The short explanation
The glucose tolerance test, often called GTT or OGTT, checks how your body handles sugar during pregnancy. Pregnancy hormones make the body less responsive to insulin, and in some women blood sugar rises higher than it should. This is gestational diabetes, and it is common in South Asian women. Fasting beforehand gives a starting reading that is not affected by food. You then drink a measured glucose solution, and blood is taken again after a set time to see how well your body brings the sugar back down. In India the test is often done at the first visit and repeated around the middle of pregnancy, but the exact plan varies by hospital.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- Follow the instructions you are given about fasting and timing, because eating or walking around a lot during the test can change the result.
- Feeling slightly sick after the sugary drink is common. Tell the staff if you vomit, because the test may need to be repeated.
- A family history of diabetes, being overweight, PCOS, a previous large baby or gestational diabetes in an earlier pregnancy raise the chance of a high result.
- The test is usually available at government hospitals and PHCs as part of antenatal care.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This cannot tell you what your result means. Only your clinician, looking at the actual numbers against the cut-offs they use, can explain that.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- Which test are you using and what are the cut-offs?
- What exactly should I do about food and water before the test?
- If my result is high, what happens next?
- Will I need to repeat it later in pregnancy?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Emergency — call 112 now
- Call 112 or go to the nearest emergency department if you feel faint and confused, have severe belly pain, or have heavy bleeding at any stage of pregnancy.
Book an appointment soon
- See your clinician within a few days of the test to go through the result.
Raise it at a routine appointment
- Book the glucose test at the time your antenatal team recommends.
Sources
The evidence this explanation is built on.
- Gestational diabetes NHS
- Diabetes and pregnancy MedlinePlus (US National Library of Medicine)
Who wrote and reviewed this
Every AskHer answer names its author. A clinically reviewed answer also names the clinician who signed it off — if no clinician is named below, it has not been clinically reviewed.
- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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