If you have gestational diabetes, you will be advised about monitoring and controlling your blood glucose (sugar) levels.
For many women, changing diet and more exercise will be enough to control your gestational diabetes. Some women will need medication.
In addition, you will be taught how to monitor your blood glucose, and your unborn baby will be closely monitored.
Monitoring blood glucose
Your GP, midwife, or diabetes team will discuss with you how to test your blood glucose levels. They will also explain how blood glucose is measured, and what level you should be aiming for.
Blood glucose levels are usually measured in terms of the amount of millimoles of glucose in one litre of blood. A millimole is a measurement that defines the concentration of glucose in your blood. The measurement is expressed as millimoles per litre, or mmol/l for short.
Your individual mmol/l target will be set for you. This may include a target for your:
fasting blood glucose (after you have not eaten for around eight hours - normally first thing in the morning)
- postprandial blood glucose (one hour after you have eaten)
You will be advised when and how often you need to test your blood glucose. You may need to test your fasting blood glucose and your blood glucose after every meal throughout your pregnancy. If your diabetes is being treated with insulin (see below, under Medications), you may need to test your blood glucose before going to bed at night.
Read about testing your glucose levels for more information about how to do this.
You may be advised to change your diet to control your gestational diabetes. You should be referred to a dietician (a healthcare professional who specialises in nutrition) to advise on a special diet.
Some advice you may be given is explained below.
Don't skip meals. By eating regular, balanced meals which include a starchy carbohydrate with a low Glycaemic Index (GI) you can absorb carbohydrate more slowly helping keep your blood glucose levels stable between meals.
Choose from pasta, basmati or easy cook rice, grainy breads such as granary, pumpernickel and rye, new potatoes, sweet potato and yam, porridge oats, All-Bran and natural muesli. High fibre varieties of starchy foods will also help your digestive system and prevent constipation.
The GI ranks food based on its effect on blood sugar levels - with low GI foods absorbed into the bloodstream slowly, and high GI foods absorbed quickly, causing blood sugar levels to rise.
Don't get obsessed with GI ratings. Aim for a balanced and appealing diet, which you can keep to over time. Think variety to get the full benefits of low GI foods.
Read about the Glycaemic Index at Diabetes UK for more information.
Eat more fruit and vegetables
Aim for at least five portions a day to provide vitamins, minerals and fibre but keep to one portion of fruit at a time. And try to include beans and lentils such as kidney beans, butter beans, chickpeas or red and green lentils. Sound advice and tasty recipes are available from Diabetes UK.
Limit sugar and sugary foods
You don't need to eat a sugar-free diet. Sugar can be used in foods and in baking as part of a healthy diet, but use it sparingly. Drinking sugar-free, no added sugar or diet colas or squashes, instead of sugary versions can reduce the sugar in your diet.
You may also be advised to choose lean (not fatty) proteins, such as fish. Eat two portions of fish a week, one of which should be oily fish, such as sardines or mackerel. There are some fish you should avoid, for example, eating too much tuna. Read about foods to avoid in pregnancy for more information.
Aim to eat a balance of polyunsaturated and monounsaturated fats. Small amounts of unsaturated fat will keep your immune system (the body's defence system) healthy and can reduce cholesterol levels (cholesterol is a fatty substance that can build up in your blood and seriously affect your health).
Foods that contain unsaturated fat include:
nuts and seeds
- spreads made from sunflower, olive and vegetable oils
If your body mass index (BMI) was more than 27 before you became pregnant, you may be advised to reduce the amount of calories in your diet. You can use the healthy weight calculator to work out your BMI - but remember to use your pre-pregnancy weight.
Your GP, midwife, or diabetes team will advise how many calories you should eat a day, and the safest way to cut out calories from your diet.
Physical activity lowers your blood glucose level, so regular exercise can be an effective way to treat gestational diabetes. Your GP, midwife, or diabetes team will advise about the safest way to exercise during pregnancy. Read about exercise in pregnancy for more information.
