What is Gestational Diabetes?

Gestational diabetes refers to diabetes that is first recognised in pregnancy. It is usually a temporary form of diabetes. It typically goes when the baby is born and the placenta is delivered.

How common is gestational diabetes?

In Australia, 18 000 women develop gestational diabetes each year.
Around 5 – 9% of all pregnancies are affected. The risk of developing gestational diabetes is higher in particular ethnic populations.

Gestational diabetes is generally diagnosed between the 24th to 28th week of pregnancy.

Diabetes is a condition in which the level of glucose in the blood is too high.

• Glucose normally enters the bloodstream after eating foods containing carbohydrates.
• Insulin is a hormone that helps transport glucose from the bloodstream into the body's cells. It is produced by the pancreas.
• Diabetes occurs when glucose is not effectively moving from the bloodstream into the cells. Blood glucose levels become elevated.

What happens in pregnancy?

In pregnancy, the placenta produces hormones that support the growth and development of the baby. These hormones also impair the action of the mother's insulin. This is known as insulin resistance. During pregnancy women need to produce 2–3 times the usual amount of insulin to overcome this resistance. If the body is unable to produce the extra insulin required or it becomes more resistant, gestational diabetes develops.

Around 5 – 9% of all pregnancies are affected. The risk of developing gestational diabetes is higher in particular ethnic populations.

Who is most at risk of developing gestational diabetes?

Women most at risk of developing gestational diabetes:

• Are over the age of thirty
• Are overweight or obese
• Are from particular ethnic backgrounds: Vietnamese, Chinese, Middle-Eastern, Polynesian, Indian, Mediterranean
• Are Aboriginal or Torres Strait islanders
• Have a family history of type 2 diabetes
• Have had gestational diabetes in past pregnancies
• Have previously had a baby weighing over 4kg
• Have Polycystic Ovary Syndrome (PCOS)

However, as many women who develop GDM do not have identifiable risk factors, it is recommended all women be screened between 24 to 28 weeks gestation.