Glucose tolerance test in pregnancy

Definition - What is a Glucose Tolerance Test?

The oral glucose tolerance test (oGTT) is a test that checks the body's processing of glucose. Elevated blood sugar levels in this test suggest a glucose tolerance disorder or even diabetes mellitus. The oral glucose tolerance test is carried out as part of prenatal care between the 24th and 28th week of pregnancy in order to rule out gestational diabetes.

Read more on the subject at: Glucose Tolerance Test - What Is It For?

Indications

The glucose tolerance test is carried out in all pregnant women between the 24th and 28th week of pregnancy as part of prenatal care. In the case of risk factors for gestational diabetes, such as If you have gestational diabetes in a previous pregnancy, your fasting blood sugar can be determined before the 24th week of pregnancy.

Read more on this topic at: Examinations during pregnancy

Preparation - do you have to be sober?

In the glucose tolerance test, two forms must be distinguished. The “normal” glucose tolerance test (75g-oGTT) and the glucose tolerance test during pregnancy (50g-oGTT) differ in the amount of sugar in the drinking solution.

When testing during pregnancy, the pregnant woman does not have to be sober. However, if this test shows increased values, the regular 75g-oGTT must be carried out again. For this test you should be sober in any case, i.e. have not eaten or consumed any sweet drinks 12 hours beforehand.

procedure

During the glucose tolerance test during pregnancy, the patient has to drink a sugar solution with 50g glucose. After waiting for an hour, the blood sugar level is measured. If this is below 135mg / dl, gestational diabetes can be excluded. If the value is above 135mg / dl, the blood sugar is considered to be elevated. The 75g-oGTT should then be carried out again on another day.
In this case, the patient has to be fasted and a fasting blood sugar determined. A sugar solution with 75g glucose is then drunk. After 2 hours another blood sample is taken to determine the blood sugar.

Read more on the subject at: Blood glucose testing

Can you do that yourself?

There are already attempts to develop such a test for at home. So far, however, the glucose tolerance test can only be carried out by a doctor. This is because it must be carried out accurately with the right amount of sugar and precisely adhering to the time intervals. In some practices, blood is also taken from the vein instead of using a finger prick in order to obtain a more precise value

Evaluation - these are normal values

The normal values ​​are:

• Fasting blood sugar below 92 mg / dl

• Value after one hour below 180mg / dl

• Value after two hours below 153mg / dl

If one of these limit values ​​is exceeded, gestational diabetes is suspected.

What should the value be after an hour?

In the glucose tolerance test during pregnancy, the value should be below 135 mg / dl one hour after drinking 50 g of glucose. If this value is exceeded, the 75g-oGTT should be carried out on another day in order to confirm or refute the suspicion of gestational diabetes.

Side effects

The glucose tolerance test has no serious side effects. Drinking the sugar solution can cause nausea and vomiting, as the solution is very sweet. Another side effect may be small bruises from the blood sample.

Can this be dangerous for my baby?

The glucose tolerance test does not pose a threat to the baby. In fact, it is a useful test, since undetected and untreated gestational diabetes can have consequences for the baby. With gestational diabetes, the child can grow faster. This has consequences such as increased oxygen consumption, respiratory distress syndrome during childbirth or the storage of glycogen in the heart muscle, which can lead to diseases of the heart muscle. The consequences of untreated diabetes can also be hypoglycaemia in the child after birth and an increased risk of malformations such as heart defects and malformations of the gastrointestinal tract.

Read more on the subject at: Gestational diabetes

Duration

Since the glucose tolerance test has to take into account a waiting time of one hour before the blood sugar is determined, about 90 minutes should be allowed for the entire test. The duration can of course vary depending on the waiting time in practice.

costs

The cost of the glucose tolerance test is around 20 euros. However, the costs are covered by the health insurance company as part of the preventive check-ups for pregnant women.

Does the health insurance pay for that?

Since 2012, the costs for the glucose tolerance test during pregnancy have been covered by the health insurance companies as part of the preventive medical checkups for pregnant women. If the value is increased, the costs for the 75g-oGTT are also taken over. However, if 75g-oGTT is carried out without the 50g-oGTT pre-test, as is sometimes recommended by doctors, the health insurance company will not pay for this test.

What are the alternatives?

If there are risk factors for gestational diabetes, such as diabetes in relatives or gestational diabetes in previous pregnancies, the fasting blood sugar can be measured before the 24th week of pregnancy.

There is no alternative examination to detect gestational diabetes.