Comparison of the Efficacy of Intravenous Fluid Administration Between Bolus and Continuous Infusion in Pregnant Women With Fetal Heart Rate Tracing Category II: A Randomized Controlled Trial (Bolus fluid)

The goal of this clinical trial is to compare the efficacy of two methods of intravenous (IV) fluid administration-bolus infusion versus continuous infusion-for intrauterine resuscitation in pregnant women who present with Category II fetal heart rate (FHR) tracings during labor. The main research question is:

Does intrauterine resuscitation using an adjusted IV hydration bolus of normal saline more effectively convert the FHR tracing from Category II to Category I within 30 minutes compared to adjusted IV hydration using a continuous infusion of 1000 mL normal saline at 150 mL/hour? Objectives

Primary Objective:

- To compare the rate of improvement of electronic fetal monitoring (EFM) category from Category II to Category I within 30 minutes between two hydration methods: Normal saline bolus loading (adjusted dose) Normal saline continuous infusion (1000 mL at 150 mL/hr)

Secondary Objectives:

• To identify the characteristics of IV fluid administration used during intrauterine resuscitation.
• To determine whether fluid bolus improves fetal heart rate patterns more rapidly or effectively than continuous infusion.

Methods

Study Design: Randomized controlled trial with block randomization (block of four).

Participants: Pregnant women in labor who present with Category II FHR tracing on admission.

Intervention:

Group A: Adjusted IV hydration with normal saline bolus loading. Group B: Adjusted IV hydration with normal saline continuous infusion (1000 mL at 150 mL/hr).

Monitoring: Electronic fetal monitoring (EFM) will be continuously observed to detect any change in FHR category after intervention.

Primary Outcome: Conversion of FHR from Category II to Category I within 30 minutes.

Study Overview

• Status: Recruiting
• Conditions: Fetal Non Reassuring
• Intervention / Treatment: Drug: Giving 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour

Detailed Description

This is a randomized controlled trial study to compare the efficacy of two methods of intravenous (IV) fluid administration-bolus infusion versus continuous infusion-for intrauterine resuscitation in pregnant women who present with Category II fetal heart rate (FHR) tracings during labor

There are 2 interventions :

Intervention 1 (Bolus Group):

Participants receive 500 mL of normal saline (NSS) intravenously as a bolus over 20 minutes, followed by 1,000 mL of NSS infused continuously at 150 mL/hour.

Intervention 2 (Continuous Infusion Group):

Participants receive 1,000 mL of normal saline infused continuously at 150 mL/hour without a preceding bolus.

Short-term Outcome Collection

Primary short-term outcome:

Conversion of FHR Category II to Category I within 30 minutes after starting the assigned IV hydration regimen, assessed by continuous electronic fetal monitoring (EFM).

Secondary short-term outcomes:

Measured at baseline, 10 minutes, and 30 minutes after intervention:

Maternal hemodynamic parameters: Blood pressure, heart rate, respiratory rate, SpO₂ IVC collapsibility index (IVC-CI) assessed by ultrasound (M-mode) Umbilical artery Doppler indices: Resistance Index (RI), Pulsatility Index (PI), S/D ratio FHR variability and deceleration pattern All outcomes are recorded in the Case Record Form (CRF) by blinded assessors. All participants are women in labor with Category II fetal heart rate (FHR) tracing, randomized by block randomization (block size = 4).

During the intervention, standard intrauterine resuscitation measures (maternal left lateral position, discontinuation of oxytocin, oxygen 15 L/min by mask if indicated) are maintained uniformly.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tawanrat Anannaweenusorn; Phone Number: +66868162510; Email: Anantawanrat@gmail.com
• Study Contact Backup: Name: Phanubhan Meepon; Phone Number: +66643644653; Email: t_op038@hotmail.com

Study Locations

• Thailand
  • Changwat Chon Buri
    • Si Racha, Changwat Chon Buri, Thailand, 20110
      • Recruiting
      • Queen Savang Vadhana Memorial Hospital, Chon Buri, Chon Buri 20110 Recruiting
      • Contact: Surachat Jaroenwareekul, M.D.; Phone Number: +6638322157; Email: Surachatjwk@gmail.com
      • Contact: Chuenrutai Yeekian, Ph.D.; Phone Number: 23468 +6638322157; Email: JayeekianBB@gmail.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Singleton
2. Thai nationality
3. Gestational Age more than equal 37 Weeks
4. Maternal Age 20-35 Years
5. Cephalic Presentation
6. Electronic Fetal Monitoring (EFM) Category II

Exclusion Criteria:

1. Maternal underlying diseases : Cardiac disease, Pulmonary disease), Overt DM, Thyroid disease,. etc
2. High risk pregnancy :Pre-eclampsia/Eclampsia), GDM
3. Fetal abnormalities
4. Maternal receiving medications for example : Magnesium sulfate, Pethidine, Opioids
5. Oligohydramnios

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group A (Bolus group): Receives 500 mL of normal saline intravenously as a bolus; Receives 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour	Drug: Giving 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour; Giving 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour which the another one will be giving 1,000 mL of normal saline at 150 mL/hour without a preceding bolus.
Experimental: Group B (Continuous infusion group): Receives 1,000 mL of normal saline at 150 mL/hour; Group B (Continuous infusion group): Receives 1,000 mL of normal saline at 150 mL/hour without a preceding bolus	Drug: Giving 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour; Giving 500 mL of normal saline intravenously as a bolus over 20 minutes, followed by 1,000 mL normal saline at 150 mL/hour which the another one will be giving 1,000 mL of normal saline at 150 mL/hour without a preceding bolus.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To compare the rate of improvement of electronic fetal monitoring (EFM) category from Category II to Category I within 30 minutes	To compare the rate of improvement of electronic fetal monitoring (EFM) category from Category II to Category I within 30 minutes between two hydration methods: Normal saline bolus loading (adjusted dose); Normal saline continuous infusion (1000 mL at 150 mL/hr)	30 minutes

Collaborators and Investigators

• Sponsor: Queen Savang Vadhana Memorial Hospital, Thailand

Study record dates

Study Major Dates

• Study Start (Estimated): December 5, 2025
• Primary Completion (Estimated): December 30, 2025
• Study Completion (Estimated): March 30, 2026

Study Registration Dates

• First Submitted: November 20, 2025
• First Submitted That Met QC Criteria: November 20, 2025
• First Posted (Estimated): December 3, 2025

Study Record Updates

• Last Update Posted (Estimated): December 3, 2025
• Last Update Submitted That Met QC Criteria: November 20, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Bolus fluid administration, Non-reassuring fetal status, Fetal distress, Intrauterine resuscitation
• Additional Relevant MeSH Terms: Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Fetal Distress
• Other Study ID Numbers: 013/2568

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Data was saved in form of Microsoft excel spreadsheet and SPSS file

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No