When is the OGTT done in pregnancy?

The OGTT is commonly scheduled during the middle part of pregnancy, but your maternity team may arrange it earlier or later for individual reasons. Timing can depend on your medical history, an earlier glucose result, symptoms, or the way your service screens for gestational diabetes. Follow the appointment date and preparation instructions given to you rather than choosing a week from a general calendar.

Pregnancy changes how the body manages glucose, and those changes develop over time. Testing in the usual screening window helps the team assess glucose handling during that stage. If there is a reason to assess you sooner, your clinician may offer an earlier test or arrange another assessment later. An early normal result does not automatically answer whether later testing is needed.

Check whether fasting is required, whether medicines should be taken, and how long you need to remain at the clinic. Arrange transport or support if fasting makes you feel unwell, and bring food for afterward if permitted. Do not postpone the test because the timing differs from someone else's pregnancy. Learn more about the [Glucose Tolerance Test](/treatments/pregnancy-and-birth-care/glucose-tolerance-test/) and routine [Antenatal Care Package](/treatments/pregnancy-and-birth-care/antenatal-care-package/) follow-up.

Contact your maternity team if you have missed the arranged appointment, are unsure whether you should test now, or cannot follow the fasting instructions. Seek urgent advice for fainting, severe vomiting with dehydration, confusion, or sudden symptoms that feel serious. Do not wait for the planned OGTT if you are acutely unwell.

Why has this week been chosen for me? Do I need testing earlier or repeated later? Should I fast, and may I take my usual medicines? How long will the visit take? When and how will I receive the result?