Placental vascular pathology as a mechanism of disease in pregnancy complications.

Inadequate placental development results in pregnancy complications. The extent and the degree of defective deep placentation may explain why a similar insult would result in different clinical presentations. The relative new categorization of the placental lesions, separating the non-infectious lesions into lesions that are consistent with maternal and fetal circulation abnormalities, and the infectious lesions into maternal and fetal inflammatory responses, provides us an additional tool to determine the placental maternal and fetal role in the various pregnancy complications. Placental vascular lesions are different in pregnancies complicated by preeclampsia (predominant maternal vascular supply lesions), by fetal growth restriction (FGR) (predominant fetal vascular supply lesions), and by preeclampsia with FGR (both maternal and fetal compartments are involved). Moreover, placental vascular lesions are also different in relation to gestational age at disease onset, as in early- and late-onset preeclampsia, FGR, Fetal death and preterm labor.