Preventing gestational diabetes in pregnant women with obesity at high risk of gestational diabetes (UPBEAT-TIF)

ISRCTN	ISRCTN11928588
DOI	https://doi.org/10.1186/ISRCTN11928588
EU Clinical Trials Register (EudraCT)	2018-000003-16
Integrated Research Application System (IRAS)	235666
Wellcome Trust grant code	208925/Z/17/Z
Sponsors	King's College London, Guy's and St Thomas' NHS Foundation Trust
Funders	Wellcome Trust, Rosetrees Trust

Submission date: 09/07/2026
Registration date: 19/08/2026
Last edited: 19/08/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Nutritional, Metabolic, Endocrine

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
Gestational diabetes mellitus (GDM) is a common pregnancy complication that occurs more frequently in women with obesity. It can affect the health of both mother and baby and increase the risk of developing type 2 diabetes later in life.

Women are usually screened for GDM between 24 and 28 weeks of pregnancy, but changes associated with GDM may occur much earlier. A prediction tool has been developed to identify pregnant women with obesity who are at high risk of developing GDM in early pregnancy.

This study aimed to investigate whether early intervention could improve blood glucose control in pregnant women with obesity who were identified as being at high risk of GDM.

Who can participate?
Pregnant women aged 18 years or over with a body mass index (BMI) of 30 kg/m² or higher, carrying a single baby and between 11 and 14+6 weeks of pregnancy, who were identified as being at high risk of developing gestational diabetes.

What does the study involve?
Participants were screened using a prediction tool to identify those at high risk of GDM.

Women identified as high risk were randomly allocated to one of three groups:
- Lifestyle intervention including dietary and physical activity advice
- Lifestyle intervention plus metformin treatment
- Standard antenatal care

The lifestyle intervention was delivered over 8 weeks and focused on reducing dietary glycaemic load and saturated fat intake, increasing physical activity and reducing sedentary behaviour.

Participants attended assessments at the start of the study and after approximately 8 weeks. These included:
- Continuous glucose monitoring
- Dietary assessments
- Physical activity monitoring using a wrist-worn accelerometer

Researchers also collected information on gestational diabetes diagnosis, maternal health and pregnancy outcomes, and newborn health outcomes.

What are the possible benefits and risks of participating?
Participants may have benefited from additional monitoring and support to improve their blood glucose control during pregnancy. The findings may help improve future strategies for preventing gestational diabetes in women with obesity.

Participants allocated to the metformin group may have experienced side effects associated with the medication. The study also involved wearing a continuous glucose monitor, completing questionnaires and attending study assessments.

Where is the study run from?
St Thomas' Hospital, London, UK.

When is the study starting and how long is it expected to run for?
May 2021 to December 2024.

Who is funding the study?
1. Wellcome Trust, UK.
2. Rosetrees Trust, UK.

Who is the main contact?
Dr Sara White, sara.white@kcl.ac.uk

Contact information

Dr Sara White
Public, Scientific, Principal investigator

Department of Women and Children's Health
King's College London
10th Floor North Wing
St Thomas' Hospital
Westminster Bridge Road
London
SE1 7EH
United Kingdom

