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Gestational diabetes

Published: September 2021

Please note that this information will be reviewed every 3 years after publication.

To access this leaflet in additional languages, please visit our Translations page.

This information is for you if you wish to know more about diabetes that develops in pregnancy or if you have been offered testing for gestational diabetes.

It may also be helpful if you are a partner, relative or friend of someone who is in this situation.

The information here aims to help you better understand your health and your options for treatment and care. Your healthcare team is there to support you in making decisions that are right for you. They can help by discussing your situation with you and answering your questions.

This information covers:

  • What gestational diabetes is
  • How it is diagnosed
  • What extra antenatal care you can expect
  • What this diagnosis means for you and your baby, now and in the future

Within this information, we may use the terms ‘woman’ and ‘women’. However, it is not only people who identify as women who may want to access this information. Your care should be personalised, inclusive and sensitive to your needs, whatever your gender identity.

A glossary of medical terms is available at A-Z of medical terms.

Key points

  • Gestational diabetes is diabetes that develops in pregnancy. Most women who have gestational diabetes have healthy pregnancies and healthy babies.
  • You will be given advice about blood glucose monitoring, diet, exercise and weight management to help treat the condition. You may be offered tablets or insulin injections. You will have further support in your pregnancy by a specialist healthcare team.
  • Occasionally gestational diabetes can lead to complications in pregnancy or during birth, especially if it goes unrecognised or is not well controlled.
  • Gestational diabetes usually goes away after the baby is born but you have a higher chance of developing gestational diabetes in a future pregnancy and type 2 diabetes in later life.

Diabetes that develops during pregnancy is known as gestational diabetes. It happens because your body cannot produce enough insulin (a hormone that helps to control blood glucose) to meet the extra needs of pregnancy. This results in high blood sugar levels (blood glucose).

Gestational diabetes usually starts in the middle or towards the end of pregnancy.

Gestational diabetes is common. It affects at least 4-5 in 100 women during pregnancy.

You are more likely to develop gestational diabetes if you have any of the following risk factors:

      • your body mass index (BMI) is 30 or higher
      • you have previously given birth to a baby weighing 4.5 kg (10 lbs) or more
      • you have had gestational diabetes before
      • you have a parent, brother or sister with diabetes
      • your family origin is South Asian, Chinese, African-Caribbean or Middle Eastern.

If you have any of the above risk factors, you should be offered a glucose test during your pregnancy. This may be a simple blood test in early pregnancy and/or a glucose tolerance test (GTT) when you are between 24 and 28 weeks pregnant.

A GTT involves fasting overnight (not eating or drinking anything apart from water):

      • In the morning, before breakfast, you will have a blood test. You are then given a glucose drink.
      • The blood test is repeated 1–2 hours later to see how you body reacts to the glucose drink.

If you have had gestational diabetes in a previous pregnancy, you will be offered either a kit to check your own blood glucose levels or a GTT in early pregnancy. If these are normal, you will be offered a GTT again at 24–28 weeks.

During your routine pregnancy care, your urine is tested for glucose. If glucose is present in your urine, then your healthcare team may recommend that you have a GTT.

Most women who develop gestational diabetes have healthy pregnancies and healthy babies but occasionally gestational diabetes can cause serious problems, especially if it is not recognised or treated.

If your blood glucose levels are high, the chances of you having an induced labour or a caesarean birth are increased.

The risks to your baby are:

  • being bigger than average
  • shoulder dystocia (where your baby’s shoulder gets stuck during birth)
  • stillbirth or the baby dying at or around the time of birth. This is uncommon.
  • needing additional care once they have been born, possibly in a neonatal unit
  • being at greater risk of developing obesity and developing type 2 diabetes in later life.

Controlling your levels of blood glucose during pregnancy and labour reduces the chances of these complications for you and your baby.

If you are diagnosed with gestational diabetes, you will be under the care of a specialist healthcare team and will be advised to have your baby in a hospital with a consultant-led maternity unit and a neonatal unit.

Your healthcare team may include a doctor specialising in diabetes, an obstetrician, a specialist diabetes nurse, a specialist diabetes midwife, a dietitian and your community midwife. You should start receiving extra antenatal care as soon as your gestational diabetes is diagnosed. Having gestational diabetes will mean more contact with your healthcare team.

Healthy eating and exercise

The most important treatment for gestational diabetes is a healthy eating plan and exercising regularly. Walking for 30 minutes after a meal can help with controlling your blood glucose levels. Gestational diabetes usually improves with these changes. You should have an opportunity to talk to a healthcare professional about choosing foods that will help to keep your blood glucose at a healthy and stable level. For more information about what to eat when you have gestational diabetes.

Monitoring your blood glucose

After you have been diagnosed with gestational diabetes, you will be shown how to check your blood glucose levels and told what your ideal level should be. If it does not reach this level with healthy eating and exercise, or if an ultrasound scan shows that your baby is larger than expected, you may need to take tablets or give yourself insulin injections. If your glucose level is very high at the time of diagnosis, then you may be offered treatment straight away, in addition to making changes to your diet and exercise.

