Diabetes is a condition in which there is too much glucose (sugar) in the blood. The rise in glucose occurs because the body can't make enough insulin or the insulin produced is not working properly. Insulin is a hormone produced by the pancreas that moves glucose from the blood stream, into the cells of the body where it is used for energy (see 'Living with Type 2 Diabetes' fact sheet for more information).

What is gestational diabetes?

Gestational diabetes refers to diabetes that develops during pregnancy and usually goes away after the baby is born. It typically occurs after the 26th week of pregnancy when the pancreas may be unable to produce or release enough insulin to keep blood glucose levels in the normal range.

During pregnancy, there are many hormonal changes that occur, which can affect insulin levels and insulin action. As the baby and placenta grow during pregnancy, the body may be unable to sufficiently adapt to the changing hormone levels to maintain normal blood glucose levels. Therefore, about one in ten women in Australia develops gestational diabetes and this rate is steadily increasing. Gestational diabetes usually disappears after the birth of the baby. However, women who have gestational diabetes are prone to developing type 2 diabetes.

Who is at risk?

If you are pregnant and any of the following apply to you, you should consult your general practitioner or obstetritian to discuss your risk of gestational diabetes:

• over 30 years of age
• previously had gestational diabetes
• have a family history of type 2 diabetes or gestational diabetes
• overweight or obese
• from an Indigenous Australian or Torres Strait Islander background
• from a Pacific Islander, Indian Subcontinent, or Asian background
• have polycystic ovary syndrome (PCOS)

"I didn't think I was at risk because I was only a little bit overweight" (Molly, 29)

Who should be tested?

Currently it is recommended that all women are screened for gestational diabetes between 24 and 28 weeks of pregnancy. Women at very high risk should be screened earlier. The most commonly used screening test is a glucose challenge test. If this test is positive a more detailed test, an oral glucose tolerance test, is done. This will help your doctor identify if your body is able to maintain normal blood glucose levels during your pregnancy.

If you do develop gestational diabetes it is vital that you repeat the oral glucose tolerance test 6 to 8 weeks after the birth of your baby, to check if blood glucose levels have returned to normal.

How is gestational diabetes managed?

For many women, being diagnosed with gestational diabetes can be distressing so it is important that you see a diabetes health professional for better understanding and assistance in managing the condition. The main aim of management is to keep blood glucose levels within the normal range. This will require regular monitoring of blood glucose levels, a healthy eating plan and regular physical activity. Blood glucose levels can usually be managed with lifestyle changes, but sometimes insulin injections may be needed.

"Has made me more aware that I need to look after my diet more as I am high risk to develop type 2 diabetes. I felt a bit disappointed that I got it with the second pregnancy as well and not able to enjoy the food I would like. I feel a bit restricted..." (Kim-Ly, 34)

What does it mean for my baby if I have gestational diabetes?

If undetected or inadequately treated, it can lead to problems for you and your baby. Your baby may be large when born, making delivery difficult. The baby might also be born with low blood glucose levels and may need to spend some time in a special care nursery. Other complications include an increased risk of a premature birth and even miscarriage.

"My sister had gestational diabetes during her final pregnancy and her baby had to be induced prematurely, which really motivated me to get fit and healthy before and during my pregnancy so that I didn't put my baby at risk" (Jo, 30)

When gestational diabetes is managed well, the above risks are greatly reduced.

How can I avoid developing gestational diabetes?

If you have any of the mentioned risk factors, it is important to prepare for a healthy pregnancy prior to becoming pregnant. You can do this by controlling weight, being physically active and adopting a healthy eating plan. This will reduce your risk of gestational diabetes. Whilst pregnant, it is also important to optimise a healthy lifestyle by following recommendations on healthy weight gain and engaging in regular physical activity.

What does it mean for my future health?

Women who have had gestational diabetes are at risk of developing type 2 diabetes. It is estimated that approximately 35-60 per cent of women with gestational diabetes will develop type 2 diabetes within 10 years of childbirth. It is recommended that women with a history of gestational diabetes are screened for diabetes at least every two years.

To prevent or reduce your risk of developing type 2 diabetes, it is important to:

• Maintain a healthy weight
  Keep your weight within a healthy weight range. Ideally for women, your waist measurement should be less than 80cm. If you are overweight, it is important to reduce your weight before pregnancy. If you need assistance with this, speak to your general practitioner.
• Adopt a healthy eating plan
  Eat plenty of fruit and vegetables, drink six to eight glasses of water per day (1.5-2 litres), eat one to three serves of fish each week, and eat low-fat high calcium foods and wholegrain foods daily. Make sure to limit your alcohol intake, butter and animal fats, takeaway foods, energy dense snack foods and sweetened drinks such as soft drink (See 'Healthy Eating for You' fact sheet for more information).

"At first I was upset as I thought I would require injections every day and I would have a large baby, now I believe I have eaten much better than I otherwise would have throughout my pregnancy, which has benefits for me and the baby." (Amina, 31)

• Engage in regular physical activity
  Be active every day in as many ways as you can. Aim for at least 30 minutes of moderate-intensity physical activity on most, preferably all, days (see 'Physical Activity' fact sheet for more information).

It is vitally important for all women with a history of gestational diabetes to continue to have a follow-up at least every two years with your doctor and appropriate screening tests to assess your risk of type 2 diabetes, as symptoms may not always be obvious and can go unnoticed.

Where can I find more information?

www.jeanhailes.org.au
www.healthforwomen.org.au
www.diabetesaustralia.com.au – Diabetes Australia: 1300 136 588
www.adips.org – The Australasian Diabetes in Pregnancy Society 

Content updated February 2012