Early Labor Pre-Marking for Epidural Analgesia: Ultrasound vs Manual Palpation

Summary

The goal of this clinical trial is to learn if finding and marking the best spot on the back early in labor helps doctors perform epidural pain relief more successfully in pregnant women. Usually, epidural pain relief is requested when labor pain is already severe, which makes it hard for women to hold still. This makes it difficult to find the right needle spot, leading to more needle attempts

The main questions this study aims to answer are:

* Does using ultrasound to mark the back early in labor (before severe pain starts) help the doctor place the needle correctly on first try without adjusting it?
* Does this early marking method lower the number of needle attempts and the time it takes to finish the procedure? Researchers will compare marking the back using an ultrasound machine to the standard method of feeling the spine with hands. Both methods will be done early in the waiting room to avoid the challenges caused by severe pain. Importantly, neither the pregnant women nor the doctors performing the epidural will know which marking method was used. This design prevents personal beliefs or expectations from affecting the procedure, making the study results objective and trustworthy.

Participants will, if consented and participated in the study:

* Have their lower back examined and marked by a doctor early in labor using either an ultrasound machine or the doctor's hands.
* Receive an epidural pain relief in the delivery room when they request it. This will be done by a different doctor who does not know how the back was marked.
* Answer short questions about their pain level and how happy they are with the procedure.

Conditions

• Labor Pain
• Epidural Analgesia for Labour and Delivery
• Neuraxial Ultrasound

Interventions

PROCEDURE

Preprocedural Spinal Ultrasound

A curvilinear probe is applied to the lower back in a transverse orientation. The vertebral midline is marked after identifying a symmetrical image in the transverse spinous process view. The probe is then oriented to obtain a paramedian sagittal laminar view. After locating the sacrum and lumbosacral junction, the probe is moved cephalad to identify and mark the L3 and L4 laminae. The probe is rotated back to a transverse view to systematically assess the lumbar interlaminar spaces, using the posterior complex (ligamentum flavum, epidural space, and posterior dura) and the anterior complex (anterior dura, posterior longitudinal ligament, and posterior vertebral body) as key landmarks. Markings are done with pen at four midpoints of the probe's edges in the L3-L4 space with the largest acoustic window. The intersection of horizontal and vertical lines drawn from these marks designates the needle insertion point.

PROCEDURE

Conventional Landmark Palpation

The anesthesiologist manually palpates anatomical landmarks to identify L3-L4 interspace and marks the midline insertion site. An ultrasound probe is then placed over this marked site only to measure skin-to-epidural depth for data collection purposes. These measurements are recorded but are not used to adjust or alter the marked insertion point.

Sponsors & Collaborators

• University Medical Center Ho Chi Minh City (UMC)

  lead OTHER

Principal Investigators

• An Vu Nguyen, MD, MSc · University Medical Center Ho Chi Minh City

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-06-01

Primary Completion

2026-08-30

Completion

2026-08-30

Countries

• Vietnam

Study Locations