When do you take the diabetes test during pregnancy

About Oral Glucose Tolerance Test (OGTT) for pregnant women

Your doctor or midwife has requested a Glucose Tolerance Test from the laboratory, which is used to discover whether you have gestational diabetes. This webpage is intended to provide you with information about the examination.

Here you can find our information in Dutch about Oral Glucose Tolerance Test (OGTT) for pregnant women (Orale glucose tolerantietest (OGTT) bij zwangere vrouwen).

What is gestational diabetes?

If you have gestational diabetes, this means that there is too much glucose in your blood during your pregnancy. Glucose is a type of sugar. Having too much of it in your blood is not good for your baby. It can also lead to permanent diabetes for yourself.

The Oral Glucose Tolerance Test (OGTT) shows whether you have gestational diabetes. If this should be the case, you can do something about this by adapting your diet, which means eating certain foods and avoiding others. In some cases, you may also receive medication for gestational diabetes.

Making an appointment

The doctor’s assistant will book an appointment for the test at the laboratory. The laboratory is called the department Bloedafname in Dutch. Also you will get an appointment to discuss the results by telephone.

The examination starts either at 8.00 or at 10.30 am. At HMC Antoniushove, the laboratory for blood testing (Bloedafname) is on the ground floor: follow the orange walking route. At HMC Westeinde the laboratory (Bloedafname) is on the ground floor: follow the blue walking route. To find the laboratory (Bloedafname) at HMC Bronovo, follow walking route 86. Please report to the laboratory at least 5 minutes before the examination.

Purpose of the test

The test is intended to establish how well your body processes glucose. If your body cannot process glucose properly, too much of it will remain in your blood. In other words, this means that you have gestational diabetes.

During the examination, you will be asked to have a sweet drink. The amount of glucose in your blood before and after you drink this is measured.

Preparation

You must fast before the examination. This means that you may not eat, drink or smoke anything after 10.00 pm on the night before the examination. You may drink water and take any medication you need to. You may only have something else to eat or drink after the examination is finished the next morning.

How long will the examination take?

The examination takes over two hours to complete.

The examination

On the day of the examination, report to the blood testing department at the hospital where you have your appointment. Here you can hand in your application form at the reception desk. Please also show your patient ID card. After signing in, please go to the waiting room.
We will take a small blood sample by pricking your finger and your arm. After this, you will be given a sweet drink. You can choose which drink you prefer:

• 200 ml of a glucose drink (in which 75 ml of glucose has been dissolved)
• 200 ml of a lemon or orange-flavoured drink. We will serve this drink ice cold

Some women feel nauseous after drinking this.

Another blood sample will be taken two hours after you had the sweet drink. This time a blood sample will be taken from your arm.

You may not eat, drink or smoke during the examination. You should also not exert yourself. You may only drink water. We recommend that you bring a book or something else to occupy yourself with while you are waiting during the examination.

Glucose Day Curve Test

In case you have had weight loss surgery (e.g. gastric bypass) we recommend a different way of testing. The sugary drink might make you feel sick and weak. Instead of this drink we would do a test called The Glucose Day Curve. This test can also be done for other reasons than a previous surgery to the stomach.

Your blood will be drawn 3 times in one day:

• The first time on an empty stomach at 8.00 am. After this blood draw you can have your breakfast.
• The second time at 12.00 pm (lunchtime)
• The third time at 4.00 pm.

You don’t have to stay between these blood draws.

Waiting during the examination

At HMC Bronovo, the time between giving the two blood samples is spent in the waiting room at the poli Gynaecologie (gynaecology outpatient clinic), which is on the second floor (route 24). Please report back to the laboratory five minutes before the scheduled time for giving the second blood sample.
At HMC Antoniushove and HMC Westeinde, the time between giving the two blood samples is spent in a special waiting room at the blood testing department.

The results

An appointment will have been made with you to discuss the results by telephone. This usually is within two working days after the examination.

Cancelling the appointment

If you have any symptoms of a coronavirus infection or if you are ill on the day of the examination, please call us as soon as possible to make a new appointment. You can contact the Polikliniek Gynaecologie (gynaecology outpatient clinic) on telephone number 088 979 24 22.

If you are unable to attend the appointment for any other reason, please cancel your appointment at least 24 hours before the examination. You can reach us Monday through Friday during office hours on telephone number 088 979 24 22. This will allow us time to make an appointment with another patient instead. If you do not cancel your appointment on time, you will be charged the legally applicable no-show fee.

Any questions?

If you still have any questions about the examination after reading this leaflet, please contact the laboratory, which can be reached Monday through Friday from 8.00 am to 4.30 pm on telephone number 088 979 28 54.

The Department of Clinical Chemistry and Laboratory Medicine is ISO 15189 accredited under number M068.

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