What are the risks of gestational diabetes?

Gestational diabetes can cause problems in pregnancy. But the risk of these problems can be reduced if you can manage your blood sugar well.

Having gestational diabetes can increase the risk of problems during your pregnancy and your baby’s birth. But a risk only means that something might happen, not that it will. 

Most people with gestational diabetes have healthy pregnancies and healthy babies, as long as their condition is diagnosed and their blood sugar (glucose) levels are managed. Your healthcare team will support you through your pregnancy, to help reduce the risks for you and your baby. 

This page goes into detail about the problems gestational diabetes can cause for your baby, and the possible impact on your pregnancy and labour. There might also be a longer-term impact of gestational diabetes, for you and your baby. 

"I suppose everybody who is pregnant has something – there’s always something that doesn’t go right – but I was really worried. You just want it to be perfect, don’t you?"

Problems in pregnancy

Gestational diabetes can cause problems if you cannot keep your blood sugar levels low. The risks vary from person to person, and many people have no issues at all. Your healthcare team can talk to you about your risk of problems, which can include:

Having a large baby 

If your blood sugar level is high, your body will produce more insulin. Sugars can pass through the placenta into your baby’s blood. Your baby could start to grow larger than usual and be heavier at birth (known as macrosomia). Babies weighing more than 4kg (8lb 8oz) at birth have macrosomia.

Having a large baby can cause problems when you give birth. One of the baby’s shoulders could get stuck in the birth canal (shoulder dystocia). This can increase your risk of tearing, and you will need help to release the baby’s shoulder. Your baby could even be at risk of nerve damage or broken bones because of it.

Your baby's weight will be monitored in pregnancy using ultrasound scans. If your baby is large, you may be advised to have an early induction (starting labour artificially) or planned caesarean section.

Read more about giving birth with gestational diabetes.

Too much amniotic fluid 

Having too much amniotic fluid (the liquid that surrounds the baby in the womb) is called polyhydramnios. It doesn’t often cause any problems. But it can lead to premature labour, or problems with the position of the baby or the umbilical cord.  

“I was diagnosed after polyhyrdramnios was picked up at a scan at 28 weeks. I had no risk factors, and I was absolutely gutted. I have a history of eating disorders so I was scared that following a strict diet would trigger unhelpful behaviours. Luckily, I was able to control things with diet and exercise. My little boy (my second child) was born after an induction (unrelated to my gestational diabetes) at 38 weeks, happy and healthy.”


Premature birth

Your baby may be born early if your healthcare team feels it’s better for you, rather than carrying on with the pregnancy. Some studies have also shown that some people with gestational diabetes go into premature labour.

Read more about premature labour and birth

'You find all these things out, and they are all incredibly rare, but I did really worry. That’s why I was so motivated to manage my glucose levels.' 



This is a condition that causes high blood pressure during pregnancy. It can lead to pregnancy complications if it is not treated.

Early signs of pre-eclampsia include having high blood pressure, and protein in your urine (wee). It's not likely you'll notice these signs, but they should be picked up during your routine antenatal appointments. Find out more about pre-eclampsia.

Low blood sugar in your baby

Blood sugar is vital for your baby’s brain and growth. But having gestational diabetes can cause babies to have low blood sugar (hypoglycaemia) at first.

Feed your baby as soon as you can after you give birth, and then at least every 2 to 3 hours after that. Read more about feeding your baby if you’ve had gestational diabetes

Your baby’s blood sugar levels will be checked soon after birth. If their blood sugar is low, you and your baby may need to stay at the hospital for at least 24 hours. Your healthcare team will check your baby’s sugar levels often, and provide extra care if needed, until their levels are normal. 

Speak to your healthcare team for advice on how to reduce your baby’s risk of low blood sugar levels after they are born.

Jaundice in your baby

Some babies develop yellowing of the skin and eyes (jaundice) after they are born. This can be more common if you have gestational diabetes. In most cases, your midwife or health visitor can help you to monitor jaundice at home. But some babies will need hospital treatment. 

