When you’re pregnant, you may wonder why your obstetrician asks for a urine sample at prenatal checkups. One thing your doctor watches is glucose. It may be normal for some to show up, but if it shows up repeatedly or in large amounts, it can be a sign that you have gestational diabetes (high blood sugar during pregnancy).
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Most women get screened for gestational diabetes between 24 and 28 weeks into their pregnancy. If there is a lot of glucose in your urine in early prenatal visits, however, you’ll probably do the screening sooner.
“For people who have risk factors for gestational diabetes, we usually recommend that they get screening early in pregnancy — usually in the first trimester,” says maternal-fetal medicine specialist Jeff Chapa, MD.
What are the risk factors?
Your doctor likely will talk to you about several risk factors during your early checkups. Dr. Chapa says you are more likely to get gestational diabetes if:
- You are overweight, with a body mass index over 30.
- You are over age 35.
- You had a baby that weighed more than 9 pounds.
- Your blood sugar levels are high in the urine or blood.
- Your family has a history of type 2 diabetes.
- You had gestational diabetes before.
- Women who have a few of these factors often get an early screening.
How does the screening work?
Your doctor will ask you to take a test called the oral glucose tolerance test. Here’s what happens:
- During the test, you quickly drink a sweetened liquid that contains 50 grams of glucose. Your body absorbs this glucose quickly, causing your blood sugar levels to rise.
- You will have blood drawn from your arm about 1 hour after drinking the sugary liquid. The blood test measures how well your body processes the glucose solution.
- If your test results are abnormal (high blood glucose level), you likely will have to take a similar but longer test, for which you will fast (not eat anything) before taking. This test involves drinking a liquid with 100 grams of glucose and your blood sugar is checked before you drink the glucose and every hour for three hours afterwards. If this test shows abnormal results, then you have gestational diabetes.
“When you’re screened early, if that screening is normal, you should get screened again around 24 to 28 weeks when insulin resistance from the placental hormones is at its peak,” he says.
The placenta is the organ that connects you to your baby to nourish it as it grows. Some hormones that the placenta makes work against the action of the insulin your body makes. As the placenta grows, so does this “insulin resistance.” In some people, this change is enough to cause the blood sugar level to be increased as it is in people with diabetes.
How can I reduce my risk of gestational diabetes?
There are no guarantees — and about half of women who get gestational diabetes don’t have any risk factors. But it’s always a good idea to adopt healthy habits.
- Watch what you eat: Your doctor or a nutritionist can help you make healthier choices in your diet. In general, eat less sugar and refined carbohydrates (white bread, white rice, pasta). Add more fiber to your diet (raw fruits and vegetables, whole grains, nuts and unsweetened nut butters).
- Step up your exercise: Talk to your doctor about what activities are best for you, but typically walking, swimming, yoga and other low-impact exercise is best.
What if gestational diabetes develops?
If you do get gestational diabetes, your doctor will monitor it throughout your pregnancy because it can cause problems for both you and your baby.
Since your body’s insulin supply cannot keep up, extra glucose stays in your blood and the baby receives more sugar than it needs — and stores it as fat. Possible outcomes include a large baby, more chance of a cesarean delivery, and a slightly higher risk of fetal and neonatal death.
Babies born to mothers with diabetes need their blood sugar levels monitored after birth. Low blood sugars can result in newborn babies from mothers with any type of diabetes, and this can lead to problems for your baby, including seizures, Dr. Chapa says.
However, you can still have a healthy baby if you focus on good habits. To ensure stable blood sugar levels:
- Monitor your blood glucose levels regularly.
- Limit the amount of carbohydrates and simple sugars in your diet.
- Exercise regularly.
For most women, blood sugar levels return to normal after delivery, but your doctor will likely check them during the postpartum period. About 10% of women with gestational diabetes have type 2 diabetes without knowing it.
If a woman has gestational diabetes, she also has a higher chance of developing type 2 diabetes later in life. About half of women with gestational diabetes will have type 2 diabetes in 10 years, so it is important for your primary care physician to closely monitor your blood sugars.
Gestational diabetes provides a warning for many women that they may on the way to developing type 2 diabetes, and it gives them a chance to make changes in their diet, weight (if they need to lose), and exercise to help prevent them from getting this disease.