Testing for Gestational Diabetes (GCT)
In late pregnancy, your body will block insulin to make sure some of the glucose in your diet stays in your blood and circulates to the baby. Ideally, it’s the goldilocks model — you don’t leave too much glucose in your blood; your blood sugar is “just right.” If you keep too much glucose circulating in your blood to pass off to the baby, it would be a sign of Gestational Diabetes.
Step 1: Everyone gets screened with a Glucose Challenge Test (GCT) between 24-28 weeks.
Step 2: If your blood sugar is elevated in the Challenge Test you will be referred for a Glucose Tolerance Test (GTT) so we can determine if you have diabetes.
Step 3: If your blood sugar is elevated in the Glucose Tolerance Test, you will be diagnosed with Gestational Diabetes and have a plan to manage your glucose.
Goldilocks - "Just Right" blood sugar in pregnancy
This article includes information about who may get gestational diabetes, how we test for it, why we test for it. and what happens if the first test comes back with high blood sugar.
Who May Have Gestational Diabetes?
There are some women who are just naturally at greater risk of gestational diabetes. Your risk increases if you
are over 35-years old,
are overweight,
·have had a baby who weighs more than 9 lbs,
re Latin American, Asian, or African, or
have PCOS.
What are the risks?
When you have gestational diabetes, the cells are already saturated with glucose, so no new nutrition can be moved into the mother’s cells. So, in an odd way, too much sugar actually reduces nutrition for the mother while also over-feeding the baby.
When glucose stays in the blood, elevated blood sugars irritate the blood vessels the same way that a sugar scrub could irritate a tender area of skin if you scrubbed for an extended amount of time. High blood sugar can damage the placenta, which can affect the baby.
Possible risks to the baby include: too much glucose causing increased weight gain, shoulder dystocia or birth injury, difficulty breathing at birth, and unstable sugar in the immediate postpartum requiring medical care. If the inflammation affects the blood vessels in the placenta, the baby can be deprived of oxygen and nutrition which can lead to significant issues including jaundice, low calcium, and potentially stillbirth.
How do you test for gestational diabetes?
Glucose Challenge Test: The standard of care is to test all pregnant women at 24-28 weeks. This first test involves having the woman drink 50 grams of glucose. We will provide you the free bottle of “glucola” from Quest, or you can purchase a dehydrated food-sourced glucose for $20.
Drink the glucose 45-minutes before your next appointment. That gives us 15 minutes to get settled in, then we draw your blood. (we have to draw it 1 hour after you eat).
We should get your results back within a day or 2. If your blood glucose is 140 or above, you will need an extended glucose test called a Glucose Tolerance Test to determine if you have Gestational Diabetes.
Glucose Tolerance Testing: For that test, you’ll have your labs drawn at a Quest lab. They will give you a bottle of 100 gram glucose. Then they will draw your labs 3 times - one each hour after you drink it.
As an alternative to the longer testing, you can commit to 2 weeks of logging everything you eat, and recording your glucose 4x a day on a form we provide.
Continuous Glucose Monitoring: We can order a Freestyle Libre 3 Continuous Glucose Monitoring device for you to apply to your arm. You download the app. The device will monitor the amount of glucose in your interstitial tissues. You will write down everything you eat and drink, and also record your blood sugar 4x a day on the diet journal. At your next prenatal appointment we will look at your nutrition and your glucose readings and devise a plan.
Summary
We know that this process of testing for blood sugar is a little cumbersome. Please don’t get too far ahead of yourself. If your tests come back showing us that you need a little metabolic support, we will work together to support you and the baby. Until then, we are doing what needs to be done — studying your health.