Your midwife will let you know the signs to look out for in case your baby should be reviewed in hospital, and when it’s safe to stay at home.


Having gestational diabetes can cause babies to die before birth (stillbirth), or soon after birth. This is scary, but the risk is low. Getting a diagnosis and managing your gestational diabetes  with the help and support of your healthcare team reduces the risk, as well.

Longer-term health risks for you and your baby

Gestational diabetes can cause problems for you and your baby in the longer term. 

While gestational diabetes should go away once your baby is born, you will be at risk of it again in any future pregnancies. You will also be more likely to develop type 2 diabetes in the future. Your baby may be at greater risk of obesity or diabetes in their lifetime.

You can reduce your risk of health issues in the future by staying a healthy weight, eating a balanced diet and working out. These are also good ways for your child to stay healthy as they grow.

Find out more about the long-term effects of gestational diabetes.

Keeping the risks in perspective

It is natural to worry about these risks, but try not to worry too much. Every pregnancy carries some risks, and although you can’t remove them, there are ways that you can reduce them.

Talk to your midwife if you have any of the risk factors for gestational diabetes, but have not been tested.

If you have been diagnosed, the best thing you can do is follow your healthcare team’s advice on how to manage your condition. Make sure you go to all your extra antenatal care check-ups, too.

Remember, most people who develop diabetes in pregnancy have healthy pregnancies and healthy babies, as long as their condition is diagnosed and managed.

Your mental health

Talk to your midwife if you feel very worried or anxious about your gestational diabetes. They will be able to help you to get more information and support, if you need it. 

You can also speak to our midwives on the Tommy’s Midwives Helpline on 0800 014 7800 (Monday to Friday, 9am to 5pm), or email us at [email protected].

Find out more about your mental health before, during and after pregnancy.

Royal College of Obstetricians & Gynaecologists, Diabetes UK (2021). Gestational diabetes - Information for you. Available at: https://www.rcog.org.uk/media/b10mqyfw/pi-gestational-diabetes.pdf (Accessed January 2024) (Page last reviewed 09/2021)

Ye W, Luo C, et al. (2022). ‘Gestational diabetes mellitus and adverse pregnancy outcomes: systematic review and meta-analysis'. BMJ. :e067946. https://doi.org/10.1136/bmj-2021-067946

Rodrigo N, Glastras SJ (2020). ‘Pathophysiology Underpinning Gestational Diabetes Mellitus and the Role of Biomarkers for its Prediction’. EMJ. https://doi.org/10.33590/emj/19-00150

Royal College of Obstetricians & Gynaecologists (2012). Shoulder Dystocia. Green-top Guideline No. 42 (2nd Edition). Available at: https://www.rcog.org.uk/media/ewgpnmio/gtg_42.pdf (Accessed January 2024) (Page last reviewed 16/12/2020)

National Institute for Health and Care Excellence (2020). Diabetes in pregnancy: management from preconception to the postnatal period. NICE guideline 3. Available at: https://www.nice.org.uk/guidance/ng3 (Accessed January 2024) (Page last reviewed 16/12/2020)

NHS website (2020). Polyhydramnios (too much amniotic fluid). https://www.nhs.uk/conditions/polyhydramnios/ (Accessed January 2024) (Page last reviewed 08/12/2022. Next review due 08/12/2025)

Royal College of Obstetricians & Gynaecologists (2022). Pre-eclampsia: Information for you. Available at: https://www.rcog.org.uk/media/rnulgc5d/pi_pre-eclampsia-2022.pdf  (Accessed January 2024) (Page last reviewed 16/12/2020)

Nakshine VS, Jogdand SD (2023). ‘A Comprehensive Review of Gestational Diabetes Mellitus: Impacts on Maternal Health, Fetal Development, Childhood Outcomes, and Long-Term Treatment Strategies’. Cureus. 15(10):e47500. https://doi.org/10.7759/cureus.47500


Review dates
Reviewed: 15 February 2024
Next review: 15 February 2027