Fig. 1.

PGF Expression During Human Preimplantation Development. PGF is expressed by the Oocyte, Zygote, Two-cell Embryo and, after Zygotic Genome Activation, by the Morula and Blastocyst. At the window of implantation, hatched Blastocysts will show one of three patterns for PGF expression. Normal F1: In Normal pregnancies – Normal Expression of PGF on ICM and in Trophoblast PE-F1 Model #1 (Classic PE): Low PGF in Trophoblast and thus in maternal plasma over gestation but PGF levels are normal in ICM and its derivative tissues (includes membranes and embryo/fetus) PE-F1 Model #2 (Our hypothesis): Low PGF in both Trophoblast and thus in maternal plasma over gestation, and PGF levels are low in ICM and its derivative tissues (includes membranes and embryo/fetus) Abbreviations: PGF, placental growth factor; PE, preeclampsia; ICM, inner cell mass.