Gestational diabetes mellitus (GDM), also simply called gestational diabetes, is a condition where develop high blood sugar levels during pregnancy. It affects people who have never been diagnosed with diabetes and usually appears between 24 and 28 weeks of pregnancy.
According to the International Diabetes Federation (IDF), 1 in 6 live births worldwide is associated with high blood sugar levels during pregnancy. That is about 21 million live births.
What causes gestational diabetes?
When you eat food containing carbohydrates, they are broken down into simpler sugars, including glucose. Glucose is absorbed into the blood, from where it can be distributed into your cells and used to make energy.
After a meal, the pancreas, a large gland in your abdomen, produces a hormone called insulin which tells your cells to take up glucose from your blood. During pregnancy, your cells are slightly resistant to insulin. This allows your blood to have more glucose for the developing baby to take up.
In the middle of your pregnancy, your placenta releases increased amounts of certain hormones into your blood. These hormones maintain your pregnancy but can also affect how well your cells respond to insulin, worsening the existing insulin resistance. Glucose does not enter the cells as it should, so it accumulates in your blood and you get gestational diabetes.
What are the types of gestational diabetes?
There are 2 classes of gestational diabetes. They are:
- Class A1: In this class, diet modification is enough to control blood sugar levels.
- Class A2: Here, insulin or oral anti-diabetes medications are needed to manage the diabetes.
What are the symptoms of gestational diabetes?
Gestational diabetes does not usually cause any symptoms. Most people find out that they have the condition after a routine screening test. In case you have symptoms, they may be mild and may include:
- Excessive thirst
- Frequent urination
- Fatigue
- Blurred vision
- Nausea
What are the risk factors of gestational diabetes?
Anyone who is pregnant can get gestational diabetes. You may have higher chances of getting the condition if you:
- Were overweight or obese before you became pregnant
- Have high blood pressure
- Have polycystic ovarian syndrome (PCOS)
- Have a family history of diabetes
- Have had gestational diabetes in an earlier pregnancy
- Have given birth to a baby weighing more than 9 pounds(4kg) before
- Are not physically active
- Have heart disease
- Are older than 40 years
- Have signs of insulin resistance such as acanthosis nigricans, a condition where you have dark, velvety patches on the skin, most commonly in body folds.
- Are Asian American or African American
What are the complications of gestational diabetes?
When the condition is not managed, the high blood sugar levels can affect you and your baby before, during and after delivery.
Gestational diabetes can increase your chances of:
- High blood pressure during pregnancy (preeclampsia)
- Cesarean delivery
- Developing type 2 diabetes
- Urinary tract infections
- Preterm birth
Gestational diabetes can increase your baby’s chances of:
- High birth weight (fetal macrosomia)
- Birth injuries
- Low blood sugar (hypoglycemia)
- Breathing problems
- Jaundice
- Developing diabetes later in life
- Heart disease
How is gestational diabetes diagnosed?
Your doctor will do blood tests to check for gestational diabetes when you’re 24–28 weeks pregnant, or earlier if you have risk factors for the condition.
Diagnosing the condition is usually a 2-step process. Your doctor will do an initial screening test, and follow it up with a second test if you fail the first one. The tests that may be done include:
- Glucose challenge test
This is the initial test and is also called a one-hour glucose tolerance test.
You are given a drink containing 50g of glucose and after 1 hour, a nurse, or phlebotomist will collect a blood sample from your vein. This sample is used to measure your blood sugar levels. If your blood sugar is below 135mg/dl, you will not have the second test done. If otherwise, your doctor will schedule the second test on a separate day.
- Glucose tolerance test
This second test is also called a two-hour or three-hour oral glucose tolerance test.
After an overnight fast (at least 8 hours), your doctor will measure your fasting blood sugar levels. Thereafter, you will be given a drink containing 100g of glucose. Your blood sugar levels will be tested at 1 hour, 2 hours, then 3 hours later.
Your doctor will diagnose you will diagnose you with diabetes if you have 2 or more of the following values:
- Fasting blood sugar level of 95mg/dl or more
- 1-hour blood sugar level of 180mg/dl or more
- 2-hour blood sugar level of 155mg/dl or more
- 3-hour blood sugar level of 140mg/dl or more
A 1-step testing approach can also be used to diagnose gestational diabetes. Here, your doctor skips the glucose challenge test and does only the two-hour oral glucose tolerance test. After an 8-hour fast, your blood sugar levels are measured. You are given a drink with 75g of glucose and your blood sugar levels measured 1 hour and 2 hours later.
You will be diagnosed with gestational diabetes if you have any of:
- Fasting blood sugar levels of 92mg/dl or more
- 1-hour blood sugar levels of 180mg/dl or more
- 2-hour blood sugar levels of 153mg/dl or more
How is gestational diabetes treated?
Treatment for gestational diabetes involves different strategies, which may include:
- Monitoring blood sugar levels
Your doctor may usually recommend that you monitor your blood sugar levels 4 or more times a day. The schedule typically involves checking blood sugar levels in the morning after an overnight fast, then 1 to 2 hours after each meal. You will need to have a glucose meter (glucometer), test strips, needles (lancets) and cotton swabs. Your doctor will explain to you how to use these tools to self-test your sugar levels.
You can record the values in a book, on a piece of paper or an application. These levels may be used to adjust your diet or medications.
The healthy blood sugar targets recommended by the American Diabetes of Association (ADA) and the American College of Obstetricians and Gynecologists (ACOG) are:
- Fasting blood sugar level of less than 85mg/dl
- 1-hour blood sugar level of less than 140mg/dl
- 2-hour blood sugar level of less than 120mg/dl
- Physical activity
Engaging in a moderate-intensity exercise at least 5 days a week, 30 minutes each day, may also help you to control your blood sugar levels. You can choose to fraction your exercise into 10-minute rounds.
You need to avoid contact sports and activities that increase the pressure inside your abdomen, such as lifting heavy weights, jumping, and so on. Remember to always stay well hydrated during the exercise rounds.
- Dietary management
Eating a balanced diet consisting of appropriate amounts of protein, fat, carbohydrates, and fiber can help keep you healthy while managing your blood sugar levels. You may need to eat small, frequent meals. You may also be advised to eat less refined sugars such as those in sugary drinks, cake, cookies, and other processed foods. These are digested and absorbed more easily and are more likely to increase your blood sugar levels.
- Medications
Your doctor may prescribe insulin to help you control your blood sugar levels. A nurse or doctor will explain how to inject yourself with insulin, how much to take, and when to take it. The dose of insulin may change depending on your blood sugar levels.
You may need to take oral medications as part of your treatment. Metformin and glyburide (glibenclamide) are the anti-diabetes medications that can be used to treat gestational diabetes.
What should I remember?
Gestational diabetes is a temporary condition that occurs during pregnancy, affecting both mother and baby. It is important to manage it through a healthy diet, regular exercise, and, if necessary, medication. Proper management helps prevent complications like high birth weight and preterm delivery.
Early detection and consistent care are key to ensuring a healthy pregnancy and delivery. After giving birth, monitoring blood sugar levels remains essential, as gestational diabetes increases the risk of developing type 2 diabetes later in life. Making informed choices can protect your health and your baby’s well-being.
