Gestational Diabetes

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Gestational Diabetes Mellitus (GDM)

Gestational diabetes is a type of diabetes that can develop during pregnancy. It affects those who are not already diagnosed as having Type 1 or Type 2 diabetes.

Gestational diabetes develops because of an interaction between your pregnancy hormones and the natural insulin made in your body.  This means you have high blood sugar and need to take extra care of yourself and your bump. This will include eating well and keeping active. Gestational diabetes usually goes away again after giving birth.

Testing for GDM

GDM is usually diagnosed by a blood test performed between 24 and 28 weeks into pregnancy, called a glucose tolerance test (GTT).  When you have your first appointment with a midwife, it will be determined if you require a GTT as some people will have an increased chance of developing GDM.  If you are told a GTT would be advised, an appointment will be requested and you will receive this appointment by post.

The test involves having a sample of blood taken early in the morning. You must not eat anything the night before.  After the blood test you will be given a sweet drink. Two hours later, another blood sample will be taken.  Bring a book!!

It is advised you don’t go for a walk during the two hours between your samples as this will burn off the sugar in the sweet drink more quickly and may result in an inaccurate result.  We also advise not smoking/vaping or chewing gum before or during the test.

If your result is normal, you probably will not hear from your midwife – no news is good news! However, if your result tells us you do have GDM, we will call you..  You should receive this call within seven days of your test.

What Happens if You Have GDM

If your GTT result confirms you have gestational diabetes, you will get a call from the Diabetes Specialist Midwives.  They understand this is a scary diagnosis, but they will offer you reassurance and explain what the diagnosis means for your care.

They will invite you to meet with them at the hospital to discuss how GDM can be managed and will put an individualised plan of care into place.  They will discuss dietary changes that will help to maintain healthy blood sugars, discuss medications that are available if needed and provide you with a blood glucose meter which you will use at home to monitor your blood sugars.

You will also be offered regular scans, which look at how your baby is growing from 28 weeks of your pregnancy. You will also be given regular appointments with the Diabetes Specialist Midwives to review your blood sugars.  At each appointment, they will answer your questions, make a plan for your ongoing care and make changes to your plan of care if needed.

The Diabetes Specialist Midwives will also call you during your pregnancy to catch up with you and see how you are getting on.  You will be given their number so you can call if you need extra support or have questions.

Find out what it was like for Roisin to find out she had gestational diabetes

Please be aware that your local hospital will explain what your blood glucose targets are which may differ from those mentioned in the film.

Find out about Rei’s experience with gestational diabetes

How does GDM affect your labour?

Having GDM should not affect how you have your baby.  You can still have a vaginal birth or a caesarean birth if that is your preferred option.  However, it is recommended you have your baby in hospital.

Having GDM can affect the timing of your labour.  If you are maintaining healthy blood sugars and your baby is growing as expected, it is recommended your baby arrives no later than 40 weeks and 6 days.  However, if you are prescribed medication to help your blood sugars, this changes to 39 weeks.  If your baby has not arrived by this time, you may be advised to have an induction, which will bring on labour, or a caesarean birth.

During labour your blood sugars will be checked every hour.  This is to make sure they are not falling outside of the healthy range.

What happens after your baby is born?

As soon as your baby is born, you will no longer be treated as having diabetes.  Yes! It really does just disappear!  You may have one random blood sugar test after the baby arrives, but otherwise, you no longer have to test your blood sugars. You can stop any medication you may have been prescribed, and you can eat normally again. However, you are advised to follow a healthy diet which is not continually high in carbohydrate.

Your baby will, however, need some checks to make sure they have made the changes needed to regulate their own blood sugars.  Babies of diabetic mothers can experience very low blood sugars, so it is recommended you both stay with us for around 24 hours to ensure your baby is well.

After having GDM, in any or all of your pregnancies, it means you have an increased risk of developing Type 2 Diabetes later in life.  This is why it’s important to follow a healthy diet. Remember that carbohydrate isn’t just sweets and cakes, it’s also in starchy foods such as potatoes, bread, pasta and rice. Your diet doesn’t have to be completely ‘fun free’, but it helps to limit these foods and watch your weight.

As you are at increased risk, you will be offered a blood test at your GP surgery (called an HbA1c) three months after your baby is born.  This will check your blood sugars are back to normal.  This same test should then be performed every year for the rest of your life. You may be eligible for a local service called ‘Healthier you’ which is a free, personalised program to help you reduce your risk of type 2 diabetes. Your GP or nurse can refer you after your HbA1c blood test.

Will this affect your future pregnancies?

If you go on to have further pregnancies, you will be at an increased chance of developing GDM again.  Because of this, you will be offered a GTT in the first three months of your new pregnancy.  If this test is normal, the GTT will be repeated at 24-28 weeks. If the first GTT shows you have GDM, you will be referred to the Diabetes Specialist Midwife early.

If you are considering becoming pregnant, you are advised to adopt a healthy diet and lifestyle whilst trying to conceive and, once pregnant, you should register your new pregnancy with your local maternity care providers early.

Healthy Eating for Gestational Diabetes

There are five main principles for managing gestational diabetes:

  • Eat regular meals
  • Eat a varied and balanced diet (as for any pregnancy)
  • Take care with your choice of starchy foods – choose higher fibre and watch your portion sizes
  • Cut down on food and drinks containing sugar
  • Do some physical activity every day

Eat regular meals

Spreading your food intake over the whole day helps your body to keep your glucose levels more stable. Eat three meals each day (breakfast, lunch and evening meal). Try to have three medium-sized meals rather than one or two small meals and one large meal. You may need to aim for 30g of carbohydrate and include protein with carbohydrate in your meal as this will help lower your blood glucose level after eating.

Can I include snacks?

There will be times when you are hungry and want something to eat without it affecting your blood glucose level or requiring another injection (if you are on insulin).

Snacks that contain carbohydrates (carbs) will make blood glucose levels rise, but how much depends on the amount. The more carbs you eat; the higher the rise in your blood glucose level.

As a guide, snacks containing up to 10g carbs will raise blood glucose levels by up to 3 mmol/l, which is not a large amount. Reading labels and finding out how much carbohydrate is in your snack will help you with your management.

Managing snacks

  • Carb free or up to 10g carbs = No action.
  • If you are diet-controlled, on tablets, injecting insulin twice a day you need to keep snacks carb-free or up to 10g carbs maximum.

Eating more than 10g carb

If you use rapid-acting insulin, such as NovoRapid or Humalog, you can eat more than 10g carbs but you will need some insulin with it. Count the carbs by looking at the label. The Carbs and Cals book/app is also a helpful guide.

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