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Trial registered on ANZCTR


Registration number
ACTRN12610000681055
Ethics application status
Approved
Date submitted
13/08/2010
Date registered
18/08/2010
Date last updated
14/08/2015
Type of registration
Prospectively registered

Titles & IDs
Public title
GI Baby 3: A dietary intervention during pregnancy to reduce child obesity – a randomized, controlled trial
Scientific title
A randomized, two-arm parallel dietary intervention study to compare the effects of consuming a low glycemic diet or wholegrain high fibre diet on infant birth weight and body composition, complications related to Gestational Diabetes Mellitus (GDM) and progression to GDM diagnosis in women at high-risk of GDM.
Secondary ID [1] 252066 0
Nil
Universal Trial Number (UTN)
Trial acronym
GI Baby 3
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gestational Diabetes Mellitus 257607 0
Condition category
Condition code
Diet and Nutrition 257782 257782 0 0
Other diet and nutrition disorders
Metabolic and Endocrine 258149 258149 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Low Glycemic Index (GI) diet, consisting of protein (15 – 25%), fat (30 – 35%) and carbohydrate (45 – 50%) content and a low dietary GI less than 50. Carbohydrate choices for the low GI diet will include pasta, low GI rice, low GI breakfast cereals and breads. The intervention duration is from 20 weeks gestation until birth. The intervention involves five consultations with an accredited practising dietitian (APD) at 20, 24, 28, 32 and 36 weeks of gestation. At weeks 20 and 36, the approximate duration of each dietary education session is 60 minutes. At weeks 24, 28 and 32, the approximate duration of each dietary education session is 30 minutes. Handouts and recipes will be provided, and the participants will have access to the research dietitian via phone throughout their participation period. Participants will receive a food basket at each of the five education sessions with the dietitian (at week 20, 24, 28, 32 and 36 weeks of gestation) containing foods that are low GI to improve their compliance and understanding of the advised food choices.
Intervention code [1] 257008 0
Prevention
Comparator / control treatment
Wholegrain high fibre diet, consisting of protein (15 – 25%), fat (30 – 35%) and carbohydrate (45 – 50%) content and a GI of approximately 60 (average GI of a normal healthy diet). Carbohydrate choices for the wholegrain high fibre diet will include potatoes, brown rice, wholemeal breads and wholegrain breakfast cereals. The intervention duration is from 20 weeks gestation until birth. The intervention involves five consultations with an accredited practising dietitian (APD) at 20, 24, 28, 32 and 36 weeks of gestation. At weeks 20 and 36, the approximate duration of each dietary education session is 60 minutes. At weeks 24, 28 and 32, the approximate duration of each dietary education session is 30 minutes. Handouts and recipes will be provided, and the participants will have access to the research dietitian via phone throughout their participation period. Participants will receive a food basket at each of the five education sessions with the dietitian (at week 20, 24, 28, 32 and 36 weeks of gestation) containing foods that are wholegrain high fibre to improve their compliance and understanding of the advised food choices.
Control group
Active

Outcomes
Primary outcome [1] 258984 0
Birth weight Z-score.

The birth weight z-score is calculated as:
Birth weight z-score = (XGA - MGA)/SDGA
Where XGA is the measured birth weight at a known gestational age (GA), MGA is the mean value according to the reference used at this GA and SDGA is the standard deviation of the mean value at this GA according to the reference.
Timepoint [1] 258984 0
Birth weight of the infants will be obtained from the NSW Midwife Data Sheet, which is in the medical record of their mothers.
Secondary outcome [1] 265174 0
Detection of GDM

During the study, the criteria used for diagnosis of GDM will be the current Australian criteria for GDM diagnosis.
Timepoint [1] 265174 0
At any of the five individual nutrition counselling sessions (at gestation week 20, 24, 28, 32, and 36).
Secondary outcome [2] 265175 0
Need for insulin use

