Diabetes, gestational

Overview

Gestational diabetes is high blood sugar (glucose) that develops during pregnancy and usually disappears after giving birth.

It can occur at any stage of pregnancy, but is more common in the second or third tremester.

It happens when your body cannot produce enough insulin – a hormone that helps control blood sugar levels – to meet your extra needs in pregnancy.

Gestational diabetes can cause problems for you and your baby during pregnancy and after birth. But the risks can be reduced if the condition is detected early and well managed.

Who's at risk of gestational diabetes

Any woman can develop gestational diabetes during pregnancy, but you're at an increased risk if:

your body mass index (BMI) is above 30 – use the healthy weight calculator to work out your BMI
you previously had a baby who weighed 4.5kg (10lbs) or more at birth
you had gestational diabetes in a previous pregnancy
1 of your parents or siblings has diabetes
your are of south Asian, Chinese, African-Caribbean or Middle Eastern origin (even if you were born in the UK)

If any of these apply to you, you should be offered screening for gestational diabetes during your pregnancy.

Symptoms of gestational diabetes

Gestational diabetes does not usually cause any symptoms.

Most cases are only discovered when your blood sugar levels are tested during screening for gestational diabetes.

Some women may develop symptoms if their blood sugar level gets too high (hyperglycaemia), such as:

increased thirst
needing to pee more often than usual
a dry mouth
tiredness

But some of these symptoms are common during pregnancy and are not necessarily a sign of gestational diabetes. Speak to your midwife or doctor if you're worried about any symptoms you're experiencing.

How gestational diabetes can affect your pregnancy

Most women with gestational diabetes have otherwise normal pregnancies with healthy babies.

However, gestational diabetes can cause problems such as:

your baby growing larger than usual – this may lead to difficulties during the delivery and increases the likelihood of needing induced labour or a caesarean section
polyhydramnios – too much amniotic fluid (the fluid that surrounds the baby) in the womb, which can cause premature labour or problems at delivery
premature birth – giving birth before the 37th week of pregnancy
pre-eclampsia – a condition that causes high blood pressure during pregnancy and can lead to pregnancy complications if not treated
your baby developing low blood sugar or yellowing of the skin and eyes (jaundice) after he or she is born, which may require treatment in hospital
the loss of your baby (stillbirth) – though this is rare

Having gestational diabetes also means you're at an increased risk of developing type 2 diabetes in the future.

Screening for gestational diabetes

During your first antenatal appointment (also called a booking appointment) at around weeks 8 to 12 of your pregnancy, your midwife or doctor will ask you some questions to determine whether you're at an increased risk of gestational diabetes.

If you have 1 or more risk factors for gestational diabetes you should be offered a screening test.

The screening test used is called an oral glucose tolerance test (OGTT), which takes about 2 hours.

It involves having a blood test in the morning, when you have not had any food or drink for 8 to 10 hours (though you can usually drink water, but check with the hospital if you're unsure). You're then given a glucose drink.

After resting for 2 hours, another blood sample is taken to see how your body is dealing with the glucose.

The OGTT is done when you're between 24 and 28 weeks pregnant. If you've had gestational diabetes before, you'll be offered an OGTT earlier in pregnancy soon after your booking, then another OGTT at 24 to 28 weeks if the first test is normal.

Treatments for gestational diabetes

If you have gestational diabetes, the chances of having problems with your pregnancy can be reduced by controlling your blood sugar levels.

You'll be given a blood sugar testing kit so you can monitor the effects of treatment.

Blood sugar levels may be reduced by changing your diet and exercise routine. However, if these changes don't lower your blood sugar enough, you will need to take medicine as well. This may be tablets or insulin injections.

You'll also be more closely monitored during your pregnancy and birth to check for any potential problems.

If you have gestational diabetes, it's best to give birth before 41 weeks. Induction of labour or a caesarean section may be recommended if labour does not start naturally by this time.

Earlier delivery may be recommended if there are concerns about your or your baby's health or if your blood sugar levels have not been well controlled.

Find out more about how gestational diabetes is treated.

Long-term effects of gestational diabetes

Gestational diabetes normally goes away after birth. But women who've had it are more likely to develop:

gestational diabetes again in future pregnancies
type 2 diabetes – a lifelong type of diabetes

You should have a blood test to check for diabetes 6 to 13 weeks after giving birth, and every year thereafter if the result is normal.

See your GP if you develop symptoms of high blood sugar, such as increased thirst, needing to pee more often than usual, and a dry mouth – do not wait until your next test.

You should have the tests even if you feel well, as many people with diabetes do not have any symptoms.

You'll also be advised about things you can do to reduce your risk of getting diabetes, such as maintaining a healthy weight, eating a balanced diet and exercising regularly.

Some research has suggested that babies of mothers who had gestational diabetes may be more likely to develop diabetes or become obese later in life.

Planning future pregnancies

If you've had gestational diabetes before and you're planning to get pregnant, make sure you get checked for diabetes. Your GP can arrange this.

If you do have diabetes, you should be referred to a diabetes pre-conception clinic for support to ensure your condition is well controlled before you get pregnant.

Treatment

If you have gestational diabetes, the chances of having problems with the pregnancy can be reduced by controlling your blood sugar (glucose) levels.

You'll also need to be more closely monitored during pregnancy and labour to check if treatment is working and to check for any problems.

Checking your blood sugar level

You'll be given a testing kit that you can use to check your blood sugar level.

This involves using a finger-pricking device and putting a drop of blood on a testing strip.

