How Bad Is the Pregnancy Glucose Test, Really? We Asked an Ob-Gyn

AsiaVision | Getty
AsiaVision | Getty

Pregnancy can be a roller coaster of screenings, tests, and health check-ups to ensure you and the baby are happy and healthy. One of these routine prenatal checks is the pregnancy glucose test, which screens for gestational diabetes. It's a relatively common condition that affects up to 10 percent of pregnancies in the United States every year, according to the CDC. But issues can arise with the baby's development if it goes undiagnosed.

Gestational diabetes is a condition some pregnant people can experience if their pancreas doesn't produce enough insulin to control their glucose levels. Symptoms can include intensive thirst, frequent urination, fatigue, blurred vision, and bladder, kidney, or skin infections, according to Emily Volk, MD, FCAP, president of the College of American Pathologists. Leaving the condition untreated puts you at a higher risk for pregnancy-related hypertension, also known as preeclampsia, and can impact the baby's development. Also, "Too much glucose in the urine can be damaging to the kidneys over time," Dr. Volk says.

A pregnancy glucose test can help your provider know early on whether or not you're at risk for gestational diabetes. And if you are at risk, they can create a treatment plan that keeps you and baby safe. While there may be some fear around the pregnancy glucose test (it usually involves drinking a not-so-tasty sugary beverage to measure the body's response to sugar), it's a normal part of the pregnancy-care journey. Keep reading for a breakdown on what to expect from a glucose test during pregnancy in addition to expert tips on how to prepare for it.

What Is a Pregnancy Glucose Test?

A pregnancy glucose test, otherwise known as an oral glucose-tolerance test, is a way to screen for gestational diabetes. It's considered a normal part of prenatal care. "Doctors will send pregnant women 24 to 28 weeks to a lab where they'll drink a very sugary liquid that kinda tastes like Cola if you've added six tablespoons of sugar," Dr. Volk explains. "It's a very sweet concoction that needs to be chugged down. It's purposely a load of sugar so the results can show us how their body reacts to it." The drinks come in different flavors, with lemon/lime and orange flavors being fairly common. "In my personal experience, the drinks honestly all taste terrible — especially when you're pregnant — but it's a little better to drink them chilled," Alison Cowan, MD, ob-gyn, head of medical affairs at Mirvie, says.

An hour after you drink the glucose solution, the lab tech will draw your blood and check the blood glucose levels. "We see how high it is and if it's within normal limits, then that means your pancreas is making enough insulin to appropriately manage your blood sugar levels," Dr. Volk says. If the test is abnormally high, a three-hour test is ordered as the diagnostic test. "In this case, you do not need to follow any particular diet leading up to the test (and should eat carbohydrates normally in the days prior)," Dr. Cowan says. But you will need to fast for at least eight hours before the three-hour test. When you go to the lab for this test, they will draw your blood four times: after fasting, and then one, two, and three hours after you drink the sugary beverage. The diagnostic test shows to what degree the pancreas is not working.

How Do you Prepare For a Pregnancy Glucose Test?

You do not need to fast for the standard one-hour glucose test, but you cannot eat or drink anything during the hour between the time you drink the beverage and the time your blood is drawn, according to Dr. Cowan. The three-hour test does require fasting eight hours prior to the test. And "to make things extra confusing, there is also a 2-hour one-step diagnostic test that some providers use," Dr. Cowan says. Either way, they're all fairly similar in that they involve drinking a sweetened drink with a prescribed amount of glucose in order to see how your body responds to and processes sugar. "If your body isn't able to process the glucose as efficiently, your measured blood glucose will be elevated, which is how we make the diagnosis of diabetes in pregnancy," Dr. Cowan says.

I Didn't Pass the Pregnancy Glucose Test, What Now?

"Gestational diabetes is very common and it's manageable, so the first thing to do if you don't pass your 3-hour is not to panic," Dr. Cowan says. "Most moms and babies do very well, and there are a lot of dietary changes (and medication if needed) that can help." Your doctor will write a prescription for a glucose meter to check your blood sugars at home and will help provide you with nutritional information to eat a consistent, controlled amount of carbohydrates with each meal and snack. They will also monitor your blood sugar with you to see whether you might need medication to improve your blood sugar levels, in addition to monitoring the baby's growth during the pregnancy. After delivery many people with gestational diabetes will not go on to have diabetes. However, if you're diagnosed with gestational diabetes, it will be important to be screened regularly for Type 2 diabetes for the rest of your life. "Pregnancy health is lifetime health," Dr. Cowan says. "Women with diabetes in pregnancy can have up to a 50% chance of eventually developing Type 2 diabetes." The good news is that there is a lot that you can do to prevent that once you know you're at risk.

Each pregnant person should heed the advice of their OBGYN. But regardless of who you decide to receive prenatal care from, it's important to get tested. "Just make time to do it. It's important for you, your baby and the rest of your family," Dr. Volk says.