Gestational diabetes

Being told you have gestational diabetes can bring up plenty of questions, especially if you have been feeling well and the diagnosis came from a routine test. Gestational diabetes is high blood sugar that develops during pregnancy. It usually goes away after birth, although it does mean you have a higher chance of developing type 2 diabetes later in life.

It happens when your body cannot produce enough insulin to meet the extra needs of pregnancy. With appropriate monitoring and care, most people with gestational diabetes have healthy pregnancies and healthy babies.

What is gestational diabetes?

Insulin is a hormone that helps control the amount of glucose, or sugar, in your blood. During pregnancy, the body needs to produce more insulin. Gestational diabetes develops when it cannot make enough to meet those additional needs, causing blood glucose levels to rise.

According to the NHS, gestational diabetes can develop at any stage of pregnancy but is more common during the second or third trimester.

It is different from having type 1 or type 2 diabetes before becoming pregnant. If you already had diabetes before pregnancy, your care will follow a different pathway.

What are the symptoms of gestational diabetes?

Gestational diabetes does not usually cause symptoms. Many people only discover they have it after having a blood glucose test during pregnancy.

When blood glucose becomes high, the NHS says possible symptoms can include:

feeling more thirsty than usual
needing to urinate more often
a dry mouth
tiredness
blurred vision
genital itching or thrush

Several of these can also happen during pregnancy for other reasons, so experiencing one does not mean you have gestational diabetes.

Speak to your midwife or GP if you are concerned about symptoms rather than trying to work out the cause yourself.

Who is offered testing for gestational diabetes?

In the UK, testing is generally offered based on risk factors rather than routinely to every pregnant person.

NICE recommends assessing the risk of gestational diabetes at the booking appointment. Factors that may mean you are offered testing include:

a body mass index of 30 kg/m² or above
previously having a baby weighing 4.5 kg or more
having gestational diabetes in a previous pregnancy
having a parent or sibling with diabetes
having a family background with a higher prevalence of diabetes

Your midwife will discuss your individual risk factors and whether testing is recommended.

Having a risk factor does not mean you will develop gestational diabetes. Equally, gestational diabetes can occur in people who may not have expected to be at risk.

How is gestational diabetes diagnosed?

The main test used to diagnose gestational diabetes is an oral glucose tolerance test, often shortened to OGTT.

The test checks how your body manages glucose. NICE recommends an OGTT for people with certain risk factors, although when you are offered the test can depend on your medical and pregnancy history.

If you have had gestational diabetes in a previous pregnancy, you may be offered earlier testing or blood glucose monitoring as well as further testing later in pregnancy if the earlier result is normal.

Your maternity team should explain how to prepare for the test, what will happen and how you will receive your results.

What happens after a diagnosis?

If you are diagnosed with gestational diabetes, you should receive additional support from a healthcare team experienced in diabetes and pregnancy.

Care usually includes learning how to monitor your blood glucose. Your team will explain when to check it, what readings they want you to aim for and what to do if your results are outside the range they have given you.

You will also receive individual advice about food and physical activity. This is not about blaming you for the diagnosis. Gestational diabetes develops because the body cannot produce enough insulin for the extra demands of pregnancy, and many factors that affect someone’s risk cannot be changed.

Some people can manage their blood glucose through dietary changes and activity, while others need medication. RCOG states that tablets or insulin may be offered when needed.

Your healthcare team will decide what is appropriate for you. Do not start, stop or change medication without speaking to them.

Does gestational diabetes affect the baby?

Gestational diabetes can increase the chance of some pregnancy and birth complications, particularly if blood glucose levels are not well controlled.

RCOG explains that possible complications include the baby growing larger than average, shoulder dystocia during birth, the baby needing additional care after birth and an increased likelihood of induction or caesarean birth. Gestational diabetes is also associated with an increased risk of pre-eclampsia.

These are increased chances, not predictions of what will happen in an individual pregnancy. RCOG notes that most people with gestational diabetes have healthy pregnancies and healthy babies.

Managing blood glucose and attending the additional monitoring offered by your maternity team can reduce the chance of complications.

What extra pregnancy care might you have?

A diagnosis usually means more contact with your maternity and diabetes teams.

Your care may involve:

regular reviews of your blood glucose readings
support with food and physical activity
medication if clinically needed
additional ultrasound scans to monitor your baby’s growth
discussions about your birth and the timing of birth

The exact plan depends on your blood glucose levels, whether you need medication, your baby’s growth and other aspects of your health and pregnancy.

Your team should discuss your options with you rather than assuming that one approach is right for everyone with gestational diabetes.

Food and gestational diabetes

A diagnosis can make eating feel suddenly complicated, but there is no need to treat food as something you have failed at.

Your diabetes team or dietitian can give you personalised guidance on meals, carbohydrates and how different foods affect your blood glucose. RCOG recommends a healthy diet and regular physical activity as part of managing gestational diabetes.

Avoid making very restrictive dietary changes or cutting out major food groups without professional advice. Pregnancy still involves nutritional needs that should be considered alongside blood glucose management.

If you are struggling with nausea, food aversions, cultural or religious dietary requirements, allergies, financial constraints or a history of difficult feelings around food, tell your healthcare team. Advice can be adapted to your circumstances.

What happens after the baby is born?

Gestational diabetes usually goes away after birth, but follow-up still matters.

The NHS advises having a blood test after pregnancy to check whether blood glucose has returned to an expected level. If the result is normal, ongoing diabetes testing is usually recommended because having gestational diabetes increases your future risk of type 2 diabetes.

There is also a higher chance of gestational diabetes in a future pregnancy. If you become pregnant again, tell your maternity team that you have had it before so they can arrange the appropriate testing.

Your baby may also have their blood glucose checked after birth. Your maternity and neonatal teams can explain what monitoring is recommended for your baby and why.

When to get professional advice

Contact your midwife, diabetes team or GP if you have questions about your blood glucose readings, monitoring equipment, food, medication or any part of your gestational diabetes care. Do not wait for your next routine appointment if your care team has told you that particular blood glucose readings require earlier contact.

Gestational diabetes is associated with an increased risk of pre-eclampsia. Seek immediate maternity advice if you develop symptoms such as a severe headache, problems with your vision, pain below your ribs, vomiting or sudden swelling of your face, hands or feet.

Contact your maternity unit if you have its number. If you cannot reach your maternity service or are unsure where to seek help, contact NHS 111. Call 999 for a life-threatening emergency.

You should also contact your maternity team promptly if you are worried about your baby’s movements or have any other urgent concern about your pregnancy. You do not need to wait until you are certain something is wrong before asking for professional advice.