Gestational ocular microvascular changes in healthy pregnancy: a longitudinal SS-OCTA study

This prospective longitudinal study investigated trimester-specific ocular microvascular changes in healthy pregnancy using swept-source optical coherence tomography angiography (SS-OCTA). Sixty pregnant women underwent SS-OCTA imaging during early (< 14 weeks), mid- (14–27 weeks), and late pregnancy (> 27 weeks). The study demonstrated: (1) A unique V-shaped trajectory in choroidal vessel density (CVD), with initial decline (86.91 ± 2.01% to 85.77 ± 2.87%, P < 0.001) followed by partial recovery in late pregnancy (85.87 ± 2.82%, P < 0.001 vs. mid-trimester), contrasting with progressive retinal vessel density (RVD) reduction (63.23 ± 3.96% to 58.76 ± 4.26%, P < 0.001); (2) Paradoxical optic nerve changes combining decreased vessel density (73.89 ± 4.37% to 69.48 ± 4.40%, P < 0.001) with increased retinal nerve fiber layer thickness (108.78 ± 10.63 μm to 111.30 ± 11.26 μm, P = 0.02); (3) Region-specific vulnerability showing most significant changes in the 1–3 mm retinal zone. These findings provide the first evidence of choroidal vascular adaptation during pregnancy and establish normative trimester-specific benchmarks. The study identifies distinct retinal-choroidal hemodynamic responses, offering new insights into ocular vascular physiology and creating a foundation for detecting pathological deviations in high-risk pregnancies. The choroidal recovery phenomenon may serve as a novel biomarker for circulatory adaptation monitoring.