Depletion and proteolysis of FV and enhanced plasmin generation in AOC. (A) FV activity in nonbleeding pregnant controls, AOC, and severe PPH without AOC. (B) FV degradation was analyzed by western blotting. Samples were run under reducing conditions and FV detected by a monoclonal antibody directed to the heavy chain. Two patients with AOC are found to have reduced or undetectable FV compared with PNP and a nonbleeding pregnant control at the time of elective cesarean delivery (illustrated in green). The positive controls are PNP plus activated protein C (aPC) for 15 minutes or PNP plus plasmin for 10 minutes; in both cases, the FV is reduced. (C) Plasmin generation was analyzed in the plasma from the nonbleeding pregnant controls, AOC, and severe PPH without AOC. (D) The relationship between D-dimer and tPA-initiated plasmin generation capacity in all cases of PPH, including AOC and non-AOC cases. (E) The relationship between plasmin generation capacity and the amount of fragment D in the blood of a single patient with AOC at different time points who is described in the case report. Fibrinogen degradation in these patient samples is found in Figure 2C.