If your body mass index (BMI) was more than 27 before you became pregnant, you may be advised to take moderate exercise for at least 150 minutes (2 hours and 30 minutes) every week. This can be any activity that gets you slightly out of breath and raises your heart rate, such as cycling or fast walking.
If diet and exercise have not effectively controlled your gestational diabetes after around one to two weeks, you may be prescribed medication. The timing may vary depending on your glucose levels.
There are several different types of medication available, and the choice will depend on:
- what will most effectively control your blood glucose
- what is acceptable to you
Possible medicines include:
These are explained in more detail below. These medicines will be stopped immediately after the birth of your baby.
If you are insulin resistant (your body does not respond to insulin), you may need insulin injections to ensure your body has enough insulin to lower your blood glucose levels.
Insulin must be injected because if you swallowed it, the enzymes (proteins that speed up and control chemical reactions in the body) in your stomach would digest it like a food, and it would not be effective. If you need insulin injections, you will be shown:
- how and when to inject yourself
- how to store your insulin and dispose of your needles properly
Insulin comes in several different preparations.You may be prescribed:
- Rapid acting insulin analogues (aspart or lispro) - these are normally injected before or just after meals; they work quickly but do not last long
- Basal insulin (insulatard or lantus) - these are normally injected at bedtime or on waking; they provide the background insulin required to keep blood glucose levels stable between meals
These are safe to use during pregnancy. However, you will need to monitor your blood glucose closely. If you are being treated with insulin, you will need to check your:
- fasting blood glucose (after you have not eaten for around eight hours - normally first thing in the morning)
- blood glucose, one hour after every meal
- blood glucose at other times (for instance if you feel unwell or have been having episodes of hypoglycaemia - low blood glucose)
If your blood glucose falls too low, you may have hypoglycaemia (see the box, left).
Oral hypoglycaemic agents
In some cases, you may be prescribed oral hypoglycaemic agents alongside or instead of insulin. These are medicines you swallow to lower the level of glucose in your blood. The two that can be used during pregnancy are:
- glibenclamide (from week 11 of the pregnancy)
Both metformin and glibenclamide can cause side effects, including:
- nausea (feeling sick)
- diarrhoea (passing loose, watery stools)
As with insulin, if you are using glibenclamide you may be at risk of hypoglycaemia (see box, left). This does not usually happen with metformin unless it is used in combination with insulin or glibenclamide.
For a full list of side effects, see the patient information leaflet that comes with your medicine.
Monitoring your unborn baby
If you have gestational diabetes, your unborn baby may be at risk of complications, such as being large for the state of pregnancy. Because of this, you may be offered extra antenatal appointments so your baby can be closely monitored during your pregnancy.
Appointments you may be offered include:
- an ultrasound scan around weeks 18-20 of your pregnancy to check your unborn baby's heart for any signs of abnormalities (if your gestational diabetes is diagnosed late into your pregnancy you may not be offered this scan)
- an ultrasound scan at weeks 28, 32, 36 and regular checks from week 38 of the pregnancy to monitor your baby's growth and the amount of amniotic fluid (the fluid that surrounds them in the womb)
If you have gestational diabetes and your baby is growing at a normal rate, you may be offered the chance to start labour (the process of giving birth) after week 38 of pregnancy.
This can be done by inducing labour. This is when labour is started artificially by inserting a pessary (tablet) or gel into your vagina, and a hormone drip in your arm (read about inducing labour for more information).
You can wait for labour to start naturally as long as your blood sugars are within normal levels, the ultrasound scans of the baby are normal, and there is no other problem in pregnancy.
If your baby is large for its gestational age (macrosomic), then your doctor or midwife should discuss the birth options with you.
Normal delivery is usually still possible but will depend on the size of the baby.
You should give birth at a hospital where healthcare professionals trained in resuscitating newborn babies are available 24 hours a day.
During labour and the birth, your blood glucose will be measured every hour and kept between 4 to 7 mmol/l. If you have been on insulin during pregnancy, you will be recommended to have an intravenous drip of insulin as well as glucose during labour, to allow careful control of your blood sugar levels.
Around two to four hours after the birth, your newborn baby's blood glucose will also be measured, this will usually be before the baby's second feed.