Diabetes - gestational

Gestational diabetes is diabetes that occurs during pregnancy. After the baby is born blood glucose levels usually return to normal.

Diabetes is a common condition in which there is too much glucose in the blood. The pancreas either cannot make insulin and/or the insulin it does make cannot work properly to control the level of glucose in the blood. Insulin is a hormone that is needed to transport glucose from the blood stream into cells