You'll be advised:

how to test your blood sugar level correctly
when and how often to test your blood sugar – most women with gestational diabetes are advised to test before breakfast and one hour after each meal
what level you should be aiming for – this will be a measurement given in millimoles of glucose per litre of blood (mmol/l)

Diabetes UK has more information about monitoring your glucose levels.

A healthy diet

Making changes to your diet can help control your blood sugar levels.

You should be referred to a dietitian, who can give you advice about your diet and how to plan healthy meals.

You may be advised to:

eat regularly – usually 3 meals a day – and avoid skipping meals
eat starchy and low glycaemic index (GI) foods that release sugar slowly – such as wholewheat pasta, brown rice, granary bread, all-bran cereals, pulses, beans, lentils, muesli and plain porridge
eat plenty of fruit and vegetables – aim for at least 5 portions a day
avoid sugary foods – you do not need a completely sugar-free diet, but swap snacks such as cakes and biscuits for healthier alternatives such as fruit, nuts and seeds
avoid sugary drinks – sugar-free or diet drinks are better than sugary versions. Fruit juices and smoothies can also be high in sugar, and so can some "no added sugar" drinks, so check the nutrition label or ask your health care team
eat lean sources of protein in your diet, such as fish

It's also important to be aware of foods to avoid during pregnancy, such as certain types of fish and cheese.

Diabetes UK has more information about diet and lifestyle with gestational diabetes.

Exercise

Physical activity lowers your blood glucose level, so regular exercise can be an effective way to manage gestational diabetes.

You'll be advised about safe ways to exercise during pregnancy. Find out more about exercise in pregnancy.

A common recommendation is to aim for at least 150 minutes (2 hours and 30 minutes) of moderate intensity activity a week, plus strength exercises on 2 more days a week.

Medicine

You may be given medicine if your blood sugar levels are still not well controlled 1 to 2 weeks after changing your diet and exercising regularly, or if your blood sugar level is very high. This may be tablets – usually metformin – or insulin injections.

Your blood sugar levels can increase as your pregnancy progresses, so even if they are well controlled at first, you may need to take medicine later in pregnancy.

You can usually stop taking these medicines after you give birth.

Tablets

Metformin is taken as a tablet up to 3 times a day, usually with or after meals.

Side effects of metformin can include:

feeling sick
being sick
stomach cramps
diarrhoea
loss of appetite

Occasionally a different tablet called glibenclamide may be used.

Insulin injections

Insulin may be recommended if:

you can't take metformin or it causes side effects
your blood sugar level isn't controlled with metformin
you have very high blood sugar
your baby is very large or you have too much fluid in your womb (polyhydramnios)

Insulin is taken as an injection, which you'll be shown how to do yourself. Depending on the type of insulin you're prescribed, you may need to inject yourself before meals, at bedtime, or on waking.

You will be told how much insulin to take. Blood sugar levels usually increase as pregnancy progresses, so your insulin dose may need to be increased over time.

Insulin can cause your blood sugar to fall too low (hypoglycaemia). Symptoms of low blood sugar include feeling shaky, sweaty, hungry, turning pale, or finding it difficult to concentrate.

If this happens, you should test your blood sugar – treat it straight away if it's low. Find out how to treat low blood sugar.

You'll be given information about hypoglycaemia if you're prescribed insulin.

Monitoring your pregnancy

Gestational diabetes can increase the risk of your baby developing problems, such as growing larger than usual.

Because of this, you'll be offered extra antenatal appointments so your baby can be monitored.

Appointments you should be offered include:

an ultrasound scan at around weeks 18 to 20 of your pregnancy to check your baby for abnormalities
ultrasound scans at weeks 28, 32 and 36 – to monitor your baby's growth and the amount of amniotic fluid, plus regular checks from week 38 onwards

Giving birth

The ideal time to give birth if you have gestational diabetes is usually around weeks 38 to 40.

If your blood sugar is within normal levels and there are no concerns about your or your baby's health, you may be able to wait for labour to start naturally.

But you'll usually be offered induction of labour or a caesarean section if you have not given birth by 40 weeks and 6 days.

Earlier delivery may be recommended if there are concerns about your or your baby's health, or if your blood sugar levels have not been well controlled.

You should give birth at a hospital where specially trained health care professionals are available to provide appropriate care for your baby.

When you go into hospital to give birth, take your blood sugar testing kit with you, plus any medicines you're taking.

Usually you should keep testing your blood sugar and taking your medicines until you're in established labour or you're told to stop eating before a caesarean section.

During labour and delivery, your blood sugar will be monitored and kept under control. You may need to have insulin given to you through a drip, to control your blood sugar levels.

After birth

You can usually see, hold and feed your baby soon after you've given birth. It's important to feed your baby as soon as possible after birth (within 30 minutes) and then at frequent intervals (every 2 to 3 hours) until your baby's blood sugars are stable.

Your baby's blood sugar level will be tested starting 2 to 4 hours after birth. If it's low, your baby may need to be temporarily fed through a tube or a drip.

If your baby is unwell or needs close monitoring, they may be looked after in a specialist neonatal unit.

Any medicines you were taking to control your blood sugar will usually be stopped after you give birth. You'll usually be advised to keep checking your blood sugar for 1 or 2 days after you give birth.

If you're both well, you and your baby will normally be able to go home after 24 hours.

You should have a blood test to check for diabetes 6 to 13 weeks after giving birth. This is because a small number of women with gestational diabetes continue to have raised blood sugar after pregnancy.

If the result is normal, you'll usually be advised to have an annual test for diabetes. This is because you're at an increased risk of developing type 2 diabetes – a lifelong type of diabetes – if you've had gestational diabetes.

The information on this page has been adapted by NHS Wales from original content supplied by

NHS website nhs.uk