Warm Versus Room Temperature Saline as a Uterine Distension Medium for Pain Reduction in Women Undergoing Outpatient Hysteroscopy: Protocol for a Randomized Controlled Trial

August 15, 2026 updated by: Reem Mohamed
The goal of this randomized clinical trial is to determine whether using warmed saline at 37°C during outpatient diagnostic hysteroscopy can reduce pain compared with room-temperature saline. The study will include women aged 18 to 70 years who are undergoing outpatient diagnostic hysteroscopy. Participants will be randomly assigned to receive either warmed saline at 37°C or room-temperature saline as the fluid used to expand the uterine cavity during the procedure. Data collected will then be used to compare pain scores between the two groups during hysteroscopy and one hour after the procedure. The study will also assess whether participants require additional pain medication and whether the procedure is stopped because of severe pain. The main hypothesis is that warmed saline at 37°C will result in lower pain scores than room-temperature saline.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Outpatient diagnostic hysteroscopy is commonly performed for the evaluation of intrauterine abnormalities and other gynecological indications. Pain during hysteroscopy may be influenced by cervical manipulation, uterine distension, and uterine contractions. The temperature of the distension medium may influence patient discomfort during the procedure.

This study is a parallel-group superiority randomized controlled trial designed to compare warmed normal saline at 37°C with room-temperature normal saline as the uterine distension medium during outpatient diagnostic hysteroscopy.

Eligible participants will be women aged 18 to 70 years who are scheduled for outpatient diagnostic hysteroscopy and who are able to understand and report pain using a visual analog scale. Participants will provide written informed consent before enrollment.

A total of 60 participants will be randomized in a 1:1 ratio to one of two study groups. The intervention group will undergo hysteroscopy using normal saline warmed to 37°C. The comparison group will undergo hysteroscopy using normal saline at room temperature. The temperature of the saline will be monitored using an infrared thermometer.

Pain intensity during the hysteroscopy will be assessed using a 0-to-10 visual analog scale and will constitute the primary outcome of the study. Secondary outcomes will include pain intensity one hour after the procedure, the need for additional analgesia during or after the procedure, and the proportion of participants in whom the procedure is abandoned because of intolerable pain.

The study will be conducted in the outpatient Endoscopy Unit of Demerdash Maternity Hospital, Ain Shams University. Diagnostic hysteroscopy will be performed using a 5-mm Karl Storz hysteroscope by the same senior physician.

The study is designed to determine whether the use of warmed saline at 37°C provides a clinically meaningful reduction in pain compared with room-temperature saline during outpatient diagnostic hysteroscopy.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age 18-70 years.
  • Ability to understand and report pain using the Visual Analog Scale.
  • Willingness to undergo outpatient hysteroscopy and provide written informed consent.

Exclusion Criteria:

  • Congenital genital tract malformations: including these patients could introduce a confounding factor because pain may result from difficult anatomy rather than the temperature of the distension medium.
  • Previous hysteroscopic procedures: pain perception may be influenced by prior experience rather than the intervention itself
  • Suspected pregnancy: standard gynecologic practice considers pregnancy a contraindication to elective diagnostic hysteroscopy
  • Active pelvic infection: instrumentation of an infected genital tract may increase morbidity and facilitate ascending infection. Also, pain scores may reflect infection-related pain rather than procedural pain.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Warmed saline at 37 degrees celsius
Participants randomized to this arm will undergo outpatient diagnostic hysteroscopy using normal saline warmed to 37°C as the uterine distension medium. The planned allocation is 30 participants.
Normal saline warmed to 37°C and used as the uterine distension medium during outpatient diagnostic hysteroscopy. The temperature of the saline will be monitored using an infrared thermometer before and during the procedure.
Active Comparator: Room-Temperature Saline
Participants randomized to this arm will undergo outpatient diagnostic hysteroscopy using normal saline at room temperature as the uterine distension medium. The planned allocation is 30 participants.
Normal saline at room temperature used as the uterine distension medium during outpatient diagnostic hysteroscopy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain intensity during outpatient diagnostic hysteroscopy measured using the Visual Analog Scale (VAS)
Time Frame: During the hysteroscopy procedure
Pain intensity will be assessed using a Visual Analog Scale (VAS) ranging from 0 to 10, where 0 represents no pain and 10 represents the worst pain imaginable. The VAS score recorded immediately after the hysteroscopy will be compared between participants receiving warmed normal saline at 37°C and those receiving room-temperature normal saline.
During the hysteroscopy procedure

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain intensity one hour after outpatient diagnostic hysteroscopy measured using the Visual Analog Scale (VAS)
Time Frame: 1 hour after completion of the hysteroscopy
Pain intensity will be assessed one hour after completion of the hysteroscopy using a Visual Analog Scale (VAS) ranging from 0 to 10, where 0 represents no pain and 10 represents the worst pain imaginable. VAS pain scores will be compared between participants receiving warmed normal saline at 37°C and those receiving room-temperature normal saline.
1 hour after completion of the hysteroscopy
Need for additional analgesia after outpatient diagnostic hysteroscopy
Time Frame: 1 hour after completion of the procedure
The need for additional analgesia will be recorded as a binary outcome according to whether the participant requires analgesic medication. The proportion of participants requiring additional analgesia will be compared between the warmed saline at 37°C group and the room-temperature saline group.
1 hour after completion of the procedure
Proportion of procedures abandoned due to intolerable pain
Time Frame: During the hysteroscopy procedure
The proportion of participants in whom outpatient diagnostic hysteroscopy is abandoned because of intolerable pain will be recorded and compared between the warmed saline at 37°C group and the room-temperature saline group.
During the hysteroscopy procedure

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Collaborators

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

August 15, 2026

First Submitted That Met QC Criteria

August 15, 2026

First Posted (Actual)

August 19, 2026

Study Record Updates

Last Update Posted (Actual)

August 19, 2026

Last Update Submitted That Met QC Criteria

August 15, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • FMASU MS 555/ 2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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