Insulin is produced by the pancreas. If the pancreas does not produce enough insulin, the carbohydrates cannot be used and the level increases in the blood. The carbohydrate that is tested and found in the blood is glucose. Excess glucose in the blood leads to the diagnosis of diabetes. If diabetes is not adequately controlled by diet or insulin injections, complications can occur, such as increases in infections and damage to blood vessels.
When a woman is pregnant, she must share her carbohydrates with the growing baby. The pregnancy hormones can interfere with the ability of the mother’s insulin to regulate carbohydrates.
In a small percentage of pregnant women (3-12%), the insulin response is very reduced and the blood glucose levels become abnormally high, causing gestational diabetes (diabetes in pregnancy). For the mother, this can mean increased risk of infections or increased chance of a Cesarean section delivery. Following delivery of the baby, the mother’s system returns to normal.
In addition to problems for the mother, her baby may also suffer from diabetes. Depending upon the blood levels of glucose during the pregnancy, the baby may grow excessively large, causing difficulties at delivery. Additionally, the baby may have temporary difficulty controlling its glucose and calcium at birth. If the mother’s blood sugar remains elevated throughout her pregnancy, the baby has increased risk of stillbirth.
DETECTING GESTATIONAL DIABETES
Gestational diabetes is most often encountered in late pregnancy. In the past, screening for this disease was based on clues such as a family history of diabetes, history of delivery of a baby weighing more than nine pounds, a history of stillbirth or certain birth defects, high blood pressure, obesity, or age over thirty at the time of delivery. However, because many women develop gestational diabetes without any of these risk factors, screening for gestational diabetes is now performed for all pregnant women between 24 and 28 weeks of pregnancy.
One Hour Glucose Tolerance Test (Glucola or Kolodex)
When you arrive for the test, you’ll be given a sugar solution that contains 50 grams of glucose. The solution like a very sweet soda pop (it comes in cola, orange, or lime flavor), and you have to get all of it down in five minutes. We do keep it chilled so that you may drink it cold. An hour later, we will take a blood sample from your arm to check your blood sugar level.
If the reading is abnormal (too high), which happens 15 to 23 percent of the time, your practitioner will have you come back for a three-hour glucose tolerance test to see if you really do have gestational diabetes. The good news is that most women whose screening test shows elevated blood sugar don’t turn out to have gestational diabetes.
Will this test make me feel sick?
Some moms-to-be feel nauseated after drinking the glucose solution, and a few even throw up. It sometimes helps to have eaten something a few hours before the screening test. If you vomit soon after you’ve gotten the drink down, you’ll have to come back another day and repeat the test. But most women get through it just fine. It’s actually more common for women to feel sick during the three-hour glucose tolerance test, because the solution for that test may be twice as sweet, or contain twice as much liquid as the one for the screening test, and you have to drink that one on an empty stomach.
What is an abnormal blood glucose level?
Current guidelines state that if your one-hour blood sugar level is 130 milligrams of glucose per deciliter of blood plasma (mg/dL) or more, you need to have the glucose tolerance test. If your blood glucose level for this test is higher than 200 mg/dL, we consider you to have gestational diabetes and you won’t be required to take the glucose tolerance test. But any score between 130 and 200 means that you’ll have to take the three-hour glucose tolerance test for a definite diagnosis.
Three Hour Glucose Tolerance Test
For three days before the test, you’ll have to begin a special diet of at least 150 grams of carbohydrates per day.
Glucose Tolerance Testing Diet
You will eat three meals per day and have a bedtime snack, and your meals should consist of at least 50% carbohydrates. 10 servings of carbohydrates equal approximately 150 grams of carbohydrates. You may check the package nutrition labels on most foods, as most labels will indicate the number of grams of carbohydrates the food contains. You must have at least 150 grams of carbohydrates each day for three days prior to your test.
