Association of Preoperative Neutrophil-to-Lymphocyte Ratio With Post-Dural Puncture Headache After Cesarean Delivery.

BACKGROUND Post-dural puncture headache (PDPH) is a common complication of spinal anesthesia in cesarean delivery. While demographic and procedural factors are well recognized, the role of systemic inflammatory indices in pregnant women has not been clearly defined. MATERIAL AND METHODS This retrospective cohort study included 821 pregnant women who underwent elective cesarean delivery under spinal anesthesia between January 2020 and December 2024. PDPH was diagnosed using the ICHD-3 criteria. Preoperative neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), and systemic inflammation response index (SIRI) were evaluated using correlation, logistic regression, and receiver operating characteristic (ROC) analyses. RESULTS PDPH occurred in 133 patients (16.2%). Median NLR values were lower in the PDPH group compared with controls (2.63 vs 3.82, P<0.001). NLR showed a moderate negative correlation with PDPH (ρ=-0.41, P<0.001). After adjustment for potential confounders, only NLR showed a significant association with PDPH (OR 0.51, 95% CI 0.39-0.66, P<0.001). ROC analysis demonstrated a moderate discriminatory performance (AUC 0.76), and a cutoff of ≤3.14 achieved 88.7% sensitivity and 92.1% negative predictive value. CONCLUSIONS Lower preoperative NLR values showed an association with PDPH after cesarean delivery under spinal anesthesia. Identification of a clinically relevant cutoff suggests that NLR may be a practical biomarker for perioperative risk assessment in obstetric anesthesia. Further prospective, multicenter studies are needed to confirm these findings.