What Is A Passing Score On The 1 Hour Glucose Test?

A passing score on the 1-hour glucose test is a blood sugar level below 140 mg/dL. That number is the most common cutoff used in the United States. Some clinics use a stricter threshold of 130 mg/dL instead. If your result lands at or above the cutoff your clinic uses, the test is considered positive, and you will usually be asked to come back for a longer follow-up test.

The 1-hour glucose test is a screening tool, not a diagnosis. It is designed to catch people who need a closer look, not to confirm gestational diabetes on its own. Understanding what the number means, and what happens next, takes some of the fear out of a result that comes back high.

What Is A Passing Score On The 1 Hour Glucose Test?

A passing score is any result below your clinic’s cutoff, most often 140 mg/dL. Results below that number mean the screening did not flag you for further testing.

The test works like this. You drink a sweet solution containing 50 grams of glucose. One hour later, a lab draws your blood and measures how much sugar is still circulating. In a normal pregnancy, the body releases insulin to move that sugar out of the bloodstream and into cells. If insulin is not keeping up, blood sugar stays higher than expected, and the screening catches it.

Two cutoffs are in wide use. The American College of Obstetricians and Gynecologists notes that a threshold of 140 mg/dL catches more cases but produces more false positives. A threshold of 130 mg/dL catches fewer cases but sends fewer people for follow-up testing. Neither number is wrong. They simply trade sensitivity for fewer unnecessary retests.

One detail worth knowing: the 1-hour test is a screening test, not a diagnostic one. A positive screen does not mean you have gestational diabetes. It means you need a more accurate test to find out.

What Happens If Your Result Is Above the Cutoff?

A result at or above the cutoff means you will be scheduled for a 3-hour glucose tolerance test. This is the diagnostic test, and it is the one that can actually confirm or rule out gestational diabetes.

The 3-hour test is longer and more involved. You fast overnight, then have your blood drawn before drinking a 100-gram glucose solution. Blood is drawn again at one, two, and three hours. Two or more elevated readings are generally needed to diagnose gestational diabetes.

It helps to know that most people who screen positive on the 1-hour test do not end up with gestational diabetes. The 1-hour test is deliberately set to cast a wide net. A high result is a signal to look closer, not a verdict.

Why Do Clinics Use Different Cutoff Numbers?

There is no single national standard for the 1-hour test cutoff, and that surprises many people. The choice comes down to how a clinic weighs two competing risks.

A lower cutoff catches more true cases but flags more healthy people who then need the longer test. A higher cutoff misses some cases but spares more people an unnecessary follow-up. Professional guidelines leave room for either approach, which is why two clinics in the same city may use different numbers.

What matters most is that you know your own clinic’s cutoff. If you are told your result was “borderline,” ask what number the lab used and what that number means for your next step.

What Can Affect Your 1-Hour Result?

Several things can push a result up or down that have nothing to do with gestational diabetes. Knowing them helps you interpret your number in context.

• What you ate beforehand. Some clinics ask you to fast, others do not. A recent meal can raise your reading.
• How long you waited. The test is timed at exactly one hour. A longer gap between drinking the solution and the blood draw can inflate the result.
• Illness or stress. Infection, fever, and physical stress can raise blood sugar temporarily.
• Certain medications. Some drugs, including certain steroids, can affect glucose levels.
• Activity level. Being unusually inactive right before the test may affect the reading.

If any of these applied on the day of your test, mention it to your provider. It may change how they interpret a borderline result.

What Does a Normal Blood Sugar Range Look Like in Pregnancy?

Outside of testing, normal fasting blood sugar generally falls between 70 and 99 mg/dL. During pregnancy, the body naturally becomes less sensitive to insulin, especially in the second and third trimesters. This is a normal hormonal shift, not a sign that something is wrong.

The placenta releases hormones that make it harder for insulin to do its job. Most pregnant people produce enough extra insulin to compensate. When the body cannot keep up, blood sugar rises, and that is when gestational diabetes can develop.

This is why screening happens later in pregnancy rather than at the first visit. The insulin resistance builds over time, so a test early on might miss a problem that develops weeks later.

How Common Is Gestational Diabetes?

Gestational diabetes is common, and it is manageable. It affects a meaningful share of pregnancies in the United States, and rates have risen over recent decades alongside shifts in maternal age and weight.

Most people who develop it can manage their blood sugar through diet, activity, and monitoring. Some need medication, often insulin. The condition usually resolves after delivery, though it does raise the risk of type 2 diabetes later in life, which is why follow-up testing after birth matters.

One point worth clarifying: gestational diabetes is not caused by eating too much sugar during pregnancy. It reflects how the body handles glucose under the hormonal pressure of pregnancy. Diet and activity can influence management, but the underlying cause is physiological.

What Should You Do With Your Result?

Read your number against your clinic’s specific cutoff, not a number you found online. If your result is below the cutoff, the screening is done. If it is at or above, the next step is the 3-hour test.

Ask your provider three things: what cutoff the lab uses, what your exact number was, and what the recommended next step is. Those three answers tell you everything you need to know about where you stand.