Placental hypoxic overlap lesions: A clinicoplacental correlation

Aim This retrospective analysis is aimed to study clinical and placental associations of placental acute, chronic, and acute‐on‐chronic (overlap) hypoxic lesions. Material and Methods Frequencies of 32 clinical (maternal and fetal) and 47 placental (gross and microscopic) phenotypes were compared by the Yates χ2 with the Holm–Bonferroni correction among consecutive placentas from 2831 ≥16‐week gestations: 778 placentas with chronic hypoxic lesion(s) (diffuse patterns of hypoxic placental injury, chorangiosis, excessive extravillous trophoblasts, microscopic chorionic pseudocysts, clusters of decidual multinucleate trophoblasts), 481 placentas with acute hypoxic lesion(s) (infarction, intravillous hemorrhage, deep meconium penetration, membrane laminar necrosis), 585 placentas with hypoxic overlap lesion(s) (coexisting at least one lesion from each of the above groups), and 987 placentas without placental hypoxic lesions, adjusted for gestational age. Results The control group was dominated by premature rupture of membranes, inflammatory pattern of placental injury, and poor prenatal care. The fetal and placental hypoxic patterns were associated not only with increased frequency of clinical hypoxia‐associated conditions, but also abnormal umbilical cord coiling, intervillous thrombi, retroplacental hematomas, and placental features of fetal thrombotic vasculopathy, particularly in association with hypoxic overlap lesions. Conclusion Placental hypoxic overlap lesions are associated with clinical complications of pregnancy and predispose to thrombotic lesions, some most likely stasis‐induced.