What is gestational diabetes? 

Gestational diabetes (GD) is diabetes that develops during pregnancy. It means that you have high sugar levels in your bloodstream. Whilst it can occur at any time, it usually develops during the second or third trimester.

Our bodies use glucose or sugar for energy. If we eat more sugar than we need, our bodies release the hormone insulin to help remove it. The more sugar we consume, the more insulin we need. 

Gestational diabetes may occur if our bodies don’t produce enough insulin to process the glucose level in our bloodstream. Or it could be that we experience insulin resistance; We have plenty of insulin, but it doesn’t lower our blood sugar levels effectively. Pregnancy hormones can impact how effectively insulin works. 

How common is it? 

4-5 in 100 women will develop gestational diabetes during pregnancy. Whilst anyone can develop it, some risk factors make it more likely. These include: 

  • BMI greater than 30
  • Family history of diabetes (parent or sibling)
  • Experienced GD in a previous pregnancy
  • Large baby in a previous pregnancy, heavier than 4.5kg (10lb) 
  • Have polycystic ovary syndrome (PCOS)
  • Certain ethnicities (regardless of country of birth): South Asian, Black, African-Caribbean or Middle Eastern.

If you meet any of these criteria, you will be offered GD screening during pregnancy. Including a blood test in early pregnancy and a Glucose Tolerance Test when you are 24-28 weeks pregnant.

If you don’t meet these criteria, your midwife will also be testing the glucose level when she takes a urine sample during routine antenatal appointments. If this is high, she may recommend testing for gestational diabetes.

What are the symptoms of gestational diabetes? 

Not everyone experiences symptoms, as routine screening usually picks it up first. However, you may experience these symptoms if your blood sugar level gets too high, known as hyperglycaemia. These include: 

  • Increased thirst
  • Dry mouth
  • Needing to pass urine more frequently than normal
  • Feeling more tired than normal
  • Blurred vision
  • Feeling shaky
  • Nausea when hungry

What is the treatment? 

Maintaining a healthy blood sugar level is the most crucial thing if you have gestational diabetes. The specialist team who look after you will give you lots of helpful information on how to do this. The key elements are: 

  • Staying active 
  • Eating healthy foods 
  • Maintaining a healthy weight
  • Medication, if necessary

Staying active

Being active encourages our muscles to use any additional glucose for energy, removing it from our bloodstream and lowering our blood sugar levels. It also helps our bodies use insulin more effectively – possibly reducing the amount you need if your doctor has prescribed it.  

Pregnancy is not the time to introduce ambitious new exercise routines; going out for a 30-minute walk (or two 15-minute walks) is a great place to start. Why not meet up with a friend, listen to a podcast or simply enjoy the benefits of being in nature! 

Eating healthily

Diet is one of the most effective ways to manage your blood sugar levels. There are a few key things you can start doing straight away: 

  • Cut down on your sugar intake 
  • Reduce your portion size
  • Swap in healthier carbohydrates, e.g. wholemeal bread, brown rice or pasta, sweet potatoes

There are two lifestyle diets (rather than weight loss diets) that can help you too: 

Low-GI (Glycaemic Index)

Low-GI foods take the body longer to break down, so you are unlikely to experience blood sugar spikes that foods such as white bread or cake may create. 

Find out more about low-GI foods here: The Association of UK Dieticians.

DASH (Dietary Approaches to Stop Hypertension)

Research shows that following the DASH diet can help people with diabetes and gestational diabetes. This is because GD increases the likelihood of women experiencing high blood pressure or developing pre-eclampsia. The focus is on eating plenty of fruit, vegetables, whole grains and lean meats. Find out more about the DASH diet here: Healthline.  

Finally, Diabetes UK provide lots of information about the types of foods to support healthy blood sugar levels and those to avoid: Diabetes UK.

You may also find these articles useful: 

Maintain a healthy weight

It is important not to diet during pregnancy as both you and your baby need a healthy supply of nutrients. Instead, as discussed above, maintain a healthy weight by making healthier food choices and getting out for at least 30 minutes of exercise each day. 


You may need medication, including metformin and insulin depending on blood sugar levels. Your doctor will discuss this with you.

What is the impact on maternity care? 

If you are diagnosed with gestational diabetes, alongside your community midwife, there will be a team of specialists looking after you. Depending on your NHS Trust, this may include some of the following people: 

  • Specialist midwife (diabetes or clinic lead)
  • Doctor who specialises in diabetes (endocrinologist or diabetologist)
  • Obstetrician
  • Diabetes nurse
  • Diabetes dietician

This team of specialists will advise you on how best to manage your blood sugar levels within a healthy range. This advice will cover your diet and healthy eating tips, exercise, healthy weight management and how to adapt your birth preferences. 