Commencement of insulin therapy will be noted and presented as prevalence in treatment group. The units of insulin required will also be noted and the mean +/- Standard Error of the Mean (SEM) of the two treatment groups will also be compared.
Timepoint [2] 265175 0
During the study, the Blood Glucose Level (BGL) of the participants are closely monitored via Home Blood Glucose Monitoring (HBGM). Participants will be asked to conduct HBGM at fasting (upon waking in the morning prior to breakfast) and one hour after breakfast, lunch and dinner, from 20 weeks gestation until birth. Once the Diabetes Educator noticed 3 or more readings of the HBGM are outside the reference range, they will commence insulin therapy for optimal BGL control.
Secondary outcome [3] 265176 0
Ponderal index

Ponderal index is calculated as the weight of infant divided by the cube of his/her length.
Timepoint [3] 265176 0
The weight and length of the infants at birth will be collected from the NSW Midwife Data Sheet.
Secondary outcome [4] 265177 0
Infant body composition The PEA POD is an Air Displacement Plethysmograph which uses whole-body densitometry to determine body composition (percent fat and fat-free mass) in infants. The 7-minute test consists of measuring the subject's mass (weight) using a very precise electronic scale, and volume, which is determined while the infant lies inside the PEA POD chamber. From these two measurements, the infant's body composition is calculated. The PEA POD consists of two chambers. The Test Chamber is accessed through the Test Chamber Door and is where the infant is placed while in the Test Chamber Tray for the volume measurement. The acrylic Window allows the infant to be viewed at all times while inside the Test Chamber. The second, or Reference Chamber, is located inside the PEA POD. During the brief data collection period of the volume measurement, the chamber door is secured by an electromagnet. A Diaphragm, mounted internally between the two chambers, oscillates during testing and causes small changes in volume inside the chamber. The pressure response to these small volume changes is measured by first determining the interior volume of the empty PEA POD chamber, then measuring it again with the infant inside. By subtraction, the infant's body volume is obtained.
Timepoint [4] 265177 0
Infant body composition of the infants will be measured at birth and obtained from the NSW Midwife Data Sheet, which is in the medical record of their mothers.
Secondary outcome [5] 265178 0
Blood parameters Fasting BGL, fasting insulin, glycosylated haemoglobin (HbA1c), Liver function test (LFT), uric acid, thyroid stimulating hormone (TSH), fructosamine, triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol, adiponectin, C-reactive protein (CRP), high-sensitivity C-reactive protein (hsCRP) will be measured and results will be presented as mean +/- SEM of the two treatment groups and compared.
Timepoint [5] 265178 0
Blood samples will be collected at gestation week 20 and 36 (baseline and last visits).
Secondary outcome [6] 265179 0
Maternal Weight Gain. Body weight is measured in kilograms and recorded to one decimal place. Subjects will be weighed on calibrated scales wearing only light indoor clothing with shoes off. Heavy items such as keys, jewelleries, etc. are to be removed before weighing. Maternal weight gain will be calculated as the difference between the weight at first and last visit.
Timepoint [6] 265179 0
Subjects will be weighed on every antenatal visit (at gestation weeks 20, 24, 28, 32 and 36) and their weights will be recorded.
Secondary outcome [7] 265180 0
Pregnancy complications Any pregnancy complications occurred, e.g. need for caesarean session, shoulder dystocia, etc. will be noted. Data will be presented as prevalence in treatment group
Timepoint [7] 265180 0
Medical records of the participants will be obtained at the end of their participation.
Secondary outcome [8] 265181 0
Dietary assessment The subjects were asked to estimate quantities but NOT to weigh foods. The 3-day food records (one from the beginning of the study) will be entered into Food Works Professional (v 2007, Xyris Software, Brisbane) for macro- and micro-nutrient analysis. Dietary glycemic index (GI) and glycemic load (GL) will also be calculated. The 24-hour recalls will also be entered to Food Works for dietary GI and GL analysis. Where the glycemic index value of a food item in the food record is not available, a systematic method based on the work of Flood et al would be used to assign a closest possible GI value. The dietary GI and GL of the two 3-day food records will be compared to determine change in dietary pattern/habits.
Timepoint [8] 265181 0
Compliance to the diet will be assessed throughout the study using 24-hour recalls during the sessions at gestation week 24, 28 and 32. In addition, subjects will be asked to complete a detailed 3-day food record prior to their baseline and last visit at gestation week 20 and 36.
Secondary outcome [9] 265398 0
Genotyping The FTO gene is large encompassing >410kb of genomic region on chromosome 16. The most significantly associated single nucleotide polymorphism (SNP) with obesity, rs993960916 will be analysed for this study group. Subjects will be genotyped for the FTO gene through the collection of one blood sample for each mother and infant and following standard methodology of gene analysis.
Timepoint [9] 265398 0
Subjects will be genotyped for the FTO gene through the collection of two blood samples for each mother at baseline (gestation week 20) and gestation week 36, and the infant's cord blood is taken at birth of the infant.
Secondary outcome [10] 265399 0
Placental/Umbilical Cord Blood (UCB) Collection Immediately after the birth of the baby (either by vaginal delivery or by caesarian section) the umbilical cord is clamped and cut in the normal manner separating the baby from the placenta and mother. The portion of the umbilical cord still attached to the placenta is then cleaned. A needle is then inserted into the umbilical vein and the placental blood is drawn, by gravity flow, into a sterile blood collection bag containing anti-coagulant to prevent the blood from clotting. UCB samples will be collected at the birth of the infant. Inflammatory markers such as Interleukin 6 (IL-6), leptin and C-Reactive Protein (CRP) will be measured.
Timepoint [10] 265399 0
The Placental/Umbilical Cord Blood (UCB) is the blood that remains in the placenta and umbilical cord following birth, and this will be collected at the delivery of the baby.

