OGTT in pregnancy-when should it be performed?

An OGTT (oral glucose tolerance test), or oral glucose load test, sometimes referred to by expectant mothers as a “sugar curve,” involves testing fasting blood glucose levels and then 60 and 120 minutes after drinking a solution containing 75 grams of sugar. For many women, this test is associated with unpleasantness, as nausea, vomiting or even fainting may occur after drinking this sweet solution. For this reason, between intakes you should not leave the clinic, but wait in the waiting room and, for example, read a book.

OGTT- preparation for the test

The first blood draw in the test must be done on an empty stomach. Therefore, a woman should eat her last meal about eight hours before her clinic visit. It is very important that this interval is not too long, because as a result of excessive starvation, blood glucose levels can rise and give a false test result. The mother-to-be for the test should report in the morning, rested and sleepy. Before visiting the clinic, make sure whether the facility provides a glucose solution to drink, or whether you need to purchase it yourself from a pharmacy.

OGTT-which week to perform?

OGTT is normally performed in pregnancy between 24. a 28. week of pregnancy. However, if the fasting glucose test results performed in earlier weeks were abnormal, the sugar curve is performed immediately, without waiting until the 24th. of the week. The same is true for women who have risk factors for gestational diabetes. Then, even despite normal fasting glucose levels in early pregnancy, an OGTT should be performed and then repeated between 24. a 28. week of pregnancy.

OGTT norms in pregnancy

Testing a woman’s blood glucose during an OGTT is done three times. The first blood is drawn on an empty stomach, and then one hour and two hours after drinking a glucose solution.

Normal blood glucose values in an oral glucose load test are:

• Fasting: less than 92 mg/dl ( <5.1 mmol/l),
• At 60 minutes: less than 180 mg/dl ( <10.0 mmol/l),
• At 120 minutes: less than 153 mg/dl ( ≤8.5 mmol/l)

If the values are abnormal, gestational diabetes is diagnosed.

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Gestational diabetes

Does flavored glucose interfere with the OGTT result?

For many pregnant women, the bland and sweet taste of glucose solution is associated with unpleasantness. That’s why drug manufacturers have introduced flavored glucose, which aims to be easier to assimilate compared to pure glucose. Available on the market include. Glucose  in orange or raspberry flavor. However, it is best to ask at your clinic whether such products are allowed in your area. Indeed, there is no clear position of the Polish Diabetes Association on the possible influence of flavored glucoses on the OGTT result. Some moms add lemon juice to the glucose, which is also supposed to offset the bland taste of the solution. As with flavored glucose, the easiest way is to ask your midwife or doctor if modifications can affect your OGTT and results.

Abnormal OGTT result

Abnormal values on the OGTT are indicative of diabetes. It may be the aforementioned gestational diabetes, which in most cases passes after the baby is born. However, it should not be underestimated, as it can carry serious complications. These include, but are not limited to: polyphagia, premature labor or hypertension in the pregnant woman. In turn, the child may develop excessive fat growth, resulting in macrosomia and, consequently, shoulder dystocia. Hypoglycemia at birth and respiratory distress are also frequently observed in newborns.

The OGTT, despite not being one of the most pleasant tests, is extremely important especially among pregnant women. Thanks to it, a complication of pregnancy such as gestational diabetes can be detected in time, which can then be controlled with diet or appropriate treatment and thus avoid serious possible complications.