Gestational diabetes occurs during pregnancy and usually goes away after the baby is born.
Around 10% of pregnant women will develop gestational diabetes.
Gestational diabetes (sometimes referred to as GDM) is diagnosed when higher than normal blood glucose levels appear during pregnancy.
It is usually detected around the 24th to 28th week of pregnancy.
How does gestational diabetes occur?
In pregnancy the placenta makes hormones that support the growth of the baby.
These hormones also impair the action of the mother’s insulin. This is known as insulin resistance.
A mother’s body needs 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 to insulin, gestational diabetes develops.
If you are pregnant and have been diagnosed with gestational diabetes, it is important you have careful monitoring and management.
As glucose crosses the placenta to your growing baby, your baby will also have high blood glucose levels. As a mother’s insulin does not cross the placenta, your baby will need to make its own insulin. This can make your baby grow larger more quickly and can cause complications at birth.
Women at risk of gestational diabetes
Women most at risk of gestational diabetes include:
- 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 Iafeslanders
- have a family history of type 2 diabetes
- have previously had gestational diabetes
- have previously had a baby weighing over 4,500 grams (4.5 kg)
- take antipsychotic or steroid medications
- have Polycystic Ovary Syndrome (PCOS)
How is gestational diabetes diagnosed?
All women should be routinely tested for gestational diabetes around the 26th or 28th week of their pregnancy. In some cases (for example, if you are at high risk of developing gestational diabetes) the test may be done earlier.
The test is an Oral Glucose Tolerance Test (OGTT). You will be asked to fast overnight, and then a blood sample is collected in the morning. Following this you will then be asked to drink a glucose containing fluid. At one and two hours after this, further blood samples are collected. Your doctor will then review your results.
How is gestational diabetes managed?
Gestational diabetes is managed through eating a healthy diet, maintaining physical activity and monitoring of your blood glucose levels. Oral medication and/or insulin injections may be needed to lower your blood glucose levels to within a normal range.
After your baby is born, blood glucose levels usually return to normal. However, there is an increased risk for you developing type 2 diabetes in the future. Your baby may also be at risk of developing type 2 diabetes later in life.
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