# Glucose Challenge Test (1-hour)

Source: https://www.pregnancypowerhour.com/tests/glucose-challenge-test
Last updated: 2026-07-01

> The 1-hour glucose challenge test is a common screening in the second trimester to check for gestational diabetes, typically done between weeks 24 and 28.

The 1-hour Glucose Challenge Test, often referred to as the glucola test, is a universal screening designed to identify individuals who might be developing gestational diabetes during pregnancy. This condition, if left unmanaged, can impact both your well-being and your baby's development. Understanding this test can bring a sense of clarity and confidence as you navigate your second trimester.

## What it is

This test is a screening tool, not a diagnostic one. Its purpose is to flag those who might benefit from further investigation for gestational diabetes (GD). GD is a type of diabetes that develops during pregnancy in people who haven't had diabetes before. It's important to remember that a positive screening result doesn't mean you have GD; it simply suggests that a more definitive test is warranted. This approach allows for early identification and management, supporting a calm and healthy pregnancy experience.

## When and how it happens

The 1-hour Glucose Challenge Test is typically recommended between weeks 24 and 28 of pregnancy. However, for individuals with certain risk factors—such as a BMI over 30, a prior history of gestational diabetes, a family history of diabetes, or specific ethnic backgrounds—earlier screening might be suggested, sometimes as early as your first prenatal visit. Your care provider is your best resource for your specific situation. 

The process is quite straightforward: you'll be asked to drink a 50-gram glucose solution. This solution, sometimes called "glucola," is designed to temporarily raise your blood sugar. One hour after you finish the drink, a blood sample will be drawn. There's no fasting required for this particular test, which can make it a bit more convenient than some other blood tests you might encounter, like those for your [Quad Screen / Triple Screen](/tests/quad-screen).

While the standard approach involves the glucose solution, some research has explored alternatives like consuming a specific amount of jellybeans (around 28 jellybeans equate to approximately 50g of glucose). However, not all labs universally accept these alternatives, so it's always worth discussing options with your provider if you have concerns about the standard solution. 

## What the results mean

After your blood is drawn, the lab will measure your blood glucose level. A threshold of 140 mg/dL is typically used in the United States to indicate a positive screen, though some centers might use a slightly lower threshold of 130 mg/dL. If your result is at or above this threshold, it means your body didn't process the sugar as expected within that hour. This positive screen does not confirm a diagnosis of gestational diabetes. Instead, it prompts a follow-up diagnostic test: the [3-hour Glucose Tolerance Test](/tests/glucose-tolerance-test).

It's helpful to know that about one-third of individuals who have a positive 1-hour screen are later confirmed to have GD by the 3-hour test. This highlights why the 1-hour test is a screening, designed to cast a wide net. It's also worth noting that guidelines can vary internationally. For instance, while the US (ACOG) often uses a two-step approach (1-hour GCT then 3-hour OGTT), other regions like the UK (NICE) or those following WHO IADPSG guidelines might use a single, one-step oral glucose tolerance test for screening. You get to decide which approach feels most aligned with your preferences and your provider's recommendations. Just like when considering your [Anatomy Scan](/tests/anatomy-scan), understanding the purpose and implications of each test helps you make informed decisions.

## Questions worth asking

Having a clear understanding of your prenatal care helps you feel more confident. Here are some questions you might consider asking your care provider about the 1-hour glucose challenge test:

*   What specific threshold does your practice use for a positive screen?
*   Are there any alternatives to the standard glucose solution that your lab accepts?
*   What are the next steps if my screening result is positive, and what would that process look like?
*   What resources are available if I am diagnosed with gestational diabetes?
*   How would this test fit into my overall pregnancy care plan?