When do you take the glucose test during pregnancy

Who Gets the Test?

All women should get glucose testing during pregnancy. It's a standard test. It's especially important if you're having twins, because your risk of diabetes is higher.

Table of Contents Show

Who Gets the Test?
What the Test Does
How the Test Is Done
What to Know About Test Results
How Often the Test Is Done During Your Pregnancy
Other Names for This Test
1-Hour Gestational Diabetes Screen
How do I prepare for my 1 hour glucose test?
Is a glucose test mandatory while pregnant?
How many times do you take a glucose test during pregnancy?
When should glucose test be done?

What the Test Does

Glucose testing checks for a type of diabetes that can start when you're pregnant. Gestational diabetes is common and treatable. It usually goes away after birth. Without treatment, it can cause problems during pregnancy.

There are few basic tests. The glucose challenge screening tests how your body is processing blood sugar. If the results are abnormal, you will get a follow-up test. It's called a glucose tolerance test. If that's positive, you'll get treatment to get your glucose under control and keep your baby healthy.

Some women also get a blood test to check glucose called the A1C.

How the Test Is Done

Glucose tests are harmless to you and your baby. During the glucose challenge screening, you'll drink a small amount of glucose. After an hour, a nurse or phlebotomist will take a blood sample.

For the follow-up glucose tolerance test, you'll have to adjust your diet for a few days. Then you'll fast for 8 to 14 hours before the test. A nurse or phlebotomist will test your blood and then give you glucose. After that, they will take three more blood samples over the next few hours.

The A1C test is a simple blood test to check long-term glucose levels.

What to Know About Test Results

If you do have a positive result, try not to worry too much. Diabetes during pregnancy is common. As many as 1 in 10 pregnant women get it. Most have normal pregnancies and healthy babies.

Your doctor may recommend extra testing to check on your baby. You will need to keep your blood sugar under control with diet, exercise, and sometimes medicine.

Women who have gestational diabetes have an increased risk of developing diabetes later in life.

How Often the Test Is Done During Your Pregnancy

Women get glucose testing at 26 to 28 weeks. Some women also get testing for glucose in early pregnancy if they have additional risk factors. If it turns out that you have diabetes, you'll get regular testing for the rest of your pregnancy. Your doctor may do an A1C blood test at your first prenatal check-up.

Other Names for This Test

Glucose challenge screening, glucose tolerance test, A1c test

1-Hour Gestational Diabetes Screen

The O’Sullivan test measures pregnant women’s body’s reaction to glucose (sugar). The test is administered between the 26-28 week mark during the pregnancy and is done to screen for gestational diabetes.

Gestational diabetes is a condition when women without diabetes develop high blood sugar levels while they are pregnant.

After going through the test, which is further explained below, you will know if your levels are below normal, normal, or above normal. If your levels are abnormal, you will need to schedule additional tests to confirm your diagnosis.

The values that are used to determine gestational diabetes were first detected by O’Sullivan and Mahan in 1964 during a study designed to be able to recognize the risk of developing type 2 diabetes. Later the test was informally named after O’Sullivan.

Video Transcription:
Hi, I’m Nicole, I’m a nurse here at Moreland OB-GYN and I‘m here to you about our two glucose tests that we do during pregnancy. These tests measure the pregnant women’s reaction to glucose and screen for gestational diabetes which is a condition when a woman that does not have diabetes ends up with elevated high glucose levels. Having elevated blood sugar during pregnancy can affect your baby and your delivery. Advanced maternal age, your activity level, being overweight, or having a family member with diabetes all are factors that can contribute to gestational diabetes. First, I will explain the 1-hour glucose test, otherwise known as O’Sullivan Testing. You will be given a drink, like this, typically at your 24-week prenatal visit. You will be expected to drink the liquid prior to your next visit between 26 and 28 weeks of pregnancy. You need to drink this within 5 minutes, and then you will have to have your blood drawn one hour from that time. What does the drink taste like? It’s very sweet so we recommend drinking it straight from the fridge so it’s nice and cold to help control that sweetness. It is recommended to avoid foods or snacks that are high in sugar prior to the test. A normal or negative test result means you do not have gestational diabetes. However, an abnormal or positive test result means you are at risk for having gestational diabetes and we will need you to do the three-hour glucose test. So how does the three-hour test work? There are multiple blood draws for the three-hour glucose test, the first after fasting for 8-12 hours. Then you will be given a similar glucose liquid to drink and blood samples will be taken at 1, 2, and 3 hours after completing that drink. Because activity can interfere with the results, you will need to stay in the lab during the duration of the test, so we recommend bringing something to read, a project to work on, something to watch while you are waiting. You may drink plain water during the test however no food can be consumed at the time. Bring a snack for after cause you may be quite hungry. Based on the results of this test and other criteria that your doctor uses, you will be given a diagnosis. If you’re positive after this test, your physician will provide you information and other resources on how to manage your gestational diabetes. We hope this video gave you an overview of the testing performed to check for gestational diabetes. We have additional information on our website – Moreland o-b-g-n dot com, and if you still want more information, please ask your physician at your next visit. As always, it's our job here at Moreland to lead women to better health.

Why am I Having This Test? How is This Test Done?

You will be given a drink containing glucose from your physician. This is usually given to you when you are around 24 weeks to drink prior to your 28-week appointment. It is recommended you put the drink in the refrigerator; it seems to taste better cold.

You are directed to drink the entire bottle within 5 minutes.
You will then need to have your blood drawn 1 hour after completing the drink.
It is recommended showing up to the lab at least 15 minutes prior to the 1-hour time limit, just in case there is a wait – lab will not draw you if you are over the 1-hour limit and you will have to do the drink again.

What Do I Do On The Day of The Test?

On the day of testing, avoid foods or snacks that are high in sugar, otherwise, you should eat normally. Time your blood draw to complete the test prior to your physician appointment. Your blood needs to be drawn exactly 1 hour from completion of the glucola drink. Make sure you alert lab personnel that you are there for a timed diabetic test and the time you are due to be tested.

Looking for more helpful tips? Download your pregnancy planning kit, now!

What Do The Test Results Mean?

A normal or negative result means that you do not have gestational diabetes. An abnormal or positive result means that you are at risk for gestational diabetes and an additional test, called a 3-hour glucose tolerance test, will need to be performed. You will be given specific instructions should you need to have this test done.

How do I prepare for my 1 hour glucose test?

DO NOT eat or drink anything (other than sips of water) for 8 to 14 hours before your test. (You also cannot eat during the test.) You will be asked to drink a liquid that contains glucose, 100 grams (g) . You will have blood drawn before you drink the liquid, and again 3 more times every 60 minutes after you drink it.

Is a glucose test mandatory while pregnant?

Doctors recommend having a glucose test for gestational diabetes, but it's not mandatory.

How many times do you take a glucose test during pregnancy?

The American College of Obstetricians and Gynecologists recommends performing a one-hour blood glucose challenge test to screen for gestational diabetes in low-risk pregnant women between 24 and 28 weeks of pregnancy.

When should glucose test be done?

You may need to test only before breakfast and sometimes before dinner or at bedtime if you use just an intermediate- or a long-acting insulin. If you manage type 2 diabetes with noninsulin medications or with diet and exercise alone, you may not need to test your blood sugar daily.