The following are examples of one serving of carbohydrates (you should eat approximately 10 per day for the three days prior to your test):
Meat, fish, poultry, cheese, eggs, butter, and oils contain very little or no carbohydrates, so eating these foods will not help you reach your goal of 150 grams of carbohydrates per day, and they may fill you up so that you have difficulty eating the ten servings of carbohydrates that you need. Avoid all caffeine for three days prior to your test.
Do not eat or drink after 12 midnight the night prior to your test. You may have sips of water only. Do not exercise for 8 to 12 hours prior to your test. Medications such as aspirin (salicylates), diuretics, and anticonvulsants decrease insulin secretion and should be avoided for at least 3 days prior to the test. CHECK WITH YOUR PHYSICIAN BEFORE STOPPING ANY MEDICATIONS. If you have any questions, please do not hesitate to call our office at (757) 722-7401.
Glucose Tolerance Test (3 Hour Test) – Testing Day
When you arrive for the test, the technician will take a blood sample to measure your “fasting blood glucose level” and then ask you to drink either a more concentrated dose or a larger volume of the glucose solution. Then brace yourself for three more arm pricks, as your blood is tested every hour for the next three hours. The technician should alternate arms each time she draws your blood.
You’ll definitely need something to distract you this time, because you’ll have to stay seated in the waiting room between blood drawings (bring a book!). We will provide you with a snack and juice to eat right after your final blood sample is drawn because you’ll probably be starving.
If one of the readings is abnormal, you may have to take another test later in your pregnancy. Or your practitioner may ask you to make some changes in your diet and exercise routine. If two or more of your readings are abnormal, you’ll be diagnosed with gestational diabetes and you’ll need to talk to your practitioner about a treatment plan. This chart shows the levels that the American Diabetes Association considers abnormal at each interval of the test:
95 mg/dl or higher
180 mg/dl or higher
155 mg/dl or higher
140 mg/dl or higher
What happens if I’m diagnosed with gestational diabetes?
You’ll work with your practitioner and a gestational diabetes specialist and nutritionist to come up with a plan to manage your condition. Your condition should only last as long as your pregnancy – but a small number of women who develop diabetes during pregnancy still have it after delivery, so you’ll have to take another glucose test after six weeks postpartum.
Because you had gestational diabetes while you were pregnant, you will need to be retested for diabetes after your baby is born. The test will be performed at your six-week postpartum visit.
Please do not eat anything after midnight of the night before your scheduled test. You may drink plain water only. The test will take at least two hours; you will have a fasting blood sample drawn first. You will then be given a 75 gm dose of glucola. Your blood will be drawn again 1 hour after you finish drinking the glucola, and a third sample will be drawn 1 hour after the second draw.
If you have any questions, please feel free to call the office at 757-722-7401.
Important Information for You
Why do I need this test?
You had gestational diabetes during your pregnancy. This puts you at risk for having type 2 diabetes now or in your future. You may feel fine, but if diabetes is not treated, it can lead to heart disease, kidney failure, blindness, stroke, and early death. This blood sugar test will help to find out if you have type 2 diabetes.
What if the test is not normal?
If your blood sugar is high but not high enough to be called type 2 diabetes, you may have prediabetes. If so, you will need to have your blood sugar tested at least every year.
What if the test is normal?
You are still at greater risk than other women for having type 2 diabetes in the future. You need to be tested at least every 3 years. Tell your doctors. It is important to tell all of your doctors about the gestational diabetes that you had during your pregnancy so that you get this testing for type 2 diabetes in the future. It is important for you to also remember. Write yourself a note and mark it on your calendar.
What can I do now?
You can help to prevent or put off getting type 2 diabetes by breastfeeding your baby, by making smart food choices and by keeping active at least 30 minutes 5 days a week.
Here are some great places for more information:
American Diabetes Association: www.diabetes.org
Centers for Disease Control and Prevention’s (CDC) Diabetes Public Health resource: www.cdc.gov/diabetes
American College of Obstetricians and Gynecologists: www.acog.org
National Diabetes Education Program: www.ndep.nih.gov
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Fri: 8:30am – 1:00pm