The eye as a window to placental health: retinal imaging as a novel biomarker for preeclampsia and fetal growth restriction.

Preeclampsia (PE) and fetal growth restriction (FGR) are major causes of maternal and perinatal morbidity. The retina, an accessible and non-invasive window to the systemic microcirculation, offers quantitative biomarkers of maternal endothelial dysfunction that are central to development of PE and FGR. Advances in optical coherence tomography and Optical Coherence Tomography Angiography (OCTA) enable rapid, contrast-free measurement of vessel density, foveal avascular zone geometry and layer-specific thickness with high reproducibility. Emerging studies report reduced superficial capillary plexus density and hypertensive retinopathy signs in hypertensive disorders of pregnancy, with larger effects in early-onset PE. However, evidence remains mostly cross-sectional, heterogeneous and limited by small sample size. We describe potential clinical applications including targeted screening of high-risk women, enhancement of existing risk prediction models, longitudinal disease monitoring and assessment of treatment response. A staged research agenda is proposed, as following: (1) harmonized acquisition and quality standards; (2) prospective, trimester-specific cohorts linking retinal metrics to maternal and perinatal outcomes; (3) conducting mechanistic substudies to relate retinal signatures to systemic hemodynamics; 4) performing implementation trials to evaluate feasibility, equity and the impact on maternal and perinatal outcomes.