You will also have additional antenatal appointments and ultrasound scans to help track how quickly your baby is growing and ensure you’re both healthy. 

What does it mean for labour and birth? 

If you develop gestational diabetes during pregnancy, your midwife or doctor may advise you to have your baby early, ideally, between 38 and 41 weeks. This will either be via induction of labour or caesarean section. 

If your blood sugar levels are stable and your maternity team is happy that your baby is healthy and well, they may be happy for your pregnancy to go to term. They will discuss the benefits and risks of your options so you can make an informed decision that suits your circumstances. The B.R.A.I.N. decision-making tool is useful for these discussions. 

During labour, your midwife will monitor your blood sugar levels each hour to make sure they’re within a safe level. They may offer you an insulin or glucose drip if they need adjusting. 

Regardless of how you give birth, the safest place for you and your baby is the obstetric unit in the hospital. There are a couple of reasons why. Firstly, so that your midwife can continuously monitor your baby’s heart rate using a Cardiotocograph (CTG) to confirm they’re coping well with labour. Secondly, because the doctors and equipment are close by should you or your baby need any additional help during labour and birth. 

How can gestational diabetes affect my baby? 

Most women who develop gestational diabetes will have healthy babies. However, GD can mean babies grow bigger more quickly than expected, which may impact how they are born. This additional growth is due to excess glucose crossing the placenta and causing the baby to produce more insulin to process it. As the baby gets more energy than they need to grow and develop, this excess energy is stored as fat. A big baby is 4.5kg (10lb) or heavier. The medical term is macrosomia.

Other risk factors include:

  • Premature birth (natural or by recommendation due to size)
  • Polyhydramnios (excess amniotic fluid)
  • Intrauterine growth restriction (IUGR), when baby’s growth slows down or stops during pregnancy
  • Shoulder dystocia
  • Low blood sugar levels at birth (hypoglycaemia)
  • Stillbirth or neonatal death, if GD is not diagnosed or not treated (uncommon)
  • Breathing difficulties, needing assistance when born.
  • Obesity in childhood
  • Type 2 diabetes in later life

Managing blood sugar levels in pregnancy and during labour reduces the likelihood of these risk factors for the baby. 

How long does gestational diabetes last?

The good news is that gestational diabetes usually disappears after birth as pregnancy hormones leave your body and your insulin processes excess glucose effectively again. 

However, there can be some longer-lasting impacts. For example: 

  • Having had gestational diabetes in one pregnancy does increase your likelihood of developing it again in subsequent pregnancies. 
  • You have a 1 in 2 or 50% chance of developing type 2 diabetes within the next 5-10 years. 

You will be offered a blood test for diabetes between 6 to 13 weeks after giving birth. If this is negative, your GP will advise you to have an annual blood test for diabetes each year.  

You can reduce these risks by sticking to the health advice for reducing the impact of gestational diabetes: 

  • Healthy eating
  • At least 30 minutes of exercise a day
  • Maintaining a healthy weight

Support for GD

If you are worried about gestational diabetes, speak to your community midwife. You can also call the Diabetes UK helpline (Monday-Friday, 9-6pm):

  • England, Wales & Northern Ireland: 0345 123 2399
  • Scotland: 0141 212 8710 
  • Email: [email protected] 

Another useful website is: Gestational Diabetes UK

Content Disclaimer

The information contained above is provided for information purposes only. The contents of this article are not intended to amount to advice, and you should not rely on any of the contents of this article. Professional advice should be obtained before taking or refraining from taking any action as a result of the contents of this article. New Life Classes disclaims all liability and responsibility arising from any reliance placed on any of the contents of this article.


Campbell A. P. (2017). DASH Eating Plan: An Eating Pattern for Diabetes Management. Diabetes spectrum : a publication of the American Diabetes Association, 30(2), 76–81. https://doi.org/10.2337/ds16-0084

Diabetes UK, ‘What is gestational diabetes

Healthline, ‘The complete beginners guide to the DASH diet’https://www.healthline.com/nutrition/dash-diet

NHS ‘Overview of gestational diabetes

NICE Guideline NG3 (2020),’Diabetes in pregnancy: management from preconception to the postnatal period

Royal College of Obstetricians and Gynaecologists (RCOG) ‘Gestational diabetes

Tommy’s ‘Gestational Diabetes

The Association of UK Dieticians, ‘Glycemic Index: Food fact sheet