Monitoring your baby

You should be offered extra ultrasound scans to monitor your baby’s growth more closely.

Advice and information

During your pregnancy, your healthcare professionals will give you information and advice about:

      • planning birth, including timing and types of birth, pain relief and changes to your medications during labour and after your baby is born
      • looking after your baby following birth
      • care for you after your baby is born including contraception.
Some women with gestational diabetes will need to take tablets and/or have insulin injections to control their blood glucose during pregnancy. Your healthcare team will advise you what treatment is best for you and your baby.
If you do need insulin, your specialist healthcare team will explain exactly what you need to do. This will include showing you how to inject yourself with insulin, how often to do it and when you should check your blood glucose levels.
You will have discussions about your options for birth with your healthcare professionals throughout your pregnancy.Your options include waiting for labour to start, having an induction of labour or having a planned caesarean birth. This will depend on your individual circumstances and preferences and your healthcare professional will discuss the risks and benefits of each option with you.
You will be advised to have your baby before 41 weeks of pregnancy and if there are pregnancy complications affecting either you or your baby, your healthcare team may recommend birth earlier than this.

It is important that your blood glucose level is controlled during labour and birth and it should be monitored to ensure it is not too high. You may be advised to have an insulin drip to help control your blood glucose level

  • Your baby will stay with you unless they need extra care. You can usually have skin-to-skin contact with your baby straight away if you choose this. Ocassionally they may need to be looked after in the neonatal unit if they are unwell or need extra support.
  • Your baby should have their blood glucose level tested a few hours after birth to make sure that it is not too low. 
  • Gestational diabetes usually goes away after birth and therefore you will be advised to stop taking all diabetes medications immediately after your baby is born. Before you go home, your blood glucose level will be tested to make sure that it has returned to normal.
  • You should be offered a fasting blood glucose test 6 - 13 weeks after the birth of your baby. A small number of women continue to have high blood glucose levels and will be offered further tests for diabetes. 
  • You should be offered information about your lifestyle, including diet, exercise and watching your weight, to reduce your chance of type 2 diabetes in the future.
  • Up to 50% of women who have had gestational diabetes develop type 2 diabetes within the following 5 years. You will therefore be advsied to have a test for this every year.
  • Breastfeeding is safe if you have gestational diabetes and your healthcare team will support you in feeding your baby.
  • Whichever way you choose to feed your baby, you should start feeding as soon as possible after birth, and then every 2–3 hours to help your baby’s blood glucose stay at a safe level. Babies born to mothers with gestational diabetes have a high risk of low sugar levels after birth, so you may be advised to hand express and give your baby this early breast milk (also called colostrum) in addition to breastfeeding directly.Your healthcare team will advise you how to do this.
  • It is safe to express colostrum in pregnancy, from 36 weeks onwards and to store it for use after giving birth.This can be helpful to supplement breastfeeding and expressing if you experience difficulties in breastfeeding after giving birth.Your healthcare team will bemable to advise you about how to store breastmilk safely.
  • You should inform a member of your healthcare team if you have any concerns about your baby’s wellbeing.

Having a healthy weight, eating a balanced diet and taking regular physical exercise before you become pregnant can reduce your risk of developing gestational diabetes again.

As soon as you find out you’re pregnant, contact your healthcare team for advice about your antenatal care as there is a chance you may develop gestational diabetes again (more than 1 in 3 women will get gestational diabetes again).

Emotional support

Having tests or treatment can be a stressful time. If you are feeling anxious or worried in any way, please speak to your healthcare team who can answer your questions and help you get support.

The support may come from healthcare professionals, voluntary organisations or other services.

Further information and resources are available on the NHS website.

Shared Decision Making

If you are asked to make a choice, you may have lots of questions that you want to ask. You may also want to talk over your options with your family or friends. It can help to write a list of the questions you want answered and take it to your appointment.

Ask 3 Questions

To begin with, try to make sure you get the answers to 3 key questions, if you are asked to make a choice about your healthcare:

  1. What are my options?
  2. What are the pros and cons of each option for me?
  3. How do I get support to help me make a decision that is right for me?

*Ask 3 Questions is based on Shepherd et al. Three questions that patients can ask to improve the quality of information physicians give about treatment options: A cross-over trial. Patient Education and Counselling, 2011;84:379-85 

Sources and acknowledgements
This information has been developed by the RCOG Patient Information Committee in collaboration with Diabetes UK. It is based on the NICE clinical guideline Diabetes in Pregnancy: 
management from preconception to the postnatal period (December 2020). The guideline contains a full list of the sources of 
evidence used.

Before publication this information was reviewed by the public and by representatives from the RCOG Women’s Network and the RCOG Women’s Voices Involvement Panel.

This page was last reviewed 14 September 2021.