Analysis of placentas containing different levels of TFPI and TF. Representative E15.5 placentas from a cross between a TFPI^–/–/low-TF male and a TFPI^+/–/mTF^+/–/hTF^+/o female. Macroscopic surface views of placentas are shown. (A) TFPI^+/–/mTF^+/–/hTF^+/o placentas. (B) TFPI^+/–/mTF^–/–/hTF^+/o placentas. (C) TFPI^–/–/mTF^–/–/hTF^+/o placentas. Blood pools in panels B and C are shown with arrows. Histologic analysis (H&E) of the placentas is shown. Original magnification, × 40.