Carbohydrate intolerance in pregnancy affects 12 – 15% of pregnant women and is due to the effects of placental hormones.
Oral glucose tolerance test (OGTT)
GDM is diagnosed on the 75-gram oral glucose tolerance test. A glucose challenge test (GCT) is no longer recommended.
How to prepare for the oral glucose tolerance test (OGTT):
The OGTT result may be misleading when:
In these cases, the 1-hour and 2-hour results may be falsely elevated. If she vomits the glucose drink, these results will be falsely normal or low. Either repeat the test with more optimal preparation or monitor glucose levels for 1- 2 weeks. Seeing at least 1 value above the target glucose levels in one week suggests a diagnosis of GDM.
When to perform the OGTT
Alternatives to OGTT
If women refuse to have an OGTT, she was unable to complete it or if the result is uncertain, there are alternative pathways to diagnosing GDM.
None of these are as accurate as the OGTT, so the results need to be considered carefully:
Postpartum OGTT and risk of Type 2 Diabetes
After delivery, women with GDM are at a higher risk of developing Type 2 Diabetes.
The recommendations for postpartum OGTT screening are:
The 10-year risk of developing type 2 diabetes is 50 – 70%.
This risk is reduced by: