When you’re approaching the end of your second trimester, your provider will schedule a special test to determine whether you have developed gestational diabetes during your pregnancy. Read on for more info about gestational diabetes, including what it is, how the glucose test works, and what the next steps will be if you are diagnosed.
What is Gestational Diabetes?
Gestational diabetes can develop during pregnancy in women who didn’t previously have diabetes, and affects 2-10% of all pregnancies. Gestational diabetes occurs when the hormone insulin—which helps to break down glucose from the food we eat—isn’t acting effectively. This causes sugar to build up in the blood and leads to diabetes.
The reason this happens during pregnancy? All of the hormones and other changes (such as weight gain) during pregnancy can interfere with the way insulin works in the body. This causes your body’s cells to use insulin less effectively, also known as insulin resistance. While all pregnant persons have some level of insulin resistance later in pregnancy, some begin their pregnancies with an already-increased need making them more susceptible to gestational diabetes. Gestational diabetes can also start when your body isn’t able to make and use the amount of insulin it needs during pregnancy. Without this insulin, it’s difficult for the body to properly regulate glucose levels.
While gestational diabetes can develop in any pregnant person, there are several risk factors that can increase your chances of this condition, including:
- Being overweight or obese
- Physical inactivity
- Gestational diabetes in a previous pregnancy
- High blood pressure
- A history of heart disease
- PCOS (polycystic ovary syndrome)
- A family history of type 2 diabetes
What Are the Risks of Gestational Diabetes?
First and foremost, if you are diagnosed with gestational diabetes it’s important to know it’s treatable and manageable by working with your provider. However, if not treated effectively, those diagnosed with gestational diabetes can increase their risk of high blood pressure, a C-section delivery, low blood sugar, and the potential to develop type 2 diabetes. Gestational diabetes can also affect your baby, potentially increasing their risk of premature birth, higher birth weight, and breathing problems.
How Do They Test for Gestational Diabetes?
Testing for gestational diabetes typically occurs somewhere between 24 and 28 weeks of pregnancy. However, if you have a higher risk you may be tested earlier. There are two routine tests that can help your provider diagnose gestational diabetes:
Glucose Challenge Screening
This screening is the first test you’ll take to determine if your body is processing sugar effectively. During this test you’ll quickly drink a special, sugary drink (typically containing 50 grams of sugar) in order to increase the amount of glucose in the body. An hour after finishing this drink, a lab technician will take a blood sample to test your blood sugar levels and ensure your body is processing glucose correctly and efficiently.
If your blood glucose levels are above 140 mg/dL after the one-hour test, your provider will likely recommend a second test, called a glucose tolerance test. If your blood glucose level is higher than 190 mg/dL, your provider may diagnose you with gestational diabetes.
Glucose Tolerance Test
In the days leading up to this more in-depth glucose test, your doctor may give you a special diet to follow, and instructions to fast (not eat) overnight before the test. Also known as the three-hour glucose test, your blood will be drawn to test your “fasting blood glucose level.” Then you’ll drink another highly sugary drink—typically containing 100 grams of sugar. After drinking it, your blood will be tested every hour for three hours in order to see how well your body processes the glucose. Because of the length and nature of the test, it’s a good idea to bring a healthy snack to eat after your final blood draw to prevent lightheadedness.
Normal blood glucose levels for the three-hour test are:
- Fasting: lower than 95 mg/dL
- After 1 hour: lower than 180 mg/dL
- After 2 hours: lower than 155 mg/dL
- After 3 hours: lower than 140 mg/dL
If one of the results is higher than normal, you may be asked to complete the test again in a few weeks. If two or more results are higher than normal, your provider may diagnose you with gestational diabetes.
What Happens After My Glucose Test?
Your provider will review the results of your glucose test, and inform you as to whether you’ve passed, require further testing, or are diagnosed with gestational diabetes. If you do have gestational diabetes, your provider will work closely with you to create a detailed treatment plan, including how to monitor and manage your blood sugar.
The good news is those diagnosed with gestational diabetes typically return to normal blood sugar levels once baby is delivered. Your provider will recommend any necessary follow-up care, and encourage you to focus on diet and exercise to help lower your risk of developing type 2 diabetes later in life.
We know any pregnancy complication can be unnerving, mama. But you’re in great hands! Your provider will help monitor and guide you throughout your pregnancy to ensure you and baby are as healthy as possible.