Assessment of Oxidative Stress Biomarkers among Pregnant Women with Hypertensive Disorders in Osun State, Nigeria.

Abstract

Background: Hypertension in pregnancy, particularly pre-eclampsia and eclampsia, is a major cause of maternal and foetal morbidity and mortality in Nigeria. Oxidative stress, resulting from an imbalance between reactive oxygen species and antioxidant defences, is increasingly implicated in their pathophysiology, yet data on disease severity across Nigerian populations remain limited. This study assessed oxidative stress and antioxidant profiles among normotensive, pre-eclamptic, and eclamptic pregnant women. Methods: This cross-sectional study enrolled 210 pregnant women (≥20 weeks’ gestation) attending antenatal clinics in Osun State, Nigeria, comprising 70 normotensive controls, 70 women with preeclampsia, and 70 with eclampsia. Blood samples were analysed using standard biochemical methods to measure malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and total antioxidant capacity (TAC). Group differences were assessed using one-way ANOVA, and Pearson correlation was used to evaluate associations with blood pressure (p < 0.05). Results: MDA levels increased progressively from normotensive pregnancy (3.87 ± 0.94 µmol/L) to pre-eclampsia (6.52 ± 1.15 µmol/L) and eclampsia (8.26 ± 1.48 µmol/L; p < 0.001). Conversely, SOD, CAT, GPx, and TAC declined significantly across groups, with the lowest values observed in eclampsia (all p < 0.001). A graded oxidative imbalance was evident from mild pre-eclampsia to eclampsia. MDA correlated negatively with SOD (r = −0.68), CAT (r = −0.60), GPx (r = −0.63), and TAC (r = −0.71), and positively with systolic (r = 0.62) and diastolic blood pressure (r = 0.58) (all p < 0.001). Conclusion: Pre-eclampsia and eclampsia are associated with a progressive increase in oxidative stress and depletion of antioxidant defences. The strong associations between oxidative markers and blood pressure support oxidative stress as a central mechanism in hypertensive disorders of pregnancy and highlight its potential value for assessing disease severity in resource-limited settings.