Gestational Diabetes

Diabetes During Pregnancy

What Is Gestational Diabetes?

Gestational diabetes sometimes develops when a woman is pregnant. It’s when the blood glucose level (blood sugar level) of the mother goes too high during pregnancy.

Having an elevated blood glucose level during pregnancy can cause problems for your baby—if it’s left untreated. Fortunately, doctors are vigilant about checking for gestational diabetes so that it can be identified and effectively managed. A pro-active treatment plan helps you have a good pregnancy and protects the health of your baby.

Gestational Diabetes Symptoms

Gestational diabetes doesn’t often cause noticeable symptoms for the mother. Other types of diabetes (eg, type 1 diabetes or type 2 diabetes) do cause symptoms such as increased thirst, but that is hardly ever noticed in gestational diabetes.

Because there aren’t often symptoms, it’s very important to be tested for a high blood glucose level when you’re pregnant. (Your doctor will most likely test you for gestational diabetes sometime between the 24th and 28th week. You can learn more about the diagnostic process here.) Then your doctor will know if you need to be treated for gestational diabetes.

Gestational Diabetes Causes and Risk Factors

Gestational diabetes develops when your body isn’t able to produce enough of the hormone insulin during pregnancy. Insulin is necessary to transport glucose—what your body uses for energy—into the cells. Without enough insulin, you can build up too much glucose in your blood, leading to a higher-than-normal blood glucose level and perhaps gestational diabetes.

The elevated blood glucose level in gestational diabetes is caused by hormones released by the placenta during pregnancy. The placenta produces a hormone called the human placental lactogen (HPL), also known as human chorionic somatomammotropic (HCS). It’s similar to growth hormone (so it helps the baby grow), but it actually modifies the mother’s metabolism and how she processes carbohydrates and lipids. HPL actually raises the mother’s blood glucose level and makes her body less sensitive to insulin—less able to use it properly. If the body doesn’t use insulin as it should, the blood glucose level goes up. The HPL hormone elevates the blood glucose level so that the baby gets enough nutrients from the extra glucose in the blood.

At 15 weeks, another hormone that affects the mother’s blood glucose level increases production: human placental growth hormone. This hormone helps regulate the mother’s blood glucose level, again to make sure that the baby gets enough nutrients. It can, however, cause the blood glucose level in the mother to go too high.

It’s normal for women’s blood glucose levels to go up a bit during pregnancy because of the extra hormones produced by the placenta. However, sometimes, the blood glucose level is too elevated.

The medical community isn’t sure why some women develop gestational diabetes, although there are several risk factors that make it more likely that you will develop it:

  • Age: Women over the age of 25 are more likely to get gestational diabetes.
  • Weight: Women who are overweight (have a body mass index—or BMI—that’s above 25) are more at risk for gestational diabetes.
  • Race/ethnicity: Gestational diabetes is more common within certain ethnic groups. African-Americans, Native Americans, Asian Americans, Hispanic people, and Pacific Islanders are more likely to have gestational diabetes.
  • Family history: If someone else in your family has or had diabetes (type 1, type 2, or gestational diabetes), you’re at higher risk.
  • Pre-diabetes: This is a “pre-diagnosis” of diabetes. It means that your blood glucose levels are elevated, but they aren’t high enough to be considered diabetes yet. If you’ve been told that you have pre-diabetes, you’re more likely to develop gestational diabetes.
  • Previous pregnancies with gestational diabetes: If you developed gestational diabetes during another pregnancy, you’re more at risk for developing it again.

Diagnosis

Gestational diabetes is diagnosed by checking your blood glucose level. Before doing that, your doctor will probably review your risk level and what risk factors you have; this is part of routine screening for gestational diabetes.

If the doctor feels you are at high risk for developing gestational diabetes, he or she will probably check your blood glucose level early in the pregnancy—sometimes as soon as they confirm that you’re pregnant.

If you aren’t at high risk, most doctors check the blood glucose level in the second trimester—around 24 to 28 weeks.

To diagnose gestational diabetes, your doctor will use the oral glucose tolerance test.  He or she will give you instructions on how to prepare for the test, but you won’t be able to eat anything for 8 hours before the test; you’ll be fasting.  This test is often done in the morning after an overnight fast.

On the day of the test, the doctor will test your blood glucose level at the beginning of the appointment; that’s called your fasting blood glucose level.

Then, you’ll drink 75 g of a very sugary mixture. Every hour for the next 2 hours, your blood glucose level will be measured.

If your blood glucose level is elevated (above normal) one or more times during the test, you have gestational diabetes.

The American Diabetes Association has set the following “above-normal” levels:

  • Fasting:  At or above 92 mg/dL
  • 1 Hour:  At or above 180 mg/dL
  • 2 Hour:  At or above 153 mg/dL

How Gestational Diabetes Can Affect Your Baby

When you have gestational diabetes, you must tightly control your blood glucose level. Talk to your healthcare professional regarding your individual blood glucose goals. Poorly controlled blood glucose levels—that stay too high for too long—can cause complications for your baby. 

