Oxidative Stress and Thyroid Dysfunction as Predictors of Bad Obstetric History: A Case-Control Study from South India

Abstract Background Emerging evidence suggests that oxidative stress and thyroid dysfunction are associated with adverse pregnancy outcomes; however, their underlying mechanisms in bad obstetric history (BOH) remain unclear and may vary across populations. Aim This study evaluated the role of oxidative stress and thyroid dysfunction as independent predictors of BOH among South Indian women. Methods This case-control study enrolled 120 women with documented BOH and 120 age-matched controls. Serum malondialdehyde (MDA) was measured by ELISA as a marker of oxidative stress. Thyroid hormones (T3, T4, and TSH) were assessed using chemiluminescence immunoassay. Data were analyzed using Mann–Whitney U and Chi-square tests, followed by Pearson correlation, logistic regression, and ROC analyses. Results Women with BOH had significantly higher MDA and TSH levels and lower T3 and T4 levels than controls (all p  < 0.001). Multivariable logistic regression identified MDA (OR = 6.32, p  < 0.001), TSH (OR = 6.258, p  = 0.023), and T4 (OR = 2.241, p  = 0.045) as independent predictors of BOH. MDA (AUC = 0.986) and TSH (AUC = 0.897) demonstrated excellent and good predictive performance, respectively. Conclusion Oxidative stress and thyroid dysfunction are significantly associated with BOH in South Indian women. Serum MDA and TSH emerged as independent predictors with high predictive accuracy, supporting their potential utility for early risk stratification.