Placental Vascular Malperfusion, Perinatal Death and Neonatal Brain Injury: A Mechanism-Based Narrative Review with...

Background/Objectives: Placental vascular malperfusion, on both the maternal (MVM) and fetal (FVM) side, is a key mechanism linking hypertensive disorders of pregnancy, fetal growth restriction (FGR), stillbirth, preterm neonatal death and neonatal encephalopathy. Nevertheless, clinical use and medico-legal interpretation of placental findings remain inconsistent. To summarize recent evidence on the relationship between placental vascular malperfusion, perinatal mortality and neonatal brain injury, integrating standardized placental pathology with Doppler and angiogenic biomarkers, and to outline the main medico-legal implications. Methods: A PubMed search using the string "((placenta OR placental pathology) AND (stillbirth OR fetal death) AND (maternal vascular malperfusion OR fetal vascular malperfusion))" yielded 118 records. After excluding reviews, meta-analyses, case reports (except one illustrative SARS-CoV-2 placentitis case), non-human studies and papers without original histopathology, 33 studies were included: observational cohorts and case-control studies with standardized placental assessment, autopsy series, biomarker/Doppler cohorts, mechanistic work, one randomized trial protocol and a small number of focused clinical commentaries. Results: Across these studies, MVM emerges as the dominant placental lesion in pre-eclampsia, FGR and a large proportion of stillbirths, especially in early-onset disease and in association with maternal hypertension. FVM is strongly linked to stillbirth and term neonatal encephalopathy, and specific combinations of MVM, FVM and inflammatory lesions correspond to distinct patterns of brain injury. Large population-based cohorts confirm that maternal hypertensive disorders and placental malperfusion are major upstream causes of intrauterine hypoxia and preterm neonatal death. Doppler velocimetry and angiogenic biomarkers (PlGF, sFlt-1 and their ratio) are strongly associated with an increased likelihood of underlying MVM and adverse neonatal outcomes, although their predictive performance remains probabilistic and context-dependent rather than diagnostic. Mechanistic studies suggest roles for placental genomic instability and altered decidual immunity in defective placentation. Conclusions: Maternal and fetal vascular malperfusion represent converging pathways to FGR, stillbirth, preterm neonatal death and neonatal encephalopathy. Routine, standardized placental examination, interpreted together with Doppler and biomarker data, substantially improves causal attribution and timing of injury, with direct consequences for counselling, prevention and medico-legal assessment.