Neutrophil‑to‑Lymphocyte Ratio in Early Pregnancy as a Predictor of Preeclampsia: A Cohort Study

Background: Preeclampsia (PE) affects up to 5–15% of pregnancies in India and contributes substantially to maternal-fetal morbidity. Its pathogenesis involves systemic inflammation and endothelial dysfunction. The neutrophil-to-lymphocyte ratio (NLR), a simple index of systemic inflammation, has been studied as a potential early predictor of PE. However, results have been inconsistent. We aimed to assess whether first-trimester NLR predicts subsequent development of PE in a prospective cohort of Indian women. Material and Methods: We enrolled 35 pregnant women (mean age 27.4±3.9 years) at 11–14 weeks’ gestation in a tertiary centre in India. Exclusion criteria included chronic hypertension, diabetes, renal or autoimmune disease, multiple gestation, and infections. Blood was drawn for complete blood count; NLR was calculated (neutrophil count/lymphocyte count). Participants were followed to delivery and classified as developing PE (new-onset hypertension ≥140/90 mmHg plus proteinuria after 20 weeks) or remaining normotensive. We compared baseline demographics and NLR between groups, and performed logistic regression and receiver-operating-characteristic (ROC) analysis. Statistical significance was set at p<0.05. Results: Six women (17%) developed PE and 29 remained normotensive. Baseline age, body mass index and parity did not differ significantly between groups. Mean first-trimester NLR was significantly higher in the future-PE group (3.25±0.55) than in normotensive controls (2.07±0.48; p<0.001) (Table 2). On ROC analysis (Figure 1), the area under the curve for NLR was 0.82 (95% CI 0.67–0.96), indicating good discrimination. An optimal NLR cut-off of ≈3.0 yielded 83% sensitivity and 79% specificity for predicting PE. In univariate logistic regression, each unit increase in NLR was associated with an odds ratio of 4.8 for PE (95% CI 1.5–15.0; p=0.007). Conclusion: In this cohort of 35 Indian women, elevated NLR in early pregnancy was strongly associated with later development of preeclampsia. First-trimester NLR showed reasonable predictive performance and could be a useful component of early screening. These findings support previous reports of higher early-pregnancy NLR in women who develop PE. Larger prospective studies should further define optimal cut-offs and assess NLR in combination with other markers for PE risk stratification.

Keywords: Preeclampsia, neutrophil-to-lymphocyte ratio, first trimester, prediction, cohort study.