The Placenta and Neurodevelopment in Preterm Newborns

Abstract

In caring for preterm neonates, a major challenge lies in understanding the contributors to brain dysmaturation and injury, both of which serve as precursors to childhood neurodevelopmental impairment. In addition to the various adverse exposures that the preterm newborn encounters in postnatal life, the placental antecedents of preterm delivery, in and of themselves, may affect brain dysmaturation and injury. The abnormal placenta is a frequent complication of pregnancy, and placental pathologies, such as placental insufficiency and acute chorioamnionitis, often precede preterm birth. Placental insufficiency is the principal cause of fetal growth restriction and acts via chronic fetal hypoxia. During fetal hypoxia, cardiac output redistribution to the brain represents an important fetal adaptive response; however, vascular sparing of the brain does not ensure normal brain growth. Early fetal growth restriction, which is associated with a hypermature and malperfused placenta, results in neurodevelopmental impairment independent of the duration of gestation in preterm newborns. Acute chorioamnionitis is characterized by infiltration of the placenta by immune cells and often results from infection that induces an inflammatory response. Chorioamnionitis can lead to the fetal inflammatory response syndrome and preterm labor, and thus can add to subsequent neonatal brain injury. Placental health should be assessed in understanding the origins of preterm brain dysmaturation and injury, and subsequent neurodevelopmental impairment.