The 1-hour glucose test is a common screening tool used during pregnancy to identify individuals who might be at risk for gestational diabetes. This condition involves high blood sugar levels that develop during pregnancy in women who did not previously have diabetes. Detecting and managing gestational diabetes is important for the well-being of both the pregnant person and the developing baby. Early identification allows healthcare providers to implement strategies that support a healthy pregnancy outcome.
Preparing for the Test
Preparing for the 1-hour glucose test does not require extensive changes to your routine. Fasting is typically not necessary; you can usually eat a normal breakfast or lunch before the test, depending on your appointment time. However, it is advisable to avoid foods high in concentrated sugars, such as candy, sugary cereals, or fruit juices, immediately before the test to prevent falsely elevated results. Some healthcare providers might suggest eating a meal low in carbohydrates before the test.
Maintain your usual diet in the days leading up to the test, as restricting food intake can affect the accuracy of the results. Stay hydrated by drinking plain water. If you are taking any medications, discuss these with your healthcare provider, though it is usually not necessary to stop them for this particular test.
The Test Process
Upon arriving at the clinic or lab for your 1-hour glucose test, you will typically inform the staff that you are there for the screening. The first step involves consuming a specific glucose solution, usually containing 50 grams of sugar. You will be instructed to drink the entire bottle of this sweet liquid within a short timeframe, often within five minutes. Many facilities keep the solution chilled, which some individuals find makes it easier to drink.
After consuming the glucose drink, you will need to remain in the clinic or lab for exactly one hour. During this waiting period, it is important not to eat or drink anything other than plain water. Chewing gum, mints, or smoking should also be avoided, as these can influence your blood sugar levels. Movement and activity can also impact the results, so you will generally be asked to rest quietly.
Precisely one hour after you finish the drink, a blood sample will be drawn from a vein in your arm. This sample measures how your body has processed the sugar from the solution.
Understanding Your Results
The results of your 1-hour glucose test indicate how efficiently your body processes sugar. A blood sugar level below 140 milligrams per deciliter (mg/dL), or 7.8 millimoles per liter (mmol/L), is typically considered within the normal range. If your result falls within this range, it usually means you do not have gestational diabetes, and no further testing is immediately needed. It is worth noting that some healthcare providers or labs may use a slightly lower threshold, such as 130 mg/dL (7.2 mmol/L), to determine if further testing is warranted.
A result that is above the normal range, commonly between 140 mg/dL and 190 mg/dL, does not automatically mean you have gestational diabetes. Instead, an elevated result suggests your body may not be processing sugar effectively, indicating a need for further, more comprehensive testing. If your blood sugar level is significantly high, such as 190 mg/dL or greater, your healthcare provider might diagnose gestational diabetes directly, bypassing further screening.
What Comes Next
If your 1-hour glucose test results are elevated, the next step is typically a 3-hour glucose tolerance test (GTT). This diagnostic test provides a more detailed assessment of your body’s sugar processing. Unlike the 1-hour screening, the 3-hour GTT requires fasting for 8 to 14 hours, with only sips of water permitted.
During the 3-hour GTT, a baseline blood sample is drawn after fasting. You then consume a glucose solution, typically 100 grams of sugar, which is higher than the screening test. Subsequent blood samples are taken at one, two, and three hours after the drink.
Remaining in the clinic throughout this multi-hour process is important, as physical activity can influence the results. Your healthcare provider will review the 3-hour GTT results to determine if you have gestational diabetes and discuss the appropriate course of action. It is common for individuals with an elevated 1-hour screening result to not be diagnosed with gestational diabetes after the 3-hour test.