Elevated intraocular pressure and ocular perfusion pressure in gestational hypertension: a cross-sectional study in a Chinese population

Gestational hypertension (GH) is associated with systemic vascular dysfunction, yet its impact on intraocular pressure (IOP) and ocular perfusion pressure (OPP) remains incompletely characterized, particularly in Chinese populations. We investigated IOP and OPP differences between women with GH and normal pregnancy, and explored the influence of parity. In this single-centre, cross-sectional study, 50 normal pregnant women and 42 with GH were enrolled between October 2022 and October 2023. IOP was measured bilaterally by non-contact tonometry. OPP was calculated as 2/3 × mean arterial pressure (MAP) − mean IOP. Group differences were assessed by the Mann-Whitney U test. Multiple linear regression identified independent predictors of IOP. Because body mass index (BMI) and parity were not recorded in the prospective cohort, secondary analyses of these variables used a separate historical normal-pregnancy cohort assembled under the same protocol and are therefore exploratory. A prespecified sensitivity analysis restricted to third-trimester participants addressed the between-group difference in gestational age. Mean IOP was significantly higher in GH than in normal pregnancy (18.35 ± 2.72 vs. 16.81 ± 2.26 mmHg; p = 0.004, rank-biserial r = 0.35). OPP was markedly elevated in GH (53.45 ± 4.65 vs. 37.44 ± 4.32 mmHg; p < 0.001, r = 0.99); because OPP is calculated from MAP, this difference is largely a mathematical consequence of the higher MAP that defines GH. BMI (available only from the historical cohort) was comparable with the GH group ( p = 0.551) and was not associated with IOP; this exploratory analysis does not exclude BMI as a confounder in the prospective comparison. Within the normal pregnancy cohort, primiparous women had higher IOP than multiparous women (17.01 ± 2.55 vs. 15.77 ± 2.30 mmHg; p = 0.021). In an exploratory multivariable regression (prospective GH group combined with the historical cohort), primiparous status was the only significant predictor of IOP (β = 1.29; 95% CI 0.27–2.30; p = 0.013), whereas GH status was not independently significant after adjustment ( p = 0.294). When the primary comparison was restricted to third-trimester participants, the IOP difference attenuated to a non-significant trend (16.83 vs. 18.30 mmHg; p = 0.059), whereas the OPP difference remained highly significant ( p < 0.001). In this cross-sectional sample, GH was associated with higher IOP and markedly higher calculated OPP than normal pregnancy; the OPP difference is largely driven by the higher MAP that defines GH, and the IOP difference was attenuated after accounting for gestational age. Exploratory analyses suggested that parity may influence IOP. These preliminary findings indicate that ocular haemodynamic changes in GH warrant further study, but prospective gestational-age-matched studies are required before routine ocular monitoring can be recommended.