Exploring Retinal Microvascular Changes as Predictors of Late Pregnancy Complications

Abstract

Purpose : Cardiovascular changes are expected during pregnancy, but inadequate vascular adaptation or systemic microvascular dysfunction can result in complications in the later stages of gestation. Currently, there is a need for biomarkers to identify and monitor pregnant women at risk during this period. This pilot study shows the potential usefulness of retinal imaging as a novel source of biomarkers in evaluating maternal vascular responses and placental insufficiency.

Methods : We recruited 22 women between 34 and 38 weeks' gestation. We identified cases (n=11, mean age 33.8 ± SD 5.7 years) as pregnancies complicated by fetal growth restriction or preeclampsia, and controls (n=11, mean age 33.6 ± SD 5.4 years) as pregnancies without complications. We performed retinal imaging of both eyes using optical coherence tomography (OCT), OCT-angiography (OCT-A), and scanning laser ophthalmoscopy (SLO). We calculated choroidal thickness, area, and volume using fovea-centered OCT scans. We computed vessel density, foveal avascular zone area (FAZ), branching points, flow index, radius and tortuosity of large vessels using the superficial vascular complex captured in the 3x3 mm² OCT-A scans. Fractal dimension as a measure of the branching complexity of the retinal vasculature was assessed using SLO images. Finally, we compared how these retinal vascular measurements changed between groups, separately for the right (OD) and left (OS) eye.

Results : Our results indicate increases in choroidal area (OD: 1.84mm²±0.44 vs 1.54mm²±0.47, OS: 1.65mm²±0.34 vs 1.63mm²±0.55) and FAZ area (OD: 0.43mm²±0.27 vs 0.32mm²±0.12, OS: 0.43mm²±0.25 vs 0.33mm²±0.10), and reductions in large vessel radius (OD: 15.81µm±1.70 vs 16.19µm±1.22, OS: 15.31µm±1.02 vs 15.73µm±0.73) and fractal dimension (OD: 1.54±0.02 vs 1.55±0.03, OS: 1.54±0.02 vs 1.56±0.02), in cases compared to controls.

Conclusions : Our preliminary findings, although not statistically significant, suggest that retinal imaging could be a potential source of biomarkers that help identify individuals at risk during late pregnancy. In future research, we will capture retinal images from more individuals, to overcome the limitation of the small sample size, and at various time points throughout gestation to validate the effectiveness of retinal vascular metrics for predicting pregnancy complications.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

OCT, SLO, and OCT-A scans, choroid detection, vessel segmentation, and FAZ detection.