Clinicopathological characteristics of miscarriages featuring placental massive perivillous fibrin deposition

Introduction: Massive perivillous fibrin deposition (MPFD) is frequently associated with detrimental pregnancy outcomes, and extensive perivillous fibrin deposition results in severe placental dysfunction and loss of maternofetal interface. Unfortunately, the fundamental pathogenesis of MPFD remains unknown, and systematic analyses of MPFD in miscarriage is lacking. We analyzed the frequency and clinicopathological characteristics of MPFD in first trimester miscarriages. Methods: We analyzed a consecutive series of miscarriages (n = 582) gathered between March 2012 and June 2016. MPFD was classified as fibrin-type (f-MPFD) and matrix-type (m-MPFD) by immunostaining for fibrin and collagen type IV. The control group consisted of miscarriage cases (MC, n = 18) that were matched to f-MPFD with normal chromosome (f-MPFD-nc) for number of previous miscarriages and placental chromosomal status. Results: MPFD was identified in 2.7% of miscarriages. f-MPFD was associated with recurrent abortions. Compared with miscarriages without fibrin deposition, MPFD cases had higher proportion of those with normal placental chromosome (69.2% vs. 27.4%, P < 0.005) and higher frequency of villous syncytiotrophoblast C4d deposition (73.3% vs. 33.9%, P < 0.005). All C4d(+) f-MPFD patients had more than three recurrent miscarriages, whereas C4d(-) f-MPFD patients had no history of recurrent miscarriage (P < 0.05). Patients with f-MPFD-nc had significantly higher HLA PRA immunopositivity rate than did MC patients (P = 0.005). Discussion: MPFD was more common in miscarriages than in preterm and term pregnancies. Placental massive fibrin-type fibrinoid deposition and villous C4d immunoreactivity were associated with recurrent miscarriage.