TrophoblastsPlacentaChoriocarcinomaPregnancyChorionic VilliPre-EclampsiaPregnancy Trimester, FirstDeciduaCells, CulturedChorionic GonadotropinRNA, MessengerGestational AgeCell DifferentiationPlacentationCell LineReverse Transcriptase Polymerase Chain ReactionImmunohistochemistryGene Expression Regulation, DevelopmentalGene ExpressionGene Expression RegulationApoptosisBlotting, WesternMolecular Sequence DataBase SequenceEmbryo ImplantationPregnancy ProteinsHLA-G Antigens