A Study Using Breath Tests to Identify Patients at Risk for Gestational Diabetes

January 8, 2026 updated by: Maya Oberman, Kaplan Medical Center

A Pilot Study Evaluating the Use of a Novel Noninvasive Breath Test to Identify Patients at Risk for Developing Gestational Diabetes

The aim of our study is to evaluate the feasibility, and diagnostic value of oral 13C labelled glucose breath test compared to the GCT and OGTT tests.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This prospective observational pilot study will include pregnant patients with a singleton fetus up to 33 weeks gestation.

Patients meeting the inclusion criteria who are willing to participate will be asked to drink 50 or 100 grams of glucose in 200 ml water (disposable plastic cup). The test will start at approximately 08:00 with no change in normal diet is needed prior to the GCT, or after an 8-14 hour overnight fast for the OGTT.

The test will be performed at the Maternal Fetal Medicine outpatient clinics, the Maternal Fetal Medicine unit for inpatients or at the patient's residence.

Samples collection

Glucose samples:

  1. Venous blood samples to measure serum glucose levels will be drawn at a timing according to the performed test: for GCT at one hour after the ingestion of glucose (standard 50 grams GCT) and for OGTT at to, t1, t2 and t3 (standard 100 grams OGTT).
  2. Finger prick glucometer (DEX) readings will be done at one and two hours after the ingestion of glucose for participants completing GCT.

Each participant will receive a kit containing 30 12ml exetainers (Labco, UK), a compatible strew and a stamped envelope (addressed to OBGYN department, Kaplan Medical Center, Rehovot). The exetainers will be numbered sequentially and marked by the participant code (initials and participant number). After a short explanation on how to use the kit participants will be asked to sample their breath every 15 minutes starting 30 minutes before the ingestion of glucose and ending six hours after the ingestion. Patients who are taking the test at the Maternal Fetal Medicine clinic will be asked to remain at the clinic for the duration of six hours, until completing all of the samples. Patients who are taking the test while admitted to the Maternal Fetal Medicine ward and are due for discharge will not be delayed as discharge is usually until 14:00. During the six hours of participation patients will be ask to avoid food or drink. Afterwards, participants will keep the envelope in their home until a pickup is coordinated by a member of the research team.

Samples can be kept up to three months before being processed. The coded samples will next be sent to Amir Shafat's lab at Ireland for processing. Samples will be analyzed on a continuous-flow Isotope Ratio Mass Spectrometer (ABCA, Serco, UK) for breath CO2 enrichment against Vienna-Pee Dee Belemnite, a known international standard for 13C. Enrichment will be expressed in atom fraction and δV-PDB. Pilot data in Amir's lab demonstrated that this procedure gives excellent resolution of breath enrichment (to within 1 part per million) and includes peak excretion of 13CO2 in all volunteers. Percent dose recovered and other parameters indicating the rate of glucose oxidation will be calculated from the enrichment curve. Amir's laboratory has extensive experience in stable isotope and breath testing.

A few days (and no longer than one week) after the test participants will receive their GCT or OGTT result by phone and fax/email. Participants will be asked to present the test result to their physician in the next prenatal visit. For participants with a pathological GCT score, >139 mg/dL, a letter will be sent to the attending physician requesting to perform the 100 grams OGTT either as part of the study or at the health care provider clinic. Participants with one or more elevated glucose values in the OGTT, will be asked to contact their physician as soon as possible for further guidance. Two weeks after the test, a follow-up phone call will be done to all participants with a pathological result in order to ensure that the OGTT had been completed and to record the OGTT result in case of a pathological GCT, or to ensure the appropriate surveillance has begun in case of a pathological OGTT.

Demographic data including: a) maternal age; b) maternal height: c) pre-pregnancy and current weight; d) obstetrical history e) background medical illnesses and medications.

Sample size estimation In this pilot study the investigators aim to recruit 50 participants in each group (GCT and OGTT) out of which it is expected that 8-11 will have pathological result (16-21% pathological GCT).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Contacts and Locations

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

Study Locations

  • Israel
      • Rehovot, Israel
        • Kaplan Medical Center

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

This prospective observational pilot study will include pregnant patients with a singleton fetus up to 33 weeks gestation.

Description

Inclusion Criteria:

  • Pregnant women
  • ages 18 to 45 years old
  • A singleton pregnancy
  • Confirmed gestational age by a documented first-trimester ultrasound.

Exclusion Criteria:

  • Patients below the age of 18 or above 45 years-old
  • Patients diagnosed with gestational or pre-gestational diabetes
  • Patients with multiple pregnancies or fetuses with congenital and/or chromosomal anomalies
  • Patients after a multifetal pregnancy reduction (spontaneous or iatrogenic)
  • Patients not having a sonographic dating during the first trimester of pregnancy
  • Patients with conditions or medications that affect glucose metabolism
  • Patients who will refuse to consent, or are not fit or able to read, understand, or sign an informed consent.

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

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
The aim of our study is to evaluate the feasibility of oral 13C labelled glucose breath test compared to the GCT and OGTT tests.
Time Frame: At the time of the glucose tolerance test (GCT/ OGTT)
We will assess feasibility via recruitment and test completion.
At the time of the glucose tolerance test (GCT/ OGTT)
To evaluate the diagnostic value of oral 13C labelled glucose breath test compared to the GCT and OGTT tests.
Time Frame: At the time of the glucose tolerance test (GCT/ OGTT)
We will assess agreement between exogenous glucose oxidation (breath test) and blood glucose (OGTT).
At the time of the glucose tolerance test (GCT/ OGTT)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Kaplan Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Galway

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 18, 2020

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 20, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 20, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 21, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 8, 2026

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 16, 2026

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 0116-19-KMC

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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