Gestational

Gestational diabetes is a form of diabetes that occurs during pregnancy. It usually goes away after the baby is born

Around 18% of pregnant women will develop gestational diabetes.

Gestational diabetes (sometimes referred to as GDM) is diagnosed when higher than normal blood glucose levels first appear during pregnancy.

This usually occurs around the 24th to 28th week of pregnancy.

Gestational diabetes indicates an increased risk of developing type 2 diabetes in the future.

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

Gestational diabetes can happen to anyone. Certain factors can increase a woman’s risk, including:

• over the age of forty
• are overweight or obese
• are from particular ethnic backgrounds: Vietnamese, Chinese, Middle-Eastern, Polynesian, Indian, Mediterranean
• are Aboriginal or Torres Strait Islander
• 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. If your blood glucose is above a certain level at any of these points you will be diagnosed with gestational diabetes.

How is gestational diabetes managed?

There are some increased risks for you and your baby when you have gestational diabetes. This includes increased risk of high blood pressure during pregnancy, having a larger baby, or your baby having low blood glucose levels at birth.

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. A healthy lifestyle can help to reduce the risk of type 2 diabetes for you and your baby.

Pregnancy health checks

Your diabetes and maternity health care team will monitor you and your baby throughout your pregnancy. They will monitor your weight, blood pressure, the baby’s growth and development and additional blood tests as needed.

You will monitor your blood glucose levels at home at different times of the day and discuss these results with your diabetes health professional. This will help guide your management plan to keep your glucose levels within the target range for a healthy pregnancy.

Labour and birth

Most women with gestational diabetes will have a pregnancy that progresses normally and without complication. Most women will be able to deliver vaginally and close to their due date. If your baby grows too large or there are any other concerns your maternity team may suggest an induction to start labour one or two weeks early.

As with all women, there is a possibility that you may need a caesarean delivery. This may be required if your baby is large or for other reasons such as a low placenta, the baby being in a breech position, or if you’ve had a previous caesarean.

Speak with your maternity team about the possibility of induction or caesarean delivery so you can be well prepared if it happens.

Once labour starts its important to keep your blood glucose levels in the target range. This will help to prevent your baby’s blood glucose levels dropping too low after delivery. When you are in labour the maternity team will look after your diabetes management.

After your baby is born

The midwife, obstetrician or paediatrician will check your baby including their heart rate, colour, breathing and blood glucose level. They will check your baby’s blood glucose level by doing a heel prick. This is to check if your baby’s glucose levels have dropped too low after birth. It does not mean your baby has diabetes. If the glucose level is low, your baby may require some extra feeds or some glucose. Talk to your midwife about using your breastmilk for additional feeds if possible. Your midwife will regularly check your baby’s glucose level until it is within the normal range.

Breastfeeding

Having gestational diabetes does not affect your choice whether to breastfeed or not.

Breastfeeding has many benefits for you and your baby, including:

• supporting your baby’s immune system
• helping you bond with your baby
• reducing the risk of type 2 diabetes for you and your baby

For breastfeeding information and support, speak with your midwife or lactation consultant, or call the National Breastfeeding Helpline on 1800 686 268

Your health post pregnancy

Once your baby is born your glucose levels will usually go back to normal, now that the hormones from the placenta are no longer causing insulin resistance. If you were using medications or insulin to manage gestational diabetes these will normally be stopped.

Your diabetes health professional will let you know how often to check your blood glucose levels. You will be advised to have another oral glucose tolerance test 6-12 weeks after your baby is born. This is to make sure your blood glucose levels have returned to the healthy range.

Although diabetes goes away for most women following pregnancy, there is an increased risk of developing pre-diabetes or type 2 diabetes. There is also an increased risk of developing gestational diabetes in future pregnancies.

It can be a challenging period as you adjust to life with a newborn, but some simple tips will help to keep you and your family healthy.

• Aim to have regular diabetes checks every 1-3 years depending on your risk factors for type 2 diabetes. This can be done as part of routine blood tests with your GP.
• Aim to be in the healthy weight range. It will take some time to return to your pre-pregnancy weight. A good goal is to aim to reach this within 6-12 months after your baby is born.
• Include a variety of healthy foods. Read more on food and nutrition.
• Include physical activity each day. Read more on ways to be physically active.