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Trial registered on ANZCTR

Registration number

ACTRN12622001285741

Ethics application status

Approved

Date submitted

16/09/2022

Date registered

30/09/2022

Date last updated

30/09/2022

Date data sharing statement initially provided

30/09/2022

Type of registration

Prospectively registered

Titles & IDs

Public title

Investigating the impact of the healthy gut diet on the incidence of gestational diabetes

Scientific title

Investigating the impact of the healthy gut diet on the incidence of gestational diabetes: a multi-centre, randomised control trial in women with a prior history of gestational diabetes

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1282-6970

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Gestational diabetes mellitus

Condition category

Condition code

Reproductive Health and Childbirth

Antenatal care

Reproductive Health and Childbirth

Fetal medicine and complications of pregnancy

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Intervention group will receive dietary counselling by an Accredited Practising Dietitian with the aim to modify dietary behaviour. The target behaviour will be to eat for gut health.
The intervention consists of:
- Initial dietary counselling, up to 40 minutes long, delivered via telehealth, within 1 - 2 weeks of enrolment
- Follow-up phone call 1 (approximately 2 weeks after the initial counselling session), maximum 20 minutes
- Follow- up phone call 2 (at 28 weeks gestation), maximum 20 minutes
- 1 - 3 text messages per week (motivational, informational, links to education material) from initial counselling session completion until 36 weeks gestation. Messages will be delivered via Telstra Messaging Service which does not monitor whether messages are received by participants.
- Electronic or hard copy of dietary education, workbook, recipes, shopping lists/checklists designed specifically for this study.
- Short videos via a social media page. Following the social media page is optional and this is provide to enhance participants' understanding of the Healthy Gut Diet should they choose to seek more information. The page can be viewed at participants' discretion. We will share recipes, Healthy Gut Tips (for example, cooking tips to increase resistance starch in foods or where to find fermented foods, or what foods are high in pre-probiotic fibre) and motivational messages (for example, other benefits of building a healthy gut such as long-term health or gut microbiome transfer to baby) as a post to the page (photo and content only post with written information) or as a short 'reel' (20 - 30 second video that summarises Healthy Gut recipes or 'tips'). We will not check participants' engagement with social media. These will be designed specifically for the study.

The dietary intervention will focus on increasing the quantity and diversity of whole plant based foods, supplemented with lean animal or plant-based protein options and limiting discretionary foods and foods high in saturated fat. The healthy gut diet focuses on fibre-rich foods (wholegrains, fruit, vegetables, legumes, nuts, seeds) with adequate amounts of lean meat, chicken, fish (or alternatives) and to support a healthy pregnancy in accordance with the Australian Dietary Guidelines. Participants will also be encouraged to include naturally fermented (shop-bought) foods such as yoghurt, sauerkraut and sourdough bread (for example).

The intervention workbook will provide a staged approach to increasing fibre-rich foods over 4 weeks to reduce discomfort associated with sudden increases to fibre intake.

Adherence to the intervention will be monitored at each appointment by checking against attendance and individualised, participant-set goals. This will also be checked in the final survey (at 36 weeks) with self-reported adherence to dietary behaviour goals and frequency of using resources sent via text messages and accessing social media content.

Intervention code [1]

Lifestyle

Intervention code [2]

Behaviour

Comparator / control treatment

Usual care (choice of antenatal model of care) will be sent an electronic colour handout of general healthy eating in pregnancy advice (based on the Australian Dietary Guidelines, available here https://www.eatforhealth.gov.au/sites/default/files/content/The%20Guidelines/n55h_healthy_eating_during_pregnancy.pdf) and a short, 4-minute video explaining general healthy eating during pregnancy. The video has been designed specifically for this study and will be sent as a link via email.

