Intra-abdominal Pressure, Abdominal Circumference, and Spinal Block Level in Cesarean Section

The Effect of Intra-abdominal Pressure and Abdominal Circumference on Sensory Block Level After Spinal Anesthesia in Pregnant Women Undergoing Cesarean Section

Spinal anesthesia is commonly used for cesarean section and provides effective anesthesia with rapid onset. However, the spread of spinal anesthesia may vary among pregnant women due to physiological and anatomical changes during pregnancy. Increased intra-abdominal pressure and abdominal circumference may influence cerebrospinal fluid dynamics and affect the level of sensory block achieved after spinal anesthesia.

This prospective observational study aims to evaluate the relationship between intra-abdominal pressure, abdominal circumference, and the maximum sensory block level following spinal anesthesia in pregnant women undergoing cesarean section. Intra-abdominal pressure and abdominal circumference will be measured before surgery, and sensory block levels and hemodynamic parameters will be assessed after spinal anesthesia. The findings of this study may help to better understand factors affecting spinal block spread in pregnant patients.

Study Overview

• Status: Completed
• Conditions: Pregnancy; Cesarean Section; Elective Cesarean Section

• Study Type: Observational
• Enrollment (Actual): 107

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Kütahya
    • Kütahya, Kütahya, Turkey (Türkiye)
      • Kütahya Şehir Hastanesi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This study includes pregnant women aged 18-40 years who were scheduled for elective cesarean section under spinal anesthesia at the Department of Obstetrics and Gynecology, Kütahya City Hospital. Eligible participants belonged to ASA physical status II-III and provided informed consent. The study population represents a clinically stable obstetric cohort undergoing elective cesarean delivery, without conditions known to significantly alter intra-abdominal pressure or spinal anesthesia characteristics.

Description

Inclusion Criteria:

• Pregnant women aged 18-40 years
• Scheduled for elective cesarean section at Kütahya City Hospital
• Planned spinal anesthesia
• ASA physical status II-III
• Provided written informed consent

Exclusion Criteria:

• Refusal to participate in the study
• Emergency cesarean section
• Preeclampsia or other hypertensive disorders of pregnancy
• Onset of labor or premature rupture of membranes
• Clinical conditions affecting intra-abdominal pressure, including peripheral edema or ascites
• Height <140 cm or >180 cm
• Body mass index < 40 kg/m²
• Spinal deformity or history of spinal surgery
• Contraindications to neuraxial anesthesia
• Known allergy to bupivacaine
• Requirement for additional surgical procedures other than cesarean section
• Conditions contraindicating or interfering with intra-abdominal pressure measurement, including active or previous postdural puncture headache, neurogenic bladder, hematuria, or incidental abdominal mass

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum sensory block level after spinal anesthesia	The maximum dermatomal level of sensory block assessed by loss of cold sensation after spinal anesthesia.	Within the first 30 minutes after spinal anesthesia

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intra-abdominal pressure	Intra-abdominal pressure measured in the preoperative period before spinal anesthesia and in the postoperative period following cesarean section using an intravesical measurement technique.	Baseline (preoperative, before spinal anesthesia) and early postoperative period (within 30 minutes after cesarean section)
Abdominal circumference	Abdominal circumference measured at the level of the umbilicus before spinal anesthesia and in the postoperative period following cesarean section.	Baseline (preoperative, before spinal anesthesia) and early postoperative period (within 30 minutes after cesarean section)
Incidence of hypotension after spinal anesthesia	Hypotension defined as mean arterial pressure <65 mmHg measured during the first 30 minutes after spinal anesthesia.	Within the first 30 minutes after spinal anesthesia
Vasopressor requirement	Requirement and total dose of vasopressor agents administered after spinal anesthesia.	Perioperative period

Collaborators and Investigators

• Sponsor: Kutahya Health Sciences University

Study record dates

Study Major Dates

• Study Start (Actual): February 7, 2026
• Primary Completion (Actual): April 1, 2026
• Study Completion (Actual): April 30, 2026

Study Registration Dates

• First Submitted: January 23, 2026
• First Submitted That Met QC Criteria: February 5, 2026
• First Posted (Actual): February 12, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: intra-abdominal pressure; spinal anesthesia; sensory block level; obstetric anesthesia; spinal block; abdominal circumference
• Other Study ID Numbers: 2025/08-28