Spinal anesthesia-induced hypotension remains a common and significant complication during cesarean sections, posing risks for both mother and fetus. Vitamin D deficiency, frequently observed in pregnant women, is associated with altered vascular function and potential hemodynamic instability. This prospective observational study aims to investigate whether vitamin D deficiency is associated with an increased incidence and severity of spinal anesthesia-induced hypotension in pregnant women undergoing elective cesarean delivery. Vitamin D levels will be measured preoperatively, and intraoperative hemodynamic parameters will be closely monitored. The findings could contribute to improved management strategies for pregnant patients at risk of severe hypotension.

Detailed Description Spinal anesthesia is the most commonly used technique for cesarean section and is associated with a high incidence of maternal hypotension, which can adversely affect both maternal well-being and neonatal outcomes. Despite standard preventive strategies such as fluid preloading and vasopressor use, significant hypotension still occurs in a considerable proportion of patients.

Vitamin D deficiency is a prevalent condition among pregnant women and has been implicated in the modulation of cardiovascular and autonomic functions. Low serum levels of 25-hydroxyvitamin D may impair vascular smooth muscle contractility, endothelial function, and baroreflex sensitivity, potentially contributing to exaggerated hypotensive responses under spinal anesthesia.

This prospective observational study aims to evaluate the relationship between maternal vitamin D status and the incidence and severity of spinal anesthesia-induced hypotension during elective cesarean delivery. Eligible pregnant women scheduled for elective cesarean section under spinal anesthesia will have their serum 25-hydroxyvitamin D levels measured preoperatively. Intraoperative hemodynamic parameters will be continuously monitored, and episodes of hypotension will be recorded and analyzed in relation to vitamin D status.

The primary outcome of the study is the incidence of spinal hypotension, defined as a ≥20% decrease in systolic blood pressure from baseline or an absolute value below 90 mmHg. Secondary outcomes include total vasopressor dose, fluid requirement.

Findings from this study may identify vitamin D deficiency as a novel risk factor for spinal anesthesia-induced hypotension and inform new preventive strategies for hemodynamic management in cesarean deliveries

Inclusion Criteria:

• Pregnant women aged 18 years or older
• Scheduled for elective cesarean delivery under spinal anesthesia
• Able and willing to provide written informed consent

Exclusion Criteria:

• Emergency cesarean sections
• History of significant cardiovascular disease (e.g., arrhythmia, heart failure)
• Known neurological disorders affecting autonomic function
• Current vitamin D supplementation within the past 30 days
• Inability to undergo blood sampling or provide valid hemodynamic data
• Contraindication to spinal anesthesia

Pregnant women aged 18 years and older who are scheduled for elective cesarean section under spinal anesthesia at a tertiary care university hospital. All participants will be clinically stable and provide informed consent prior to enrollment. The study population will be stratified based on serum vitamin D levels into deficient and sufficient groups for analysis of hypotension outcomes.

The study involves sensitive clinical data from pregnant women. Individual participant data will not be shared publicly due to privacy concerns.