Vitamin D and lifestyle Intervention for gestational diabetes mellitus (GDM) prevention
Gestational diabetes is high blood sugar that develops during pregnancy. It can cause health complications for both the mother and her developing baby. Women who have a higher body weight before pregnancy face a greater risk of developing this condition. The DALI study aims to find practical ways to prevent gestational diabetes from developing. Women who are under 12 weeks pregnant and have a body mass index (BMI) of 29 or higher can take part. Participants are placed into different groups by chance. Depending on their group, women receive personal coaching on healthy eating, guidance on safe physical activity, daily vitamin D supplements, or a combination of these. Researchers monitor blood sugar levels and weight gain across the pregnancy to see which approach works best. The findings will help doctors improve antenatal care across the UK and Europe.
At a glance
What is this study about?
Gestational diabetes happens when your body cannot produce enough insulin during pregnancy. Insulin is a natural hormone that keeps blood sugar levels balanced. When blood sugar stays too high, it can lead to complications such as having an unusually large baby, needing a Caesarean birth, or developing high blood pressure.
Women who carry extra weight before pregnancy have a higher chance of developing gestational diabetes. Finding simple, safe ways to stop this condition from happening can protect the health of both mother and baby. Because of this, researchers created the DALI study across several European maternity hospitals, including Cambridge University Hospitals in the UK.
The trial tests three main approaches: eating a balanced diet, staying physically active, and taking vitamin D supplements. Vitamin D supports bone health and may also help the body manage blood sugar properly. By providing one-to-one coaching and regular health checks, researchers want to see if these everyday changes can effectively protect mothers-to-be.
Key takeaways
- Aims to prevent gestational diabetes in women with a pre-pregnancy BMI of 29 or more.
- Tests healthy eating guidance, physical activity coaching, and daily vitamin D supplements.
- Open to women who are less than 12 weeks pregnant with a single baby.
- Involves one-to-one coaching sessions and health checks until birth.
- Participation is voluntary and runs alongside your normal antenatal care.
Who may be eligible?
You may be able to join this study if you are 18 or older and in the first 12 weeks of your pregnancy. Your body mass index (BMI) before pregnancy needs to be 29 or higher. You must be able to do moderate physical activity, such as walking at least 100 metres safely, and plan to have your baby at one of the participating maternity hospitals.
You will not be able to take part if you already had diabetes before becoming pregnant, or if initial blood tests show your blood sugar is already elevated. The study is also not suitable for women expecting twins or triplets.
Finally, women with complex dietary requirements, severe kidney or heart conditions, significant mental health conditions, or known problems with calcium metabolism cannot join.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- Are you aged 18 or older?
- Are you currently less than 12 weeks pregnant?
- Was your body mass index (BMI) 29 or higher before pregnancy?
- Are you expecting a single baby (not twins or triplets)?
- Can you comfortably walk at least 100 metres?
- Are you free from pre-existing diabetes and calcium disorders?
What does participation involve?
If you take part, you will be randomly assigned by a computer to one of several treatment groups. If your group includes lifestyle support, you will meet with a lifestyle coach for five in-person sessions and three phone calls to discuss healthy meals and safe exercise. If your group includes vitamin D, you will take daily supplements until your baby arrives.
You will attend health checks at the start of the study, between 24 and 28 weeks of pregnancy, and between 35 and 38 weeks. During these visits, researchers will check your weight and take routine blood and urine samples to measure your blood sugar, insulin, and calcium levels. Your participation lasts from your first trimester until you give birth.
Potential risks and benefits
Locations (1)
- Addenbrooke's Treatment CentreApproximateCambridge, England
Common questions
What is gestational diabetes?
It is a type of high blood sugar that develops during pregnancy and usually disappears after the baby is born.
Are the vitamin D supplements safe for my baby?
Yes. The trial uses carefully regulated doses of vitamin D that are considered safe to take during pregnancy.
Do I have to pay to take part?
No. All lifestyle coaching sessions, study supplements, and trial-related health checks are completely free.
Can I pick which group I want to join?
No. A computer randomly assigns participants to groups so researchers can make a fair and accurate comparison.
Can I leave the study if I change my mind?
Yes. You are free to stop taking part at any time, and your standard NHS maternity care will continue as normal.
How to find out more
David Simmons
Always speak to your GP or specialist before deciding to take part in a study.
Discussion
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