Invasión trofoblástica en el embarazo normal (II): Placentación profunda (Trophoblastic invasion in normal pregnancy (II): Deep placentation)

Abstract

Deep placentation in human pregnancy is done by deep invasion of the placental bed by the extravillous trophoblast, involving the decidua and the inner (junctional zone) myometrium. Interstitial invasion of the stroma and endovascular trophoblast invasion of the spiral arteries both occur. Deep endovascular trophoblast invasion into the myometrial segments of spiral arteries is important for proper placental functioning. Decidua-associated vascular remodeling, which includes swelling and disorganization of the vascular smooth muscle, occurs during a period of rising placental oxygen. This early remodeling step may accommodate the progressively increasing maternal blood flow to the developing placenta. The subsequent trophoblast-associated remodeling step enhances and stabilizes the widening of the vessels, whereas the vascular smooth muscle and elastic lamina are replaced by a fibrinoid matrix with embedded trophoblast

Keywords

• Trophoblast invasion
• spiral arteries
• placental bed
• vascular remodeling