What is gestational diabetes?

Diabetes is a condition in which there’s too much glucose in the blood.

Gestational diabetes is a type of diabetes that comes on in pregnancy.

What causes gestational diabetes?

The levels of glucose in the blood are normally controlled by a hormone called insulin. In gestational diabetes, hormonal changes during pregnancy mean the body doesn’t respond to insulin properly. This creates high levels of insulin, and it also means that the body can’t turn glucose into energy.

When the body can’t turn glucose into energy, glucose builds up in blood. This is the high blood sugar that most people think of when they hear about diabetes.

High blood sugar in pregnancy can create a lot of health risks for you and your baby unless it’s treated.

What are the health risks of gestational diabetes?

Gestational diabetes can increase the risk of a pregnant woman:

• having high blood pressure
• developing pre-eclampsia
• needing to be induced
• needing a caesarean section
• developing type 2 diabetes in the future.

It can also increase the risk of a baby:

• being born at a higher birthweight than expected
• having low blood glucose levels soon after delivery
• needing specialist care
• developing type-2 diabetes in the future.

Who might get gestational diabetes?

Around 1 in 5 pregnant women develop gestational diabetes, and some pregnant women are more likely to get it than others.

This includes women who:

• are pregnant at 35 years or older
• have previously had gestational diabetes
• have an Aboriginal, Torres Strait Islander, Indian, Vietnamese, Chinese, Middle Eastern, Hispanic, South American, Polynesian or Melanesian background
• have an immediate family member with type 2 diabetes
• have a body mass index (BMI) above 25
• have previously given birth to a baby with a birth weight over 4.5 kg
• have polycystic ovarian syndrome (PCOS)
• take medicines like antipsychotics or corticosteroids.

What are the symptoms of gestational diabetes?

Most women who are diagnosed with gestational diabetes have no symptoms.

But you might experience:

• fatigue
• thirst
• frequent urination.

These symptoms are common in pregnancy, so they don’t necessarily mean you have gestational diabetes.

How is gestational diabetes diagnosed?

Glucose tolerance test

This is one of the routine tests in pregnancy. This test is recommended at:

• 24-28 weeks of pregnancy if you don’t have type-1 or type-2 diabetes
• 10-16 weeks if you’ve had gestational diabetes before or you have an increased risk of getting it.

The glucose tolerance test involves not eating or drinking overnight. Your blood is tested in the morning, and then you drink 75 g of glucose in a sweet drink. You have your blood tested twice more – after 1 hour and after 2 hours. If you have high blood glucose levels on a glucose tolerance test, you’ll be diagnosed with gestational diabetes.

A glucose tolerance test isn’t recommended if you’ve had weight loss surgery. In this situation, your midwife or doctor will talk with you about your options.

HBA1c blood test

At your first antenatal appointment, your doctor or midwife will probably recommend you have this blood test if you have an increased risk of getting gestational diabetes.

This blood test checks for diabetes that was present before your pregnancy or soon after you became pregnant. It’s a single blood test that measures your average blood glucose levels over the last 2-3 months. If you have a high result from this test, your midwife or doctor might recommend you have your glucose tolerance test at around 10-14 weeks.

If you’re eligible for a Medicare card, Medicare almost always covers the cost of blood tests for gestational diabetes.

How is gestational diabetes managed?

If you have gestational diabetes, you’ll need extra support and care to make sure you have a healthy pregnancy. Your midwife or doctor will talk with you about how to manage your diabetes. It’s also a good idea to see a dietitian and a diabetes educator with expertise in gestational diabetes. And you might be referred to a specialist diabetes doctor.

Healthy eating, physical activity and healthy weight gain

Healthy eating is important for your health and your baby’s development. But what you need to eat to keep your blood glucose levels within a healthy range might be different from what’s usually recommended in pregnancy. So it’s important to talk with a dietitian about the best diet for you.

You might also need specialist advice about physical activity and healthy weight gain.

Blood glucose monitoring

Blood glucose monitoring shows the effect of food and physical activity on your blood glucose levels. This helps your doctor work out whether you need diabetes medicine.

To monitor your blood glucose, you prick your finger and place a small amount of blood onto a testing strip that you put into a blood glucose monitor. You usually do this 4 times a day – before eating or drinking in the morning and then 1 or 2 hours after each meal. A diabetes educator will help you work out the best testing routine.

Ask your doctor or diabetes educator whether you can get a blood glucose monitor and testing strips for free. You can also buy them at a pharmacy.

Insulin injections and other medicine

Sometimes you might change your diet and physical activity, but your blood glucose levels stay high. In this situation, your doctor might recommend insulin injections or a medicine called metformin, depending on your needs.

You’ll need to monitor your blood sugars and might need to see your doctor or midwife more frequently. You’ll also need advice from a diabetes educator about the balance between medicine, activity and nutrition.

Labour and birth care

Managing your diabetes during pregnancy will give you the best chance of having a positive, rewarding and safe birth experience. Your midwife or doctor will also probably recommend that you give birth in a public or private hospital or birth centre.

During labour your blood glucose levels will be monitored regularly.

After birth care

Your blood glucose levels will be monitored while you’re in hospital. It’s also recommended that they’re tested again 6-12 weeks after birth. An annual HBA1c blood test is also recommended.

Your baby’s blood glucose levels will be checked within 2 hours of birth.

Early skin-to-skin contact with your baby and frequent breastfeeding can stabilise your baby’s blood glucose levels. Breastfeeding for at least 9 months can also reduce the risk of your baby developing type-2 diabetes later in life, as well as your own risk of developing diabetes.

Testing and care in future pregnancies

If you’ve had gestational diabetes, you’re more likely to have it in future pregnancies. Talk to your health professional about early diabetes testing if you plan to get pregnant again.

If you have gestational diabetes, you can register with the National Diabetes Services Scheme and get diabetes products at lower prices. Your health professional can help you sign up to the scheme.

Can gestational diabetes be prevented?

You can’t always prevent gestational diabetes.

But there are things you can do to reduce your risk of developing gestational diabetes. These precautions can also reduce the severity of gestational diabetes if you do develop it:

• Tell your midwife or doctor about any family history of diabetes or gestational diabetes.
• Go to your antenatal appointments.
• Eat well. Make sure to include a wide range of vegetables and legumes, fruit, wholegrain cereals and grain foods, meat or meat alternatives, and dairy or dairy alternatives. Talk to your midwife, doctor or dietitian if you’re finding it hard to eat well.
• Aim for 30 minutes of physical activity a day. Light to moderate walking, swimming and stationary cycling are usually safe in pregnancy.
• Talk to your midwife or doctor about the healthy weight gain that’s recommended for you and how to achieve it.

Healthy eating, regular physical activity and weight management during and after pregnancy can reduce your future risk of type-2 diabetes. If you need support, talk to your midwife, doctor or child and family health nurse.