Gestational diabetes

Cases of gestational diabetes (also known as pregnancy diabetes or diabetes in pregnancy) are on the rise, putting pregnant women and their unborn babies at serious risk.

Between 2013 and 2018, the number of women diagnosed with gestational diabetes increased from 22,215 per year to 40,823 per year (112 new cases every day in 2018).*1,2

*as registered with the National Diabetes Services Scheme


Graph adapted from National Diabetes Services Scheme data1,2

This pattern coincides with an increase in expectant mothers who are older, who are overweight/obese or whose ethnic background puts them at high risk.

What is gestational diabetes?

Gestational diabetes refers to diabetes that first occurs, or is first recognised, during pregnancy.

Hormonal changes due to being pregnant can make your body lose its ability to control the levels of sugar (glucose) in your blood. Uncontrolled blood sugar levels during pregnancy may then lead to a range of health issues for you and your baby.

What causes gestational diabetes?

Your body normally keeps the level of sugar in the blood at a specific level. The hormone insulin is responsible for moving sugar out of your blood and into your muscles and liver, where it can be used as energy.

Unfortunately, the hormones responsible for supporting your pregnancy and the development of your baby make your body resistant to insulin. As your pregnancy progresses, more and more insulin is required to keep your blood sugar at the right level. Most, but not all, women can meet the increased demand for insulin – those who can’t develop gestational diabetes.

What are the symptoms of gestational diabetes?

Almost all women with gestational diabetes have no symptoms. This is why testing is highly recommended for all pregnant woman, not just those who are at high risk.

However, when symptoms occur, some of the more obvious ones include:

  • Increased need to urinate
  • Extreme fatigue
  • Excessive thirst/dry mouth
  • Nausea
  • Yeast (thrush) infections
  • Blurred vision.

As you can see, distinguishing the signs of gestational diabetes from that of a normal pregnancy can be difficult. However, symptoms are usually more severe with gestational diabetes. It’s a good idea to have your diabetes risk assessed early in your pregnancy and follow up with regular reviews by your obstetrician.

Who is at risk of developing gestational diabetes?

We know that various factors may increase your risk, such as a previous history of gestational diabetes, carrying excess weight and older age.

Risk factors

  • Age above 35
  • Being overweight or obese
  • Previous history of gestational diabetes
  • Family history of type 2 diabetes
  • Previous baby weighing over 4.5kg
  • Aboriginal, Torres Strait Islander, Asian, Polynesian, Middle Eastern or Indian ethnicity
  • Excessive weight gain during pregnancy
  • Antipsychotic or steroidal medication
  • Polycystic ovary syndrome (PCOS)

What are the dangers of gestational diabetes?

With early detection and management of gestational diabetes, we would still usually expect a healthy and uneventful pregnancy.

However, if gestational diabetes is left undetected or poorly managed, the following issues can occur:

  • Increased risk of shoulder dystocia during birth (the baby’s head delivers but its shoulders become stuck) – this results from excessive foetal girth and can cause trauma for baby (bone fractures, nerve damage) and mother (vaginal tearing)
  • Increased risk of pre-term delivery
  • Respiratory distress or low blood sugar for your baby, requiring admission to a special-care nursery
  • Pre-eclampsia (high blood pressure, fluid retention and protein in the urine)
  • 1 in 2 risk that you will develop type 2 diabetes later in life
  • Increased chance of your child developing type 2 diabetes later in life.

How is gestational diabetes diagnosed?

The oral glucose tolerance test (OGTT) is the standard test used to diagnose gestational diabetes.

For an average-risk pregnancy, testing is typically performed between 26 and 28 weeks (when gestational diabetes is likely to develop).

If you have a history of gestational diabetes or are considered high risk, testing and management may begin at an earlier stage in your pregnancy.

The OGTT involves:

  • A fasting blood sample in the morning
  • Consuming a concentrated sugary drink
  • Taking blood samples 1 and 2 hours later.

A diagnosis of gestational diabetes is made if your blood sugar level is above the normal range at any point during the testing.

How is gestational diabetes treated?

If you are diagnosed with gestational diabetes, we can often manage it effectively throughout your pregnancy with lifestyle modifications. Timely intervention allows most women to continue on with a normal pregnancy and reduces the chance of complications, such as those listed above.

Managing gestational diabetes

  • Consume a healthy, balanced diet – avoid foods that are high in sugar or processed carbohydrates.
  • Exercise regularly at a level suitable for you
  • Attend all review appointments with your obstetrician, diabetes educator and endocrinologist (if required)

Implementing these changes is usually enough to effectively control blood sugar levels, although medication may be required for some women. More frequent appointments are required to monitor your progress and the condition of your baby.

Depending on the severity of your gestational diabetes, delivery is usually recommended between 38 and 40 weeks. It is generally not advisable to go past your due date.

Once you have given birth, the diabetes will often resolve. However, there is a 50% chance that you may develop type 2 diabetes later so remember to maintain a healthy diet, healthy weight and regular exercise.

Can I prevent gestational diabetes?

Prevention is difficult because many of the causes are out of your control, such as your family history and the hormone levels produced by your placenta.

However, there are also controllable risk factors – namely, high pre-pregnancy weight and excessive weight gain during pregnancy. The best way to manage these is by consuming a diet low in sugar and processed carbohydrates.

Read more about healthy weight gain in pregnancy and pre-pregnancy health

Do you need a specialist opinion?

Early detection and management are essential when it comes to gestational diabetes. If you have any concerns prior to or during your pregnancy, don’t hesitate to call my rooms on (03) 9418 8299 or book an appointment online.



1. National Diabetes Service Scheme: Gestational Diabetes as at 31 December 2018 (accessed online 16 January 2019). Available at

2. National Diabetes Service Scheme: Gestational Diabetes at 31 December 2013 (accessed online 16 January 2019). Available at


The information on this page is general in nature. All medical and surgical procedures have potential benefits and risks. Consult a healthcare professional for medical advice specific to you.


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