Monocyte-to-HDL Ratio in Early Pregnancy as a Biomarker for Preeclampsia Risk Stratification

Background Preeclampsia (PE) remains a leading cause of maternal and perinatal morbidity and mortality worldwide. Early identification of women at risk is essential for timely preventive interventions, yet current screening approaches have limitations in accessibility and predictive performance. The monocyte-to-high-density lipoprotein cholesterol ratio (MHR), a composite marker of inflammation and oxidative stress, has emerged as a potential biomarker but has not been adequately studied for early pregnancy prediction of PE. Methods This retrospective cohort study ultimately included 11,895 pregnant women in China who underwent routine first-trimester blood testing before 14 weeks’ gestation. The association between ln-transformed MHR (ln[MHR]) and subsequent development of PE was assessed using multivariable logistic regression, restricted cubic spline models, and two-piecewise linear regression, adjusting for maternal age, body mass index (BMI), parity, in vitro fertilization (IVF) conception, and multifetal gestation. Subgroup analyses were performed to evaluate potential effect modification. Results First-trimester ln(MHR) was significantly higher in women who later developed PE (P < 0.001). In multivariable analysis, elevated ln(MHR) was independently associated with increased risk of PE (adjusted OR: 1.80; 95% CI: 1.38–2.36; P < 0.001). A dose-response relationship was observed across ln(MHR) quartiles, with women in the highest quartile having a 67% increased risk compared to the lowest (adjusted OR: 1.67; 95% CI: 1.25–2.23; P < 0.001). Restricted cubic spline analysis indicated a near-linear association, and a two-piecewise model identified a threshold at ln(MHR) = − 0.97 above which risk increased sharply. The association remained consistent across subgroups defined by maternal age, BMI, parity, IVF conception and multifetal gestation (P for interaction > 0.05 for all). Conclusion Elevated first-trimester ln(MHR) was independently associated with subsequent PE, showing dose-dependent and threshold effects. These findings suggest that MHR may serve as a simple, accessible biomarker for early risk stratification of PE in prenatal care.