Eligibility
Key inclusion criteria
Pregnant: between 14-20 weeks of gestation And one or more of the following GDM risk factors: 1. Age: > 30 years 2. Family history of type 2 diabetes- first-degree relatives with type 2 diabetes 3. Overweight or obese: Pre-pregnancy Body Mass Index (BMI) > 30 (Kg/m2) 4. Past history of GDM or glucose intolerance 5. History of ‘large for gestational age’ babies: Previous baby > 4kg 6. Belonging to a high-risk ethnic group: Aboriginal or Torres Strait Islander, Polynesian, Middle Eastern, Indian and Asian. 7. Ability to read and understand participant information and consent form 8. Ability to comply with the scheduled visits and dietary advice
Minimum age
No limit
Maximum age
No limit
Sex
Females
Can healthy volunteers participate?
Yes
Key exclusion criteria
1. Pregnancy achieved by assisted reproduction 2. Smoking 3. Special dietary requirements (e.g. gluten intolerance, celiac disease) 4. Pre-existing type 1 or type 2 diabetes 5. GDM diagnosis <20weeks of gestation: Oral Glucose Tolerance Test (OGTT) showing high fasting greater than or equal to 5.8mmol/L & 2 hr Blood Glucose Level (BGL) reading greater than or equal to 11.1 mmol/L

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)
Participants will be recruited from the pool of pregnant women with GDM risk factors who attend the Royal Prince Alfred Hospital (RPAH) Antenatal Clinic and Babies Parent Education Centre. The study research dietitian will ask women who are in interested in participating in a dietary study to either stay behind or leave contact details, and will explain the requirements of the study and answer questions about it.

Participants will be randomized by computer generated random numbers to 2 different diets, namely the low GI diet (diet A) and wholegrain high fibre diet (diet B). Both diets are formulated based on standard pregnancy nutrition recommendations and will ensure adequate supplies of essentials nutrients and vitamins, e.g. iron, zinc, calcium, folate, etc. The diets are also designed to assist the women in optimal BGL control, with carbohydrate restriction. Protein, fat and carbohydrate will make up 15 – 25%, 30 – 35% and 45 – 50% of their daily energy intake respectively. Both diets will emphasize on increasing fibre intake.