Email	sara.white@kcl.ac.uk

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Open (masking not used)
Control	Active
Assignment	Parallel
Purpose	Prevention
Scientific title	Prevention of gestational diabetes in obese pregnant women; a proof of principle study targeting early pregnancy intervention to women at risk
Study acronym	UPBEAT-TIF
Study objectives	To assess in obese pregnant women at high risk of GDM the efficacy of a) lifestyle advice, b) metformin treatment plus lifestyle advice to improve maternal glycaemic control when compared with c) standard care. To assess feasibility of risk assessment for GDM using a new prediction tool in obese women, to determine the impact of each intervention on a targeted maternal metabolome, to examine the effect of each intervention on dietary intake and physical activity.
Ethics approval(s)	Approved 06/11/2018, London - West London & GTAC Research Ethics Committee (The Old Chapel, Royal Standard Place, Nottingham, NG1 6FS, United Kingdom; +44 (0)207 104 8098; NRESCommittee.London-WestLondon@nhs.net), ref: 18/LO/1500
Health condition(s) or problem(s) studied	Prevention of gestational diabetes mellitus (GDM) in pregnant women with obesity identified as being at high risk of developing GDM.
Intervention	Participants were randomised 1:1:1 to one of three groups: (1) lifestyle intervention consisting of dietary and physical activity advice delivered over 8 weeks; (2) lifestyle intervention plus metformin, initiated at 500 mg daily and titrated up to a maximum dose of 2000 mg/day; or (3) standard antenatal care. The lifestyle intervention focused on reducing glycaemic load, reducing saturated fat intake, increasing physical activity and reducing sedentary behaviour.
Intervention type	Mixed
Primary outcome measure(s)	Mean 24-hour glucose concentration measured using continuous glucose monitoring (Dexcom G6 CGM) at baseline (13-15+6 weeks’ gestation) and follow up (22-25 weeks' gestation)
Key secondary outcome measure(s)	Mean daytime glucose (07:00 - 23:00 h, mmol/L), mean nocturnal glucose (23:00 - 07:00 h, mmol/L), time in range: % time within 3.5 - 6.7 mmol/L and 3.5 - 7.8 mmol/L , time above range: % time above 6.7 mmol/L and above 7.8 mmol/L , time below range: % time below 3.5 mmol/L (TBR), glucose variability: standard deviation (SD) and coefficient of variation (CV) measured using continuous glucose monitoring (Dexcom G6 CGM) at baseline (13-15+6 weeks’ gestation) and follow up (22-25 weeks' gestation) GDM diagnosis at 24 - 28 weeks' gestation, according to IADPSG and NICE criteria, measured using the diagnosis of gestational diabetes mellitus using a 75 g oral glucose tolerance test at 24–28 weeks’ gestation Dietary intake measured using a semi-quantitative food frequency questionnaire, including glycaemic index, glycaemic load, saturated fat intake and other dietary variables, at baseline at 13–15+6 weeks’ gestation and follow-up at 22–25 weeks’ gestation Physical activity measured using a wrist-worn accelerometer at baseline at 13–15+6 weeks’ gestation and follow-up at 22–25 weeks’ gestation Maternal outcomes, including gestational diabetes, hypertensive disorders, mode of delivery, pregnancy complications and hospital admission, and neonatal outcomes, including gestational age at birth, birthweight, birthweight centile, neonatal complications and neonatal unit admission, measured using data obtained from medical records at delivery and 4-weeks postpartum
Completion date	31/12/2024

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	18 Years
Upper age limit	99 Years
Sex	Female
Target sample size at registration	84
Total final enrolment	60
Key inclusion criteria	1. Women over 18 years of age 2. BMI ≥ 30 kg/m² 3. Singleton pregnancy 4. Gestational age between 11 and 14+6 weeks’ gestation 5. Willing and able to give informed consent
Key exclusion criteria	1. Insufficient understanding of the trial 2. Inability to provide informed consent 3. Pre-existing diabetes 4. HbA1c ≥ 6.5% 5. Hypertension requiring treatment before or during pregnancy 6. Thyroid disease 7. Coeliac disease 8. Systemic lupus erythematosus 9. Antiphospholipid syndrome 10. Renal disease 11. Thalassemia 12. Sickle cell disease 13. Current psychosis 14. Current metformin treatment 15. Use of medications affecting insulin sensitivity 16. Use of other oral hypoglycaemic medications 17. Steroid treatment 18. Antipsychotic medication use 19. Previous bariatric surgery 20. Multiple pregnancy 21. Participation in another IMP trial 22. Contraindication to metformin 23. Low risk of gestational diabetes according to screening assessment
Date of first enrolment	20/05/2021
Date of final enrolment	28/10/2024

Locations

Countries of recruitment

United Kingdom
England

Study participating centre

St Thomas' Hospital

Department of Women and Children's Health, 10th Floor North Wing, St Thomas' Hospital, Westminster Bridge Road
London
SE1 7EH
England

Results and Publications

Individual participant data (IPD) Intention to share	No

Editorial Notes

16/07/2026: Study's existence confirmed by Health Research Authority (HRA) (UK).