A gestational diabetes test checks blood sugar, or glucose, levels during pregnancy. Before the test, people should avoid consuming food and drinks that are high in sugar and simple carbohydrates, as these may affect results.

High blood sugar levels in pregnancy can indicate gestational diabetes, which without treatment, could affect maternal and fetal health. People may also refer to the test as a glucose screening test or glucose challenge test.

A glucose tolerance test is a follow-up test that people may need if the initial test shows high blood sugar. This can confirm a diagnosis of gestational diabetes.

Avocado on wholewheat toast, which can be good to eat before a gestational diabetes test.Share on Pinterest
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People do not typically need to fastTrusted Source before a glucose screening test, and they can eat at the times they would normally eat. However, fasting may be necessary for those undergoing a glucose tolerance test.

A doctor will provide specific instructions on when a person can eat before their glucose test.

If people are having a glucose screening test in the morning, they can eat breakfast as usual. Healthcare professionals generally recommend eating a meal that is low in sugar and also contains complex carbohydrates and protein. This may include meals such as:

  • wholegrain toast with avocado or natural peanut butter
  • plain Greek yogurt with berries
  • oatmeal with low fat milk and nuts or sliced apple
  • scrambled eggs or omelet with broccoli or tomatoes

Before a glucose tolerance test, people can eat their usual diet in the days before as significant changes such as dieting may affect the test resultsTrusted Source and their reliability.

It is often recommended that people avoid simple carbohydrates and sugary foods and drinks on the morning of the glucose screening test. This includes items such asTrusted Source:

  • refined cereals
  • white bread
  • cakes, pastries, and other baked goods
  • syrups
  • fruit juice
  • soda
  • honey
  • white or brown sugar
  • candy

Certain foods, such as simple carbohydrates, can causeTrusted Source sudden increases in blood sugar. The body digests simple carbohydrates quickly and immediately releases glucose into the bloodstream.

It takes longer for the body to digest complex carbohydrates, meaning the glucose is released into the bloodstream more slowly. This avoids spikes in blood sugar and helps keep the levels stable.

If a person’s blood sugar spikes due to food, this may affect test results.

In some cases, people may have false-positive resultsTrusted Source from glucose screening. This occurs when a person has a raised blood sugar reading but does not have gestational diabetes.

Also, making major changes to the diet in the days before a test may affectTrusted Source results and the reliability of the test.

Aside from limiting simple carbohydrates and sugary food right before the test, people do not typically need to do anything to prepare for a glucose screening test.

However, a person may need to discontinue medications that are known to affect glucose intolerance. It is important to not stop taking any medications without discussing it with a doctor first.

People will need to avoid eating anything for at least 8 hoursTrusted Source before having a glucose tolerance test.

Normal results for a glucose screening test show blood sugar levels are at 140 mg/dL or lessTrusted Source. If a glucose screening test comes back positive, it shows that blood sugar levels are higher than 140 mg/dL.

In this case, a doctor will order a glucose tolerance test to confirm the results. If a glucose tolerance test also shows high blood sugar levels, a doctor will diagnose a person with gestational diabetes.

If a person has a gestational diabetes diagnosis, they will need to track their blood sugar and manage it with a balanced diet and regular physical activity.

A doctor will monitor people with more frequent prenatal appointments and prescribe any medications to manage blood sugar if necessary.

Gestational diabetes goes away after giving birth, although it can increase the risk of developing diabetes in the future.

Can I drink milk before a gestational glucose test?

People may be able to drink milk before a glucose test. Milk with lactose contains carbohydrates, so it will affect blood sugar levels. Lactose-free milk breaks down into simple sugars, which can also affect blood sugar.

Before a glucose tolerance test, people will only be able to drink water, as it requires a period of fasting beforehand.

Can I eat sugar the day before a gestational glucose test?

People can eat their usual dietTrusted Source in the days before a glucose test, but it is best to avoid sugary foods and refined carbohydrates shortly before the test.

People can speak with a doctor for specific guidelines on the best diet to follow before the test.

What is the best thing to eat before a gestational diabetes test?

People can eat a meal low in sugar, which contains complex carbohydrates and protein. It is best to avoid sugary drinks and refined carbohydrates, as these can increase blood sugar levels.

How can a person lower their blood sugar before a gestational diabetes test?

People can eat a balanced diet and avoid simple sugars and refined carbohydrates. Taking a walk before the test may also help.

Before a glucose screening to test for gestational diabetes, people should continue eating their usual diet. However, eating foods that are high in sugar and simple carbohydrates shortly before the test may affect the results.

People can eat breakfast as usual on the morning of the test. Eating complex carbohydrates and fiber may help manage blood sugar levels.

If the results of the glucose screening test suggest high blood sugar levels, a person may require a glucose tolerance test. Before taking this particular test, a person needs to fast. A doctor will be able to provide more detailed information.