The method of allocation concealment used will be sealed opaque envelopes not opened until eligibility is confirmed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomization table created by a computer software (i.e., computerised sequence generation).
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
30/09/2010
Actual
25/02/2011
Date of last participant enrolment
Anticipated
Actual
10/10/2012
Date of last data collection
Anticipated
Actual
Sample size
Target
150
Accrual to date
Final
147
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 257461 0
Government body
Name [1] 257461 0
National Health and Medical Research Council (NHMRC)
Country [1] 257461 0
Australia
Primary sponsor type
University
Name
University of Sydney
Address
Human Nutrition Unit, School of Molecular Bioscience
G08- Biochemistry Building
The University of Sydney NSW 2006
Country
Australia
Secondary sponsor category [1] 256688 0
Individual
Name [1] 256688 0
Professor Jennie Brand-Miller
Address [1] 256688 0
Human Nutrition Unit, School of Molecular Bioscience
G08- Biochemistry Building
The University of Sydney NSW 2006
Country [1] 256688 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 259487 0
Sydney South West Area Health Service Ethics Review Committee (RPAH Zone)
Ethics committee address [1] 259487 0
Research Development Office
Level 3, Building 92
Royal Prince Alfred Hospital
Missenden Road
CAMPERDOWN NSW 2050
Ethics committee country [1] 259487 0
Australia
Date submitted for ethics approval [1] 259487 0
25/08/2010
Approval date [1] 259487 0
01/09/2010
Ethics approval number [1] 259487 0
HREC/10/RPAH/453

Summary
Brief summary
To compare the effects of a low GI diet versus a wholegrain diet during pregnancy in reducing prevalence of large for gestational age infants in women at high risk for developing gestational diabetes. The study hypothesis is that infants born to high risk pregnant women who received low GI dietary advice will have a lower birth weight z-score and percentage body fat than those whose mothers received advice on a macronutrient-matched wholegrain diet.
Trial website
Trial related presentations / publications
Randomized Controlled Trial Investigating the Effects of a Low-Glceamic Index diet on Pregnancy outcomes in Women at High risk of Gestational Diabetes Mellitus: The GI Baby 3 Study. T. Markovic, R. Muirhead, S.Overs, G.P.Ross, J.C.Y.Louie, N.Kizirian, G.Denyer, P.Petocz, J.Hyett and J.Brand-Miller. Diabetes Care July 16, 2015 Electronic copy.
Public notes

Contacts
Principal investigator
Name 31310 0
Prof Jennie Brand Miller
Address 31310 0
Discipline of Nutrition & Metabolism,
School of Molecular Bioscience
Level 6 Charles Perkins Centre D17
The University of Sydney
NSW 2006
Country 31310 0
Australia
Phone 31310 0
+61 2 9351 3759
Fax 31310 0
Email 31310 0
jennie.brandmiller@sydney.edu.au
Contact person for public queries
Name 14557 0
Ros Muirhead
Address 14557 0
The Boden Institute,
Level 2 Charles Perkins Centre D17
The University of Sydney
NSW 2006
Country 14557 0
Australia
Phone 14557 0
+61 478 472 170
Fax 14557 0
Email 14557 0
roslyn.muirhead@sydney.edu.au
Contact person for scientific queries
Name 5485 0
Professor Jennie Brand-Miller
Address 5485 0
Discipline of Nutrition & Metabolism,
School of Molecular Bioscience
Level 6 Charles Perkins Centre D17
The University of Sydney
NSW 2006
Country 5485 0
Australia
Phone 5485 0
+61 2 9351 3759
Fax 5485 0
+61 2 9351 6022
Email 5485 0
j.brandmiller@usyd.edu.au

No information has been provided regarding IPD availability


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
SourceTitleYear of PublicationDOI
EmbaseEffects of a low-glycemic index diet during pregnancy on offspring growth, body composition, and vascular health: A pilot randomized controlled trial.2016https://dx.doi.org/10.3945/ajcn.115.123695
N.B. These documents automatically identified may not have been verified by the study sponsor.