Newly Diagnosed

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.

Just diagnosed? Here’s how we can help.

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Talk to one of our health professionals by calling 1300 198 204.

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Your Baby

After delivery, your baby’s blood glucose levels will be checked.

Your baby’s blood glucose level will be assessed by taking a pinprick test from the heel after birth and at regular intervals for the first day or so.

Also, routine observations such as heart rate and breathing will be checked regularly.

Usually your baby is able to remain with you.

In some situations, for example, if there are problems maintaining the baby’s blood glucose levels, your baby may be monitored and cared for in the nursery.


Breastfeeding has many beneficial effects for the newborn baby.

Breastfeeding soon after the birth will help to maintain your baby’s blood glucose levels. Breast milk contains antibodies which help protect your baby against particular illnesses, infections and allergies.

An added bonus to the mother is that breastfeeding can assist with weight control.

Research has found that women who breastfeed may reduce their risk of developing type 2 diabetes later in life.

Important fact: You having gestational diabetes does not cause your baby to be born with diabetes.

However, your baby may have an increased risk of developing type 2 diabetes later in life.

The Birth

Most women with gestational diabetes will have a pregnancy that progresses normally and without complication.

Most women with gestational diabetes are able to have a normal vaginal delivery – but are more likely to have a caesarean section than women without gestational diabetes.

Most women with gestational diabetes have a perfectly normal birth and healthy baby.

But it is important to take extra care.

During labour, your baby’s heart beat will be monitored closely, as will your blood glucose levels (particularly if you were treated with insulin).

In situations where treatment has involved high doses of insulin, an insulin and glucose infusion (also known as a drip) may be required.

Labour may also be induced earlier than the due date if concerns with the pregnancy arise. For example, if the baby grows too large.

A delivery plan will be discussed with you closer to your delivery date.

Within days after delivery of your baby, your blood glucose levels will usually return to normal.

Your healthcare team will advise you how often to monitor your blood glucose. When your levels have returned to normal (between 4mmol/L to 8 mmol/L) monitoring is no longer required.

If you were treated with insulin this will be stopped when your baby is born.

Antenatal Care

Antenatal care aims to monitor the health of both mother and baby.

Women with gestational diabetes may need special tests in addition to routine antenatal care.

Some of these tests may include:

An ultrasound

An ultrasound checks on the baby’s growth and development.

Later in pregnancy it is used to help estimate foetal weight, locate the placenta and assess the amount of amniotic fluid.

A biophysical profile is an ultrasound that checks the breathing, movements and muscle tone of the foetus, as well as the amount of amniotic fluid. This provides detailed information about the baby’s health.

Foetal heart rate

Foetal heart rate monitoring is conducted with a CTG (cardiotocograph) scan. 

The monitor is placed on the mother’s abdomen to measure the baby’s heart beat.

Kick chart

A Kick Chart is a record of how often you feel your baby move.

You may be asked to keep a record of your baby’s movements late in the pregnancy. A healthy baby tends to move the same amount each day.

You will be instructed to contact your doctor or midwife if the baby is not active.