Diagnosing Gestational Diabetes: Glucose Tolerance Test and Blood Glucose Level Guidelines

Gestational diabetes is a temporary form of insulin resistance that usually occurs halfway through a pregnancy. It results from excessive hormone production in the body, or the inability of the pancreas to make the additional insulin that is needed during pregnancy in women.  In order to diagnose a pregnant woman with gestational diabetes, the healthcare provider will order a test from the lab.  There are two levels of the test that can be taken – the 1 hour glucose tolerance test and the 3 hour glucose tolerance test. 

The one hour test involves taking a blood sample after overnight fasting and then drinking a beverage with a known amount of glucose and testing your blood glucose again one hour later.  With the three hour version, you proceed the same, except the drink has a higher concentration of sugar and your blood is tested each hour for three hours instead of one.  The purpose of these tests is to see how your body reacts to and processes the large amount of sugar.

The American Diabetes Association lists the following blood glucose levels that would indicate gestational diabetes is present:

• Fasting 95 mg/dl or higher
• One hour 180 mg/dl or higher
• Two hours 155 mg/dl or higher
• Three hours 140 mg/dl or higher

If any two of the above readings come back in the ranges indicated you will be diagnosed with gestational diabetes.  Once you have been diagnosed, you doctor will provide you with the blood glucose guidelines that should be maintained for the optimal health of you and your baby.  They are:

• First thing in the morning – below 95 mg/dl
• One hour after a meal – below 140 mg/dl
• Two hours after a meal – below 120 mg/dl

There will be occasions when your blood sugar reading is higher than the recommended range.  In that case, adjust your next meal.  If you had planned on having a meal that was higher in carbohydrates, it should be changed so that there is more protein. Protein helps to lower your blood sugar and carbohydrates convert to sugar raising your glucose levels.

Check your blood glucose levels with Control D regularly to manage your Diabetes.