About gestational diabetes (GDM)
Gestational diabetes (GDM) is a form of diabetes that occurs in pregnancy. It affects women who do not already have another type of diabetes.
It is usually diagnosed at about week 28 of the pregnancy, but can be picked up at any time. It affects about 1 in 5 women at Kingston Hospital.
GDM occurs because your body cannot produce enough insulin (a hormone) to keep your blood glucose levels within the target range.
In pregnancy your body can become resistant to insulin due to hormonal changes. As a result, your blood glucose levels become higher.
Most women who have GDM have healthy pregnancies and healthy babies.
Effects of GDM
The most common effects of GDM are as follows.
Effects on you
Urinary tract infections (UTIs). These are more common in women with gestational diabetes. They are caused by bacteria, which grow when blood glucose levels are above range.
Too much amniotic fluid (polyhydramnios). Amniotic fluid is the liquid surrounding your baby. Too much amniotic fluid can cause your baby to be born too soon.
Effects on your baby
Large baby (macrosomia). When your blood glucose levels are above range too often, the extra sugar passes to your baby. Your baby can make its own insulin and store the extra sugar. This makes them grow larger, and fat is deposited around their tummy and shoulders. This can make it difficult for you to deliver your baby and increase the risk of premature delivery.
| Keeping most of your blood glucose levels in target range can lower the risk of your baby having problems. |
If you have gestational diabetes, this does not mean your baby will be born with diabetes. Your baby can develop low blood sugars for a short period (approximately 24 hours) after delivery. This is known as hypoglycaemia.
Your midwives will check your baby for this effect after birth. Treatment is by regular feeding.
Monitoring your blood glucose
We have given you a blood glucose monitor. Before you start using your monitor, watch this online video to learn how to check your blood sugars.
You must keep testing your blood glucose throughout your pregnancy. You must do this even if your levels are within the target range. This is because your levels may change as your pregnancy progresses.
We will review your blood glucose levels at each antenatal appointment.
Try to follow the dietary advice we give you. This will help keep your levels within target.
When to check
You must check your blood sugars 4 times every day, as follows.
| When to take a monitor reading | Reading should be |
|---|---|
| When you wake, or as soon as possible after waking. | Less than 5.3mmol/l |
|
One hour after:
|
Less than 7.8mmol/l |
Tips for using the monitor
- Before testing, always wash your hands in warm water and dry them properly.
- Let your hand fall loosely at your side for at least 10 seconds before your prick your finger. This allows your blood to flow into your fingers.
- Use the outside edges of your finger to prick into.
- When you have pricked your finger, do not squeeze it. Let it hang loosely at your side for 10 seconds. Squeeze the finger from the palm down towards the end of the finger. This will encourage it to bleed.
- Make sure you have enough blood on the end of your finger. If you do not have enough, the monitor may give an inaccurate result.
Monitor results
Within range
If your blood glucose levels are within the target range and stay within it, you do not need further treatment. If they stay within range regularly, we may suggest you test them less often.
Above range
If your blood glucose levels are above target, you may need to start Metformin tablets or insulin (by injection). This will help lower your levels for the duration of your pregnancy.
We will discuss this with you at your antenatal appointment.
After your pregnancy
GDM usually goes away after pregnancy. To make sure, we will ask your GP to offer you the following:
- a blood test at your 6 to 8 week postnatal appointment
- an annual blood test to check your risk of developing prediabetes or type 2 diabetes.
| You need to contact the GP surgery yourself, to book these appointments. |
If we have given you Metformin or insulin treatment during your pregnancy, we will stop this treatment as soon as your baby is born.
Future pregnancy
GDM is likely to occur in any future pregnancy. If you become pregnant again, we will offer you an early Glucose Tolerance Test at 16 weeks. If the result is negative, we will repeat this at 28 weeks.
Future health effects
Women with GDM have an increased risk of developing type 2 diabetes during their lifetime. (Up to 60% of women, compared to 10% in the general population).
To help reduce your risk of developing prediabetes or type 2 diabetes later in life, we advise you to do the following.
- Ask your GP for an annual blood test to check your blood sugar levels.
- Keep eating a healthy diet, to manage your blood sugar levels.
- Keep physically active and maintain a healthy weight.
Eating
- Try and eat as healthily as you can. It can make you feel more energised and help manage blood sugar levels. When you are ready, and your healthcare team say it is safe to do so, you can make small dietary changes to lose small amounts of excess weight. For tips, read Diabetes UK information on healthy eating tips for lowering type 2 risk and healthier snacks.
- Even small amounts of weight loss can help reduce fat in and around your liver and pancreas. This will help to manage your blood sugar levels.
- Do not try to lose weight too quickly, especially if you are breastfeeding.
Exercising
- Try to do a little more physical activity each day to help your body become more responsive to insulin. Any activity that makes you slightly out of breath is beneficial (for example Hoovering or going up and down stairs). For tips, read Diabetes UK information on exercise.
- Try to include your family in healthy eating and regular exercise, so you can do it together. Your children will have an increased risk of type 2 diabetes later in life, so a healthy lifestyle will help lower their risk.
- If you’re a healthy weight for your height, you can still be at risk of prediabetes or type 2 diabetes. Small dietary changes and a little more exercise will help lower your risk.
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Check with your GP before making significant changes to your diet, losing weight or trying a new physical activity. Your GP may be able to refer you to a type 2 diabetes prevention course or weight-loss support service. They can also offer type 2 prevention advice. |
Healthier You programme
Healthier You is an NHS diabetes prevention programme. It identifies people at risk of developing type 2 diabetes and refers them onto a 9-month lifestyle change programme.
You can take part in person or online.
- If you take part in person, you will receive tailored support to manage your weight, eat more healthily and be more physically active.
- If you take part online, you will receive similar support through the a mix of wearable devices, phone apps and peer support online groups. These will help you monitor your exercise levels, access health coaches and set personal goals.
Research shows that the Healthier You NHS Diabetes Prevention Programme has cut the number of people being diagnosed with type 2 diabetes in England. For people completing the 9-month programme, it reduces the risk by more than 30%.
To find out more visit Healthier You or call 0333 047 9999.
Contact information
Kingston Hospital Diabetes Midwives, Monday to Friday 8am to 6pm