Gestational diabetes – your questions answered

It happens when your body cannot produce enough insulin (which is a hormone that helps control blood sugar levels) to meet your body’s extra needs in pregnancy. 

Anyone can develop gestational diabetes during pregnancy, but you’re at an increased risk if: 

• you are over the age of 40 
• your body mass index (BMI) is above 30 – you can use the BMI healthy weight calculator to work out your BMI 
• you’ve previously had a baby weighing 4.5kg (10lb) or more at birth 
• you’ve had gestational diabetes in a previous pregnancy 
• one of your parents or siblings has diabetes 
• you are of South Asian, Black, African-Caribbean or Middle Eastern origin (even if you were born in the UK) 
• you have had a gastric bypass or other weight-loss surgery 

If any of these apply to you, you should be offered screening for gestational diabetes during your pregnancy. The screening test is called an oral glucose tolerance test (OGTT), which takes about 2 hours – you can read more about the test on the diabetes UK website.

Speak to your midwifery team if any of these apply and you haven’t been offered a screening. 

Gestational diabetes does not usually cause any symptoms. Most cases are discovered when your blood sugar levels are tested during screening for gestational diabetes. 

Some people may develop symptoms if their blood sugar levels gets too high (known as hyperglycaemia), such as: 

• increased thirst 
• needing to pass urine more often than usual 
• a dry mouth 
• tiredness 
• blurred eyesight 
• genital itching or thrush 

But some of these symptoms are common during pregnancy and are not necessarily a sign of gestational diabetes.  

Speak to your midwifery team or doctor if you’re worried about any symptoms you’re experiencing. 

Most people with gestational diabetes have healthy pregnancies with healthy babies. 

But 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 an assisted birth such as a caesarean
• polyhydramnios – where there’s too much fluid surrounding 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 birth, 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. 

Gestational diabetes is managed by controlling your blood sugar levels. You may 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 being more active. Gentle activities such as walking, swimming and prenatal yoga can help reduce blood sugar. You should tell your midwife or doctor before starting an activity you haven’t done before, and avoid contact sports or activities with a risk of injury.  

Read more about keeping active in pregnancy here.

If lifestyle changes don’t lower your blood sugar levels enough, you may need to take medication as well – these could be either 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 on the NHS website. 

Gestational diabetes normally dissappears after birth, but people 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. If your results are normal, you’ll be offered tests every year. 

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

Don’t wait until your next test if you start experiencing symptoms of diabetes. See your GP if you develop symptoms of high blood sugar, such as: 

• increased thirst 
• needing to pass urine more frequently 
• dry mouth 

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 a parent who had gestational diabetes may be more likely to develop diabetes or become obese later in life. 

If you’ve had gestational diabetes before and you’re planning a pregnancy, make sure you get checked for diabetes. Your GP can arrange this. 

If you have an unplanned pregnancy, talk to your GP as soon as possible and tell them you had gestational diabetes in your previous pregnancy. 

This is because diabetes can cause complications in pregnancy if it’s not well controlled. You can read more about diabetes and planning for pregnancy here.

If tests show you do not have diabetes, you’ll be offered screening earlier in pregnancy (soon after your first midwife appointment) and another test at 24 to 28 weeks if the first test is normal.