Some patients develop headache after spinal anesthesia used during cesarean section. This condition is called post-dural puncture headache (PDPH). Early identification of patients at risk may improve patient care.

This study evaluates whether optic nerve sheath diameter (ONSD), measured using a non-invasive bedside ocular ultrasound technique, can help predict the development of PDPH.

Participants undergoing cesarean section with spinal anesthesia will undergo ONSD measurements at predefined perioperative time points. Participants will be followed postoperatively for the occurrence of headache.

The findings may help improve early recognition and management of PDPH.

Post-dural puncture headache (PDPH) is a common complication after spinal anesthesia, particularly in patients undergoing cesarean section. It is thought to occur due to cerebrospinal fluid leakage and decreased intracranial pressure.

Optic nerve sheath diameter (ONSD) measured by ocular ultrasound reflects changes in intracranial pressure and may help identify patients at risk for PDPH. This prospective observational study aims to evaluate the predictive value of serial ONSD measurements for the development of PDPH in patients undergoing cesarean section under spinal anesthesia.

Non-invasive bedside ultrasound measurements of ONSD will be performed at predefined perioperative time points. Participants will be followed postoperatively to assess the occurrence of headache.

The results of this study may help improve early identification of patients at risk for PDPH and enhance postoperative management.

Inclusion Criteria:

• Women aged 18 to 45 years
• Singleton pregnancy
• Planned cesarean section (elective or emergency due to fetal indications)
• Spinal anesthesia planned for the procedure
• American Society of Anesthesiologists (ASA) physical status II-III
• Normal coagulation parameters (INR less than 1.5, platelet count greater than 100,000/mm³)
• Ability to provide written informed consent and cooperate with study procedures

Exclusion Criteria:

• Known ophthalmologic diseases affecting the optic nerve or retina (e.g., glaucoma, optic atrophy)
• Active eye infection or recent ocular surgery
• Known intracranial pathology affecting cerebrospinal fluid dynamics (e.g., intracranial mass, hydrocephalus, idiopathic intracranial hypertension)
• History of stroke or subarachnoid hemorrhage
• Hypertensive disorders of pregnancy such as preeclampsia or eclampsia
• Contraindications to spinal anesthesia (e.g., coagulopathy, anticoagulant therapy, infection at puncture site)
• Allergy to local anesthetics
• Conversion to general anesthesia due to failed or inadequate spinal block
• Presence of moderate or severe preoperative headache or active primary headache disorders such as migraine

The study includes only female participants because the research population consists of pregnant women undergoing cesarean section under spinal anesthesia.

The study population will consist of pregnant women aged 18-45 years undergoing cesarean section under spinal anesthesia at Kocaeli University Hospital. Participants who meet the eligibility criteria and provide informed consent will be enrolled.

Individual participant data will not be shared in order to protect participant privacy and confidentiality. Only aggregated study results will be reported in scientific publications.