Glucose Tolerance Test (GTT) in Pregnancy

What is a Glucose Tolerance Test (GTT)?

You have been asked to have a GTT as you have certain risk factors that may increase your chance of developing Gestational Diabetes (diabetes in pregnancy).

Gestational Diabetes is a condition caused by your body not being able to produce enough Insulin (a hormone produced by your pancreas which helps regulate blood sugar) to meet the extra needs of pregnancy. It develops during pregnancy, and typically resolves after childbirth, but it requires careful management to ensure the health of both mother and baby. Poorly controlled Gestational Diabetes can lead to complications in pregnancy.

The maternal complications are:

• Pre-eclampsia.
• Increased risk of recommended labour induction.
• Increased risk of caesarean section.
• Birth complications – such as shoulder dystocia (where the baby’s shoulders get stuck during delivery), excess fluid around the baby in utero (polyhydramnios).
• Higher likelihood of mum developing Type 2 diabetes in the future.

The neonatal complications are:

• Neonatal hypoglycaemia (low blood sugars after birth)
• Jaundice.
• Breathing difficulties.
• Future risk of developing obesity and Type 2 diabetes.

A GTT is a test to see if your body is able to process glucose (sugar) properly. This is typically done between weeks 24 to 31⁺⁶ of your pregnancy.

What do I need to do for the test?

The test will be completed in the antenatal clinic. It is important that you do not eat or drink anything other than plain tap water from 10:00pm the night before the test. If you do eat or drink after this time, the test cannot go ahead. Vaping and smoking cigarettes must be avoided. Having mints, chewing gum, sugar-coated medication and antacids such as Gaviscon will also result in the test being abandoned. Other regular medications (such as tablets to control blood pressure) should still be taken – please seek advice if you need help regarding this.  

What happens during the test?

• When you arrive for your appointment, the healthcare professional will go through some basic information and answer any questions you may have.
• A sample of blood will be taken.
• You will then be given a glucose drink (usually orange flavoured); it is important to drink all of this within 10 minutes.
• You will then be asked to wait in the waiting area for 2 hours. During this time, you may use the toilet, but should not vape, smoke cigarettes, eat or drink. You should remain in the waiting area for the duration of this test.
• After 2 hours, a further sample of blood will be taken.
• Once this sample has been taken the test is complete; you are then able to leave and eat and drink normally.

How will I get the result?

If the results show you have gestational diabetes, you will be contacted by the Diabetes Specialist Midwife and informed that you have gestational diabetes.

You will then be asked to attend a small group information session where you will be provided with blood glucose monitoring equipment to enable you to test your blood glucose (sugar levels) before breakfast and after meals for the rest of your pregnancy. You will also be given an appointment for the Specialist Diabetes Clinic alongside additional scans to monitor your baby’s growth.

Contact numbers

If you need further advice, or you need to rearrange this appointment, please contact the appropriate number below:

University Hospital North Tees

Telephone: 01642 624212

Monday to Friday, 8:00am to 4:30pm

University Hospital Hartlepool

Telephone: telephone:01429522865

Monday to Friday, 8:00am to 4:30pm

If you have any worries or concerns, you should contact your Community Midwife or the advice line for the Hospital you intend to have your baby.

Patient Experience Team (PET)

North Tees and Hartlepool NHS Foundation Trust would like your feedback. If you would like to share your experience about your care and treatment or on behalf of a patient, please contact The Patient Experience Team who will help you to do this.

This service is based at the University Hospital of North Tees but also covers The University Hospital of Hartlepool, our community hospitals and community health services.

North Tees and Hartlepool NHS Foundation Trust
Telephone: 01642 624719
Freephone: 0800 092 0084
Email: [email protected]
Monday to Friday, 9:30 am to 4:00 pm

Out of Hours
If you wish to speak to a senior member of Trust staff, please contact the hospital switchboard (numbers below).