TrophoblastsChorionic VilliPlacentaPregnancy Trimester, FirstPregnancyPregnancy Trimester, ThirdPlacenta DiseasesPre-EclampsiaFetal Growth RetardationCells, CulturedImmunohistochemistryPlacentationChoriocarcinomaDeciduaEmbryo ImplantationPregnancy ProteinsHLA-G AntigensGiant CellsBlastocystChorionMaternal-Fetal ExchangePlacental Lactogen