Just because you’ve been diagnosed with gestational diabetes, that isn’t a guarantee that your baby will have all (or even any) of these complications. This is a list of what may happen if you don’t manage gestational diabetes.

Here’s how gestational diabetes can affect your baby at birth and right after birth:

  • Excess growth (macrosomia): Gestational diabetes may cause your baby to be very big and have extra fat. This can make delivery challenging because a bigger baby is more likely to become wedged in the birth canal, or you may need a C-section to deliver safely.
  • Low blood glucose (hypoglycemia): Right after the baby is born, the blood glucose level may drop very low (hypoglycemia) because they have so much insulin in their bodies. The extra glucose in your body actually stimulates the baby’s body to make more insulin, so when the baby is out the womb, the extra insulin can cause problems. Hypoglycemia in babies is easily treated by giving the baby a glucose solution to quickly raise the blood glucose level. Feeding the baby should also raise the blood glucose level.
  • Difficulty breathing (respiratory distress syndrome): Sometimes, babies have trouble breathing on their own right after they’re born, and this breathing difficulty is more likely in babies whose mother has gestational diabetes. This should go away after the lungs become stronger.

Here’s how gestational diabetes can affect your child later on:

  • Development problems: Researchers have noticed that children whose mothers had gestational diabetes are at a higher risk for developmental problems, such as language development and motor skill development.
  • Type 2 diabetes: Babies born of mothers with gestational diabetes are at a higher risk for developing type 2 diabetes later in life.

How Gestational Diabetes Can Affect You

As mentioned above, gestational diabetes often comes with no symptoms, so you probably won’t know that you have it until the doctor diagnoses it. However, gestational diabetes can still have an effect on you. 

Gestational diabetes can increase your risk of high blood pressure while you’re pregnant. Also, you may have a larger baby, which can make delivery difficult or require a C-section.

Gestational diabetes can also put you more at risk for developing type 2 diabetes later in life.

Gestational Diabetes Treatments

Treating gestational diabetes comes down to one main thing: controlling your blood glucose level so that it doesn’t go too high. You can control your blood glucose level by eating well, exercising, and perhaps taking insulin or another medication. Not every woman with gestational diabetes has to take a medication or insulin.

  • Eating well: A registered dietitian (RD) or certified diabetes educator (CDE) can help you create a meal plan that’s full of good-for-you and good-for-the-baby foods. The goal of the meal plan is to control your blood glucose level and keep it in the healthy, normal range. Your meal plan will be made just for you, taking into account your overall health, physical activity, and what you like to eat.

    For more information on what goes into the meal plan and what you can eat, read our article on the healthy meal planning with diabetes.
  • Exercise: When you exercise, your body uses more glucose, so exercising can lower your blood glucose level. Also when you exercise, your body doesn’t need as much insulin to transport the glucose; your body becomes less insulin resistant. Since your body isn’t using insulin well when you have gestational diabetes, a lower insulin resistance is a very good thing.

    And of course, there are all the traditional benefits of exercise: it can help you control your weight during pregnancy, keep your heart healthy, make you sleep better, and even improve your mood.

    Exercise doesn’t have to mean running a marathon. After checking with your doctor about what’s all right to do while you’re pregnant, try to get 30 minutes of exercise every day. That can be walking, jogging, or swimming. Even walking through the grocery store aisles counts as exercise, as does doing yardwork or housework. The point is to be active.
  • Medications/Insulin: You will first try to control your blood glucose level through diet and exercise. If you need a little extra help, the doctor may prescribe insulin or another medication to help your body regulate the blood glucose level. These cannot hurt your baby. The doctor, nurse, or your diabetes educator will explain how to take insulin or the medication.

You’ll know how you’re doing controlling your blood glucose level by monitoring it several times per day. The doctor, a nurse, or a certified diabetes educator will explain how to use a blood glucose monitor, and they’ll give detailed instructions on when you should check your level. You’ll also be asked to keep track of your daily levels—that helps both you and the doctor know how you’re doing.

Delivery When You Have Gestational Diabetes

When you’re delivering your baby, the doctor will watch your blood glucose level. If your level goes too high during labor, the baby may release more insulin in response. That increases the risk of the baby developing low blood glucose (hypoglycemia) after birth.

You may need to have a C-section if your baby is too large.

Will Gestational Diabetes Go Away?

Most likely, after you deliver your baby, gestational diabetes should go away. About six weeks after delivery, your doctor will check your blood glucose level to see if it’s in the normal range again.

However, because you had gestational diabetes, you’re at a higher risk (a 33-50% increased risk) for having it again in another pregnancy. You’re also at a higher risk for developing type 2 diabetes. To learn how to prevent type 2 diabetes, read our article on prevention.

 

View Sources
  • American Diabetes Association.  Standards of Medical Care in Diabetes—2012. Diabetes Care. 2012;35(S1):S11-63. doi: 10.2337/dc12-s011.
  • American Diabetes Association.  What is gestational diabetes? Diabetes Care.  2007;30:S105-111.
  • Ottawa Histology website.  The placenta.  Available at:  http://www.courseweb.uottawa.ca/medicine-histology/English/Reproduction/Placenta/Default.htm.  Accessed April 30, 2009.