Gestational diabetes is a type of diabetes that occurs during pregnancy. Diabetes is a common condition whereby the blood glucose levels become difficult to control. Insulin is a hormone produced by our bodies to help control blood sugars. The condition usually resolves once the baby is born.

Development of gestational diabetes
During pregnancy, hormones are made by the placenta to help the baby develop and grow. These hormones, however, stop the mother’s insulin from working properly. This is called insulin resistance. As the pregnancy develops and the baby grows bigger, the mother’s body has to make more insulin to keep her blood glucose at normal levels.

Later in pregnancy the amount of insulin needed to keep blood glucose levels normal is two to three times higher than usual. If the body is unable to produce enough insulin to keep blood glucose levels in the normal range, gestational diabetes develops.

Women at risk of gestational diabetes
About 9 per cent of pregnant women develop gestational diabetes. It is usually detected around weeks 24 to 28 of pregnancy, although it can develop earlier. Being diagnosed with gestational diabetes can be both unexpected and upsetting. A glucose tolerance test (GTT) is used to diagnose the condition. It involves fasting overnight, then blood is taken before a glucose drink and then one hour and two hours after the drink.

Certain women are at increased risk of developing gestational diabetes. This includes women who:

  • are over 30 years of age
  • have a family history of type 2 diabetes
  • are overweight or obese
  • are of Aboriginal and Torres Strait Islander descent
  • are of particular cultural groups, such as Indian, Chinese, Vietnamese, Middle Eastern, Polynesian and Melanesian
  • have previously had gestational diabetes
  • take some antipsychotic or steroid medications
  • have previously had a baby whose birth weight was greater than 4,500 grams (4.5 kg)
  • have had a previous complicated pregnancy.
  • have had polycystic ovarian syndrome.

Many women who develop gestational diabetes have no known risk factors.


  • Education about diabetes
  • Healthy diet
  • Physical activity
  • Blood glucose monitoring
  • Oral tablets – Metformin
  • Insulin injections

Usually your blood glucose levels return to normal quite quickly after the baby’s birth. Another GTT is done six to eight weeks post- natal to ensure the diabetes has gone away.