Final answer:
The Glucose Tolerance Test (GTT) is used to screen for gestational diabetes mellitus (GDM) in pregnant women.
Step-by-step explanation:
Understanding Glucose Tolerance Test in Pregnancy
The Glucose Tolerance Test (GTT) is a crucial screening tool used in pregnancy to identify gestational diabetes mellitus (GDM), a condition characterized by hyperglycemia that is first recognized during pregnancy.
A positive result on a GTT during pregnancy, particularly a GTT reading that is higher than the normal fasting blood glucose levels of 70 to 130 mg/dL, warrants further evaluation to determine the appropriate treatment. Diabetes mellitus is diagnosed in individuals with a fasting blood glucose level higher than 125 mg/dL.
In the context of pregnancy, specific thresholds may be lower, as recommended by obstetric guidelines, and any result above the established cutoff should be followed by additional tests to ascertain the presence of GDM.
The GTT is administered after the patient follows a carbohydrate-rich diet for three days. The test begins with a fasting blood glucose measurement, followed by consumption of a glucose solution and periodic blood glucose measurements thereafter.
If a pregnant woman's blood glucose levels remain elevated beyond the expected timeframe, it suggests an impaired ability to regulate blood glucose, indicative of GDM.
Continued hyperglycemia post-GTT may also lead to differentiation between the types of diabetes—insulin-dependent or independent—through additional tests such as the Insulin Tolerance Test (ITT) and the Glucagon Tolerance Test (GuTT).