Gestational Diabetes Diagnosis

Gestational diabetes diagnosis generally occurs as a result of routine testing during pregnancy. Pre-natal care from an experienced midwife or obstetritian is important because it can help to avoid problems before they occur or to diagnose them early so that they can be dealt with. Gestational diabetes is one of these problems which can occur during pregnancy and without testing and treatment can negatively affect the health of both the mother and the baby.

Testing for gestational diabetes is considered part of the routine screening and care in the pre-natal period. However, when and if testing occurs is up to the discretion of each womans treating physician or midwife. Generally, the decision is based on the woman's risk for developing gestational diabetes.

Most patients, who have average risk for diabetes during pregnancy, will have a routine screening test for glucose levels in the blood early in the 3rd trimester of pregnancy, usually around 24 to 28 weeks of gestation. If a woman is believed to be of higher risk, for example if she has had a previous pregnancy with gestational diabetes, then testing may be done earlier or even at the first pre-natal visit. If a woman is believed to be very low risk, some doctors may decide that testing is unnecessary.

When testing is done, the goal is to make a gestational diabetes diagnosis early enough so that something can be done to control the blood glucose to prevent the complications that can be associated with gestational diabetes. The type of testing can vary. Single random blood samples of glucose can miss the diagnosis or wrongly diagnose diabetes. Fasting glucose levels are generally more accurate but generally the method considered the most sensitive and specific for making a gestational diabetes diagnosis is a fasting oral glucose tolerance test.

The oral glucose tolerance test is done after the woman has been fasting for at least 8 hours. Baseline gluose levels are tested and then she is instructed to drink a sugar solution which raises her blood glucose. Her blood levels are then tested at various time points, generally 1, 2 and 3 hours after the ingestion of the drink. In a normal pregnancy, the levels rise modestly initially but quickly return to normal levels. If levels are higher than the normal range and stay persistently high over time, this can help make the diagnosis of gestation diabetes.

If you are concerned about gestational diabetes and your risk, ask your own treating physician or midwife if you should be tested.