Control group

Active

Outcomes

Primary outcome [1]

Diagnosis of gestational diabetes mellitus as recorded in medical records (diagnosis according to the Queensland Health Guideline available here: https://www.health.qld.gov.au/__data/assets/pdf_file/0022/950503/g-gdm.pdf)

Timepoint [1]

At any stage during the pregnancy

Secondary outcome [1]

Dietary intake (diversity and abundance of plant-foods as composite measure) assessed using baseline and 36 week short diet questionnaire (food frequency questionnaire) and 4 x 24 hour diet recalls submitted in trimester 2 and 3

Timepoint [1]

Change from baseline to 36 week gestation measured using:
- Baseline food frequency questionnaire
- 24 hour diet recall x 2 in trimester 2
- 24 hour diet recall x 2 in trimester 3
- 36 weeks food frequency questionnaire

Secondary outcome [2]

Gut Microbiota taxonomic markers (stool samples assessed using RNA shotgun sequencing by third party laboratory)

Timepoint [2]

Change from baseline to 36 weeks gestation - assessed at baseline (prior to 18 weeks gestation and at 36 weeks) via self-collected stool samples posted directly to laboratory.

Secondary outcome [3]

Gestational weight gain (within recommendations) measured according to pre-pregnancy weight (as recorded in pregnancy hand held record, usually self-reported) and weight at 36 weeks (self-reported or as per medical records), adjusted for gestation and reported continuously and categorically (inadequate, within recommendations, excessive) by pre-pregnancy body mass index and according to the Institute of Medicine's recommendations.

Timepoint [3]

Pre-pregnancy to 36 weeks gestation

Secondary outcome [4]

Pregnancy induced hypertension including preeclampsia as noted in medical records

Timepoint [4]

At any stage during pregnancy

Secondary outcome [5]

Preterm delivery (< 37 weeks) as reported in medical records

Timepoint [5]

At birth

Secondary outcome [6]

Polyhydraminos as reported in medical records

Timepoint [6]

At any stage during pregnancy

Secondary outcome [7]

Oedema as reported in medical records

Timepoint [7]

At any stage during pregnancy

Secondary outcome [8]

Large or small for gestational age as reported in medical records

Timepoint [8]

At birth

Secondary outcome [9]

Neonatal hypoglycaemia as reported in medical records

Timepoint [9]

At birth

Secondary outcome [10]

Mode of delivery as reported in medical records

Timepoint [10]

At birth

Secondary outcome [11]

Admission to special care nursery as reported in medical records

Timepoint [11]

At birth

Secondary outcome [12]

Birth Trauma as reported in medical records

Timepoint [12]

At birth

Secondary outcome [13]

Diet quality (Healthy Eating Index and Plant-based Index)

Timepoint [13]

Change from baseline to 36 weeks gestation measured using:
- Baseline food frequency questionnaire
- 24 hour diet recall x 2 in trimester 2
- 24 hour diet recall x 2 in trimester 3
- 36 weeks food frequency questionnaire

Eligibility

Key inclusion criteria

Singleton pregnancy
<18 weeks gestation at enrolment
Birthing at study hospital
Prior history of gestational diabetes mellitus

Minimum age

18 Years

Maximum age

No limit

Sex

Females

Can healthy volunteers participate?

Key exclusion criteria

Current diagnosis of gestational diabetes mellitus.
Multiples pregnancy (twins/triplets)
Women will be ineligible if they have any other form of diabetes, cystic fibrosis, inflammatory bowel disease, bariatric surgery or a bowel disorder requiring restrictive diets, a diagnosed eating disorder, complex medical co-morbidities (for example kidney or heart disease). Additional exclusion criteria will be applied to women selected for gut microbiota testing (no anti or probiotics in the 3 months prior to enrolment).

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation not concealed

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Computed generated block randomisation (block sizes 6) stored in an excel spreadsheet

