Understanding Gestational Diabetes Mellitus (GDM)

Gestational diabetes is a condition characterised by elevated blood sugar levels that arise specifically during pregnancy and typically resolve after childbirth.

Gestational diabetes can occur at any point during pregnancy. However, it tends to be more prevalent in the second or third trimester.

Risk factors for developing gestational diabetes

The risk factors for developing gestational diabetes in certain women include being over 40 years old when pregnant, obesity, history of having a baby with a birth weight of 4.5kg or more, and history of gestational diabetes during a previous pregnancy.

Other risk factors include having a strong family history of diabetes, underlying condition like polycystic ovarian syndrome (PCOS), and having undergone gastric bypass or other weight-loss surgery.

Symptoms of gestational diabetes

Typically, gestational diabetes is asymptomatic, and most cases are only discovered during screening for gestational diabetes.

However, in some women, they may experience symptoms if their blood sugar levels are elevated (hyperglycaemia) such as increased thirst, frequent urination (more than usual), dry mouth, tiredness, and genital itching.

Do take note that some of these symptoms can be common in pregnancy and may not necessarily indicate gestational diabetes. Therefore, if you have concerns about any symptoms mentioned above, do consult your doctor.

Possible complications of gestational diabetes

Most women with gestational diabetes experience otherwise normal pregnancies and give birth to healthy babies.

However, there are some possible complications:

• Having a larger than usual baby that increases the likelihood of delivery by Caesarean section.
• Polyhydramnios that may cause premature labour.
• Increased risk of premature birth (delivering a baby before completing 37 weeks of pregnancy).
• Pre-eclampsia, which is a condition of high blood pressure during pregnancy and can cause complications if not addressed early.
• Baby may experience low blood sugar or develop jaundice (yellowing of the skin and eyes) after birth, which could necessitate medical treatment in a hospital.

Stillbirth (a baby who dies before being born) is a complication that has become increasingly rare in women with gestational diabetes due to effective blood sugar control and meticulous monitoring of both mothers and babies throughout pregnancy.

Mothers who have gestational diabetes also have an increased risk of developing type 2 diabetes later.

Diagnosis of gestational diabetes

Testing for gestational diabetes is typically conducted between the 24th and 28th weeks of pregnancy. Nevertheless, if the pregnant mother has risk factors for gestational diabetes, testing may be initiated as early as your initial prenatal appointment.

Testing for gestational diabetes can be done in one of these two ways: two-part test or one-part test.

Two-part test

On the day of the initial screening test, maintain your regular diet and fluid intake. You will be given a 50-gram glucose solution in the form of an orange or cola drink, which you should consume within a few minutes.

An hour later, your blood sugar level will be measured:

• If your blood sugar is within the normal range, no further tests are necessary.
• If your blood sugar level is above 130 to 140 mg/dL (7.2 to 7.7 mmol/L), it is considered high.
• If your blood sugar level is ≥200 mg/dL (11.1 mmol/L), this very high reading strongly indicates gestational diabetes.

If your initial screening result is high but not very high, you will need a follow-up test known as an oral glucose tolerance test (GTT). This involves measuring your fasting blood sugar level in the morning and then at one, two, and three hours after drinking a 100-gram glucose solution (twice the amount in the one-hour test), which is also usually in the form of an orange or cola drink.

Do not to restrict your diet in the days leading up to the GTT, as limited food intake could lead to falsely elevated results. 

Gestational diabetes is diagnosed if two or more blood sugar values during the GTT are elevated. However, some doctors may recommend treatment even after a single elevated result, especially if other signs of gestational diabetes are present, such as a larger-than-average foetus or excess amniotic fluid.

One-part test

Some doctors use a different type of oral GTT. This test involves measuring your fasting blood sugar level in the morning and then at one and two hours after drinking a 75-gram glucose solution, typically in the form of a specially formulated orange or cola drink.

Gestational diabetes is diagnosed if one or more blood sugar values are elevated.

Treatment options for gestational diabetes

If you are diagnosed with gestational diabetes, it is necessary to make lifestyle adjustments and learn to monitor your blood sugar level.

1. Eating right

   The first treatment for gestational diabetes is eating right. Continue with a healthy pregnancy diet and maintain your commitment to a nutritious diet during pregnancy. Follow the general guidelines below until you receive your individualised food plan.

   Eat frequent, balanced meals. Consume three small-sized meals and incorporate three to four healthy snacks into your daily eating routine. Aim to eat every two to three hours to evenly distribute your food intake throughout the day. Avoid skipping meals. Paying attention to a bedtime snack can help regulate your fasting blood sugar levels.

   Avoid sugary treats and pre-sweetened beverages. Use alternative sweeteners in moderation.

   Include protein sources with low saturated fat content, such as lean cuts of red meat, pork, chicken, and fish. However, be mindful of the types and amounts of fish you consume due to concerns about mercury. Other protein-rich foods like cheese, eggs, nuts, seeds, and peanut butter are also beneficial.

   Consume moderate portions of carbohydrates. Limit fruit servings to a small piece of fruit or approximately 1 cup at a time. Include a variety of vegetables like salads, greens (spinach, collards, and kale), broccoli, green beans, carrots, tomatoes, mushrooms, and other vegetables that you enjoy.

   Choose healthy fats such as olive or canola oil can in your cooking and meal preparation.

2. Blood sugar monitoring

   You should ideally check your blood sugar 4 times a day - before eating in the morning, and one or two hours after breakfast, lunch, and dinner.

3. Exercise

   Exercise is not a mandatory component of gestational diabetes treatment, but it can be beneficial in managing blood sugar levels.

   If you were already engaged in an exercise routine before being diagnosed with gestational diabetes, it is generally recommended to continue exercising. If you did not have a regular exercise routine before, it is advisable to consult with your doctor or nurse to determine if exercise is suitable for you during pregnancy.

   In most cases, women without medical or pregnancy-related complications can engage in at least moderate exercise throughout their pregnancy.

4. Insulin

   Around 15% of women with gestational diabetes may need insulin - a medication that helps lower blood sugar levels, which in turn can help reduce the risk of complications associated with gestational diabetes. Insulin is given by injection, and you may require one or two shots depending on your dose. 

5. Oral anti-hyperglycaemic medication

   For women who are unwilling or unable to adhere to insulin therapy, oral anti-hyperglycaemic medication can be considered, provided they fully comprehend the limited information available regarding the long-term risks and benefits of these medications.

Make an appointment at Gleneagles Hospitals

If you suspect that you are experiencing symptoms of gestational diabetes during your pregnancy, get in touch with us to find out more about our Obstetrics & Gynaecology Services at your nearest Gleneagles Hospital.

You may also contact the Health Screening Centre at your nearest Gleneagles Hospital for health screening appointments