This study will aim to investigate whether systemic inflammatory markers-especially the neutrophil-to-lymphocyte ratio (NLR)-obtained from preoperative complete blood counts can predict the development of post-dural puncture headache (PDPH) in obstetric patients undergoing cesarean section under spinal anesthesia.

Inclusion Criteria:

• Women aged 18 years or older
• Underwent elective or emergency cesarean section under spinal anesthesia
• Had complete preoperative complete blood count (CBC) data available
• No known hematological or inflammatory disease
• No intraoperative complications recorded
• Medical records accessible for postoperative follow-up regarding PDPH symptoms

Exclusion Criteria:

• Age under 18
• Absence of preoperative complete blood count data
• Presence of hematologic malignancy, active infection, autoimmune disease, or immunosuppressive therapy
• Platelet count <150,000/mm³ or INR >1.5
• Incomplete or missing medical records

Only female participants were included, as the study population consisted of obstetric patients undergoing cesarean section under spinal anesthesia.

The study population consists of obstetric patients who underwent cesarean section under spinal anesthesia between January 2020 and December 2024 at a single tertiary center.