When you're growing another human, taking care of your body is arguably your number one priority. After all, if you're not healthy your future baby might not be healthy. (And forming-fetus aside, you deserve to be healthy regardless.) At the beginning of your third trimester, your doctor will order a glucose tolerance screening to test for gestational diabetes. It's best to be prepared and know what to eat before a gestational diabetes test, just so you get the most accurate results.
Because a test for gestational diabetes is all about measuring your blood sugar, it's important to know what you do and don't need to do to prepare. A gestational diabetes test actually isn't one test, either, but has two different parts, and whether or not you sit through the second part will depend on how well you do with the first. The first of the two tests is called the Glucose Screening Test or Glucose Challenge Test. There's no preparation needed for this test. If you test positive on that one, you will be required to do a second, longer test called a Glucose Tolerance Test. This test does require that you eat certain foods at certain times. Three days prior to the test you want to eat normally, but make sure to include 150 grams of carbohydrates per day, according to UW Health. The day of the test you can't eat or drink anything, except water, for at least eight hours and not more than 14 hours prior to the test, according to LabCorps. Because of this requirement, you might want to schedule the test early in the morning.
Why do you need to take these tests? When women are pregnant, there's a concern that they could develop gestational diabetes (literally, diabetes while pregnant) and high blood sugar levels can affect your baby's health. This happens in up to 9.2 percent of women, according to a study done by the Centers for Disease Control and Prevention (CDC). If your blood sugar is high, you could wind up with high blood pressure or preeclampsia, per the University of Wisconsin (UW). You also increase the risk of your baby being born premature or being really large, which isn't ideal. "A large baby born through the birth canal can injure nerves in his shoulder," the CDC stated, as well as, "break her collarbone; or, rarely, have brain damage from lack of oxygen."
Because of the potential danger, gestational diabetes testing is a standard part of prenatal care. If you are already diagnosed as a diabetic, BabyCenter reports that you do not need to take the test, but you will need to make sure you and your doctor have a plan to manage your diabetes during your pregnancy.
The first test, the Glucose Challenge test, will not diagnose diabetes, but it's a screening to see if you need further testing. It's usually given between 24 and 28 weeks gestation. Prep for this test is pretty non-existent, according to the American Pregnancy Association (APA). You just need to show up and take the test. It requires you to go to a lab, drink a sugary drink (provided by the lab), wait an hour, then get your blood tested to see how your body is processing sugar. The sugary drink tastes like really sweet soda and comes in different flavors, and you need to drink the whole thing fairly quickly. Many people say it's better served cold, so it may be helpful to call the lab before you go to see if it's refrigerated. If not, you could bring a cup of ice if you think it'll make it all go down easier.
If you have elevated sugars an hour after drinking the solution and, essentially, fail the Glucose Challenge Test, you need to go back to the lab on another day for a three hour Glucose Tolerance Test. Don't panic if this is you, as about a third of people who fail the first test do not actually have gestational diabetes.
The Glucose Tolerance Test needs to be done after 8-14 hours of fasting. It also requires you to drink a sugary drink when you get to the lab. You then get your blood drawn at one, two, and three hour intervals after the drink has been consumed. You definitely want to download some podcasts, bring books, or get ready for scrolling a lot of social media, as you need to wait in the lab between blood tests.
For both the Glucose Challenge Test and the Glucose Tolerance Test, UW Health suggested bringing a protein snack for after the test is over, as you may feel a little shaky afterwards.
Should your Glucose Tolerance Test come back positive, be calmed by the fact that gestational diabetes is manageable and usually goes away after you deliver. You will need to monitor your blood sugar via home testing, have more frequent doctor appointments, and maintain a healthy diet, and exercise. Some women may also need medication.
According to the Mayo Clinic, if you have gestational diabetes your blood sugar will be tested after delivery and again in six weeks. I's also important to follow up with your practitioner and to have your blood sugar levels tested regularly, as women who have gestational diabetes have a one in four chance of developing Type 2 diabetes later in life.
While it may seem like an inconvenience to have to take the time to drink a sweet drink, hang out in the lab waiting room, and then get a blood test, it's pretty wonderful that science can tell us if something in our pregnancy needs attention, so we can give our babies the best chance at being born healthy (and staying healthy ourselves).
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