The human decidua as a passage-way for trophoblast invasion: A review

Abstract

Summary Decidual changes in the endometrial stroma are regarded as highly important for placentation. During placental development the bulk of glandular tissue shows lateral displacement, and a progressive thinning of decidua occurs. While there is no evidence for a direct cytolytic action of trophoblast on maternal cells, local vascular disturbances may lead to superficial necrotic streaks of decidua which may subsequently regress or become incorporated into Nitabuch's layer or placental septa. Although in several rodent species decidua may act as a barrier to trophoblast invasion, which is gradually removed human where numerous trophoblastic cells invade the inner myometrium. Impairment of decidual function may be responsible for cases of placenta accreta, but cannot be invoked to explain histopathological defects in preeclampsia. In this case shallow invasion of spiral arteries is well documented, but there is no hard evidence of limited invasion of interstitial trophoblast. For proper understanding trophoblast-uterine interactions, attention of investigators should be broadened to include trophoblastmyometrial interactions.