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Parallel

Other design features

Data analysis will be blinded

Phase

Not Applicable

Type of endpoint/s

Safety/efficacy

Statistical methods / analysis

Comparisons between control and intervention groups for all outcome measures will be made using regression models that include the independent variable of group (treatment / control) and other potential confounders. Demographic outcomes will be described (frequencies and percents or mean and standard deviation) and used in regression analysis to adjust for confounding variables.
The primary outcome will be difference in gestational diabetes mellitus (GDM) diagnosis between groups.
The anticipated dietary intake difference between groups will be used to examine the effects on the gut microbiota. Microba will provide the full analysis of measures of gut microbiota (i.e. alpha and beta diversity, functional profiles). Analysis will include multiple regression models with an outcome of the change in microbiota (baseline to 36 weeks) and how this is associated with the change in diet. These models will adjust for baseline microbiota and other potential confounders, such as age, Gestational weight gain (GWG) and GDM treatment. The confounders for each model will be determined using causal diagrams, which transparently illustrate the model and assumptions.
Results will be reported using an intention-to-treat approach, so all women in the intervention arm will be included in the primary analysis. In a sensitivity analysis, a per protocol approach will be used - data from women who did not complete the three dietary counselling sessions will be excluded from this analysis. The intention-to-treat analysis gives the most realistic picture of the intervention in practice, whereas the per protocol analysis indicates the possible benefits if treatment adherence can be increased.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

2/01/2023

Actual

Date of last participant enrolment

Anticipated

30/04/2024

Actual

Date of last data collection

Anticipated

31/10/2024

Actual

Sample size

Target

140

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

QLD

Recruitment hospital [1]

Caboolture Hospital - Caboolture

Recruitment hospital [2]

Redcliffe Hospital - Redcliffe

Recruitment postcode(s) [1]

4510 - Caboolture

Recruitment postcode(s) [2]

4020 - Redcliffe

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

Queensland Department of Health - Health Innovation, Investment and Research Office

Address [1]

33 Charlotte Street, Brisbane QLD 4000

Country [1]

Australia

Funding source category [2]

University

Name [2]

The University of Queensland

Address [2]

St Lucia
Queensland 4067

Country [2]

Australia

Primary sponsor type

University

Name

The University of Queensland

Address

St Lucia
Brisbane, Queensland 4067

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Metro North Human Research Ethics Committee (RBWH Committee A)

Ethics committee address [1]

Level 7, Block 7
Royal Brisbane and Women’s Hospital
Butterfield Street, Herston QLD 4029

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

21/12/2021

Approval date [1]

03/03/2022

Ethics approval number [1]

HREC/2021/QRBW/82350

Summary

Brief summary

We will recruit pregnant women with a prior history of gestational diabetes mellitus (GDM) as part of a randomised control trial (RCT) to undertake the healthy gut dietary intervention (or control). We hypothesise that women who are provided dietitian counselling and education about a Healthy Gut Diet will improve their gut health (measured as the gut microbiome) and be less likely to develop GDM.
The primary outcome will the proportion of women developing GDM. Other outcomes include changes to gut microbiota, diet quality, gestational weight gain, and maternal and infant outcomes. The study sites are Redcliffe and Caboolture Hospitals.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Nina Meloncelli

Address

Metro North Allied Health
Office of the Chief Allied Health Practitioner
Level 13, Block 7
Royal Brisbane and Women's Hospital
Cnr Butterfield St and Bowen Bridge Rd
Herston QLD 4032

Country

Australia

Phone

+61 407695625

Fax

[email protected]

Contact person for public queries

Name

Nina Meloncelli

Address

Metro North Allied Health
Office of the Chief Allied Health Practitioner
Level 13, Block 7
Royal Brisbane and Women's Hospital
Cnr Butterfield St and Bowen Bridge Rd
Herston QLD 4032

Country

Australia

Phone

+61 407695625

Fax

[email protected]

Contact person for scientific queries

Name

Nina Meloncelli

Address

Metro North Allied Health
Office of the Chief Allied Health Practitioner
Level 13, Block 7
Royal Brisbane and Women's Hospital
Cnr Butterfield St and Bowen Bridge Rd
Herston QLD 4032

Country

Australia

Phone

+61 407695625

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

Non-identified, individual participant data of published results only.

When will data be available (start and end dates)?

Per university specifications - Not until 2025, available for 15 years after publication

Available to whom?

To university approved applicants

Available for what types of analyses?

Upon negotiation

How or where can data be obtained?

Application to the University of Queensland by first emailing the Principal Investigator ([email protected])

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Preventing Gestational Diabetes with a Healthy Gut Diet: Protocol for a Pilot, Feasibility Randomized Controlled Trial.	2023	https://dx.doi.org/10.3390/nu15214653

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically