Glucose tolerance test in pregnancy

Glucose tolerance test in pregnancy

Maternity Department
Patient Information Leaflet

What is a glucose tolerance test (GTT)?

It is a test which is carried out during pregnancy to find out if you have gestational diabetes.

A diagnosis of gestational diabetes will lead to increased monitoring and may lead to increased interventions during your pregnancy and/or labour.

What is gestational diabetes?

It is usually a temporary form of diabetes where you have high blood glucose levels, especially after eating, and it affects women during pregnancy.

Normally, the amount of glucose in the blood is controlled by a hormone called insulin. However, during pregnancy, some women develop higher than normal levels of glucose in their blood which their insulin cannot bring under control.

Gestational diabetes usually develops in the third trimester (after 28 weeks) and normally goes away after the baby is born. However, women who develop gestational diabetes are more likely to develop type 2 diabetes later in life.

It is important that we find out if you have gestational diabetes as you will need to have more antenatal appointments to monitor you and your baby. This is because if you have it, you are more likely to have complications during pregnancy and birth, particularly if the diabetes is not treated.

Who gets gestational diabetes?

You are at a higher risk of developing gestational diabetes if:

• You have had gestational diabetes during previous pregnancies.

• You have a close relative (parent, brother, sister, child) with diabetes.

• You have had a large baby in a previous pregnancy.

• You have had an unexplained stillborn baby in a previous pregnancy.

• You have a body mass index (BMI) over 30.

• You have had sugar (glucose) in your urine during your pregnancy.
• You have polycystic ovary syndrome.
• You are taking certain antipsychotic medications.

• Your family origins are South Asian (specifically India, Pakistan or Bangladesh), Black (specifically Caribbean or African) or Middle Eastern (specifically Saudi Arabia, United Arab Emirates, Iraq, Jordan, Syria, Oman, Qatar, Kuwait, Lebanon or Egypt).

What are the symptoms?

Often there are no symptoms with gestational diabetes. For this reason, if you are at increased risk of gestational diabetes, you will be offered a GTT test which is carried out in weeks 25 to 27 of pregnancy. However, if you have had gestational diabetes in a previous pregnancy, the test will be carried out at 16 to 18 weeks of pregnancy.

High blood glucose can cause some symptoms, including

• a dry mouth with increased thirst;
• needing to urinate frequently, especially at night;
• tiredness;
• recurrent infections, such as thrush (a yeast infection) or
• blurred vision.

What does the test involve?

• The night before the test, you must not eat anything from 10pm. You can have sips of water. Please note you can still take any regular medication as usual with water (not squash or juice). If the medication needs to be taken with food, delay this dose until after the test. If you have concerns regarding your medication, please contact the diabetes centre.

• When you arrive at the clinic, we will take a sample of your blood.
• Then, you will need to drink a glucose drink within five to six minutes.
• After this, you will need to sit in the department for two hours. During this time you will not be able to eat, drink or smoke. It is a good idea to bring a magazine, book or something to do, and also a snack for after the test.
• After two hours, we will take a second blood test. The test is then finished and you can go home.

How do I book the test?

Your community midwife or the antenatal clinic staff will advise you on how to book your test.

Where does the test take place?

It will be at:

• The Briar Suite, Brierley Hill Health and Social Care Centre, Venture Way, Brierley Hill, DY5 1RU (opposite Asda car park).

Please make sure you know where your test is taking place.

How do I get the results?

The results of your test will be reviewed within two working days. If the result is normal, there is no further action required and your community midwife will be notified of the result. She will tell you the results.

If the result is abnormal, we will refer you to a joint antenatal/diabetic clinic and they will arrange to see you.

How is gestational diabetes treated?

If you have gestational diabetes, when you are referred to the antenatal/diabetes clinic you will be given information about monitoring and controlling your blood glucose (sugar) levels.

Sometimes, changing diet and exercising more will be enough to control your gestational diabetes. Some women may need medication.

You will be offered more frequent antenatal appointments so that you and your unborn baby can be closely monitored.

If you need to rearrange your test, please call 01384 244312.

If you have any questions, or if there is anything you do not understand about this leaflet, please contact:

Your community midwife on 01384 244358 (9am to 5pm, Monday to Friday)

Pregnancy Day Assessment Unit on 01384 244312 (8am to 6.30pm, Monday to Friday)

Diabetes centre on 01384 456111 ext. 3399

If you have any feedback on this patient information leaflet, please email dgft.patient.information@nhs.net.