The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
The objective Behavioural Assessment of Breaks in SITting and risk of developing gestational diabetes during pregnancy - the BABy-SIT in pregnancy study
Scientific title
Exploring the relationship of post challenge glucose levels and objectively measured sedentary behaviours in mid-term pregnant women
Secondary ID [1] 292020 0
Universal Trial Number (UTN)
Trial acronym
The BABy-SIT in pregnancy study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pregnancy 303410 0
Gestational diabetes mellitus 303413 0
Condition category
Condition code
Metabolic and Endocrine 302821 302821 0 0
Metabolic disorders
Reproductive Health and Childbirth 302822 302822 0 0
Fetal medicine and complications of pregnancy

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
This is an observational study of sedentary behaviour and sleep patterns in pregnant women attending an outpatient maternity services clinic. Participation involves wearing two small lightweight devices (a sleep monitor and an activity monitor) for a period of 7 days in a 4-week window before the recommended oral glucose tolerance test to screen for gestational diabetes mellitus. The activity monitor (ActivPal) will be worn on the thigh and will provide information on times spent sitting, standing and walking. The sleep monitor (Actigraph) will be worn on the wrist and will provide information on sleeping duration and sleep quality. Participants will choose the timing of the 7-day period within the 4-week window before their oral glucose tolerance test providing that the 7-day period is reflective of their normal weekly schedule.
Intervention code [1] 298151 0
Not applicable
Comparator / control treatment
No control group
Control group

Primary outcome [1] 302205 0
Post challenge glucose levels during a pregnancy oral glucose tolerance test
Timepoint [1] 302205 0
Performed at 24-28 weeks gestation
Primary outcome [2] 302207 0
Total accumulated sedentary time, calculated as an average of the total time spent sitting/lying during waking hours (mins/d), as recorded from 7-days of wearing an ActivPal physical activity monitor
Timepoint [2] 302207 0
Measured between 18-28 weeks gestation
Secondary outcome [1] 335169 0
The frequency of interruptions in sitting, defined as the average number of transitions recorded from “sit/lie” posture to “stand” during waking time, as recorded from 7-days of wearing an ActivPAL physical activity monitor
Timepoint [1] 335169 0
Measured between 18-28 weeks gestation.
Secondary outcome [2] 335170 0
Time accumulated in long duration sedentary bouts, defined as the accumulated time spent in bouts >30minutes (mins/d) during waking hours, as recorded from 7-days of wearing the ActivPAL physical activity monitor.
Timepoint [2] 335170 0
Measured between 18-28 weeks gestation
Secondary outcome [3] 335364 0
Total sleep time, defined as the average time spent sleeping (mins/d), as recorded from 7-days of wearing an Actigraph sleep monitor.
Timepoint [3] 335364 0
Measured between 18-28 weeks gestation.
Secondary outcome [4] 335366 0
Sleep efficiency, defined as the time spent sleeping (mins/d) determined from Actigraph sleep monitor divided by time available for sleep ("lights off to lights on"), multiplied by 100 to calculate a percentage.
Timepoint [4] 335366 0
Measured between 18-28 weeks gestation

Key inclusion criteria
This study will recruit pregnant, English-speaking women, aged 18-50 years at 18-27 weeks gestation.
Minimum age
18 Years
Maximum age
50 Years
Can healthy volunteers participate?
Key exclusion criteria
Criteria for exclusion include - >28 weeks gestation, multiple pregnancy, known diabetes, taking medications known to affect glucose metabolism, and current smokers.

Study design
Natural history
Convenience sample
Statistical methods / analysis
Using data from the UK Pregnancy Better Eating and Activity Trial (UPBEAT), we estimate that 74 individuals will be required with a minimum power of 80% and a type 2 error probability of 0.05 (two-sided test) to determine whether the association of objectively assessed sedentary time and 2-hour glucose differs from zero. To account for participant attrition and potential for missing devices, we will over-sample by 35% and recruit 100 participants.
Multiple linear regression will be used to assess the association between sedentary time (and its interrelationship with sleep) and glucose outcomes (continuous outcome variable), after adjustment for potential confounders (e.g., age, monitor wear time, pre-pregnancy BMI and pregnancy weight gain).
Binary, multivariate logistic regression models, including confounders (age, monitor wear time, pre-pregnancy weight, pregnancy weight gain) and physical activity time, will be used

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 8085 0
Mercy Hospital for Women - Heidelberg
Recruitment postcode(s) [1] 16140 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 296551 0
Government body
Name [1] 296551 0
National Health and Medical Research Council (NHMRC)
Address [1] 296551 0
Level 1
16 Marcus Clarke St
Canberra ACT 2601
Country [1] 296551 0
Primary sponsor type
Professor David Dunstan
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Rd
Melbourne VIC 3004
Secondary sponsor category [1] 295506 0
Name [1] 295506 0
Address [1] 295506 0
Country [1] 295506 0
Other collaborator category [1] 279582 0
Name [1] 279582 0
A/Prof Martha Lappas
Address [1] 279582 0
The Mercy Hospital for Women
4th Floor, 163 Studley Rd
Heidelberg VIC 3084
Country [1] 279582 0

Ethics approval
Ethics application status
Ethics committee name [1] 297765 0
Mercy Hospital for Women HREC
Ethics committee address [1] 297765 0
Human Research Ethics Committee
Mercy Hospital for Women, 6th Floor
163 Studley Rd
Heidelberg, VIC 3084
Ethics committee country [1] 297765 0
Date submitted for ethics approval [1] 297765 0
Approval date [1] 297765 0
Ethics approval number [1] 297765 0

Brief summary
The prevalence of gestation diabetes mellitus (GDM) is increasing worldwide, with current Australian prevalence rates estimated to be between 13-16%. Little is known about how to prevent GDM in high risk individuals. Strategies to date have largely focused on structured exercise programs. However, the results from these trials have shown little success possibly due to low adherence rates. Recently, studies suggest that sedentary behaviour during pregnancy is associated with increased risk for abnormal glucose tolerance, gestational diabetes and preeclampsia. This suggests that strategies that target a reduction in sedentary time could be an additional, or alternative approach to GDM prevention. However, before such interventions are developed, it is important to investigate the associations of objectively measured sedentary time and sleep patterns on blood glucose and GDM risk. This study aims to examine various descriptors of sedentary behaviour (total sedentary time, prolonged sedentary bouts, number of breaks in sitting) which will help to inform the design of early targeted sedentary behaviour interventions to reduce GDM incidence.
Hypothesis: We hypothesise that measurement of sedentary time in pregnant women at 18-28 weeks gestation will be associated with higher fasting and post-challenge glucose levels during the screening test for GDM
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 75046 0
Prof David Dunstan
Address 75046 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Rd
Melbourne VIC 3004
Country 75046 0
Phone 75046 0
+613 8532 1873
Fax 75046 0
+613 8532 1100
Email 75046 0
Contact person for public queries
Name 75047 0
Dr Robyn Larsen
Address 75047 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Rd
Melbourne VIC 3004
Country 75047 0
Phone 75047 0
+613 8532 1859
Fax 75047 0
+613 8532 1100
Email 75047 0
Contact person for scientific queries
Name 75048 0
Dr Megan Grace
Address 75048 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Rd
Melbourne VIC 3004
Country 75048 0
Phone 75048 0
+613 8532-1855
Fax 75048 0
+613 8532-1100
Email 75048 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary