Diagnosis of Gestational Diabetes
If you are at high risk of developing gestational diabetes (for example, obese , prior history of gestational diabetes, family history of diabetes), your doctor may recommend that you undergo glucose testing at your first prenatal visit. If your initial test is negative, you will be tested again later in your pregnancy. If you are at an average risk of developing gestational diabetes, your doctor will do a screening test between 24-28 weeks of gestation.There are different tests that can be used to diagnose gestational diabetes. These tests measure the level of glucose in your blood.
Glucose Tolerance TestIf your doctor has ordered the 100 gram glucose tolerance test, you will need to follow special dietary restrictions:
- Three days before the test, eat a diet that contains at least 150 grams of carbohydrates a day.
- For 10-14 hours before the test, do not eat or drink anything, except water.
|Time||Blood glucose values|
|Fasting||95 mg/dL (5.3 mmol/L)|
|1 hour||180 mg/dL (10 mmol/L)|
|2 hours||155 mg/dL (8.6 mmol/L)|
|3 hours||140 mg/dL (7.8 mmol/L)|
Other TestsIn addition to the above screening tests, additional tests may include:
- HbA1c test (shows average glucose levels the past 2-4 months)
- Urine tests
- Thyroid function tests
- Tests to monitor the fetus (for example, ultrasound )
Gestational diabetes mellitus (GDM). EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated July 11, 2012. Accessed August 17, 2012.
Screening and diagnosis of gestational diabetes mellitus. Committee Opinion No. 504. American Congress of Obstetricians and Gynecologists. Obstet Gynecol. 2011;118:751-753.
What I need to know about gestational diabetes. National Diabetes Information Clearinghouse (NDIC) website. Available at: http://diabetes.niddk.nih.gov/dm/pubs/gestational/#7. Updated December 6, 2011. Accessed August 17, 2012.
- Reviewer: Andrea Chisholm, MD
- Review Date: 09/2014
- Update Date: 09/17/2014