This study aims to assess the effect of epidural anesthesia on the optic nerve sheath diameter in parturients with preeclampsia.

This prospective observational study will be performed in parturients, either with or without preeclampsia, who scheduled to undergo elective cesarean delivery under epidural anesthesia. Epidural anesthesia will be done according to the standard technique. Optic nerve sheath diameter (ONSD) will be measured before and after the epidural injection of anesthetic solutions using ultrasonography. The investigators will assess whether epidural anesthesia has effect on optic nerve sheath diameter of pregnant women, and the investigators will also compare ONSD between healthy parturients and parturients with preeclampsia. The investigators will evaluate the relationship between ONSD and disease severity of preeclampsia.

Inclusion Criteria:

• Patients scheduled to undergo planned cesarean section under epidural anesthesia if they have a singleton pregnancy, complicated by severe preeclampsia.

Severe preeclampsia was defined using the American College of Obstetricians and Gynecologist Task Force on Hypertension in Pregnancy recommendations

• Controls will be healthy pregnant women at term (>37 weeks), with a singleton pregnancy, no signs or symptoms of preeclampsia and no intrauterine fetal growth restriction, who are planned to undergo elective cesarean delivery under epidural anesthesia

Exclusion Criteria:

• Contraindication to epidural anesthesia
• Morbid cardiovascular disease
• Cerebrovascular disease
• Known fetal anomaly
• Any signs of onset of labor
• Body weight < 40 kg or body weight > 100 kg
• Height < 140cm or height > 190cm
• eye disease
• infection or trauma near the eyes
• abnormality of intracranial pressure due to Intracranial pathology

We plans to include 11 preeclamptic patients and 11 healthy pregnant women.