOC resolved spontaneously except in all except five cases, in which it was surgically removed (Figure 3).