Association of placental inflammation with fetomaternal hemorrhage and loss of placental mucin-1

Fetomaternal hemorrhage (FMH) poses an immediate risk to the fetus and, in case of Rhesus-immunization, to future pregnancies. Given that altered endothelial permeability is part of the pathophysiology of inflammation, in this study we investigated whether placental inflammatory processes like chorioamnionitis (ChoA) or preeclampsia (PE) lead to increased rates of FMH compared to the established risk factor of placenta previa (PP). Putative accompanying markers of trophoblastic damage were also explored. 40 patients (14 PE; 6 ChoA; 9 PP; 11 normal controls) were evaluated for FMH using a flowcytometric test kit, which is able to quantify FMH of 0.06% fetal cells. Placental tissue samples were immunostained for human placental lactogen (hPL), human chorionic gonadotropin (hCG), and mucin-1 (MUC1). MUC1 was evaluated as a potential serum marker of FMH. Patients with ChoA had a mean calculated FMH volume of 29 ml, compared to 4 ml in PE and 1 ml in PP and controls. MUC1 staining was reduced in PE and ChoA placenta samples, while elevated MUC1 serum concentration correlated positively with FMH. Diseases of placental inflammation are associated with FMH. Placental MUC1 staining is reduced and serum concentrations are increased in cases of FMH.