Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
In pregnancy, it's usually done between 24 and 28 weeks.
A 1-hour screening test is often done first; a longer test follows if it's high.
Why it's done
- Checking for gestational diabetes
- Diagnosing prediabetes or diabetes when other tests are unclear
Getting ready and what happens
- For the 2- or 3-hour test, fast for 8 to 14 hours beforehand.
- Eat your normal diet in the days before.
- Plan to sit quietly during the test; walking and smoking can affect results.
How the test is done
- Blood is drawn before (for fasting tests) and at set times after you drink the glucose liquid.
What the results mean
| Result | Typical range for adults |
|---|---|
| 1-hour pregnancy screen | Below about 130 to 140 mg/dL (depends on the clinic) |
| 2-hour test, not pregnant | Below 140 mg/dL is normal; 140 to 199 prediabetes; 200 or higher diabetes |
Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.
High screening result
A high 1-hour screen doesn't mean you have gestational diabetes. It means you need the longer test.
Gestational diabetes
Usually managed with diet, activity, and blood sugar checks, sometimes with insulin. It usually goes away after delivery, but raises future diabetes risk.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
- What happens if my screen is high?
- When should I be tested after delivery?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related medicines
Related tests
Sources
Last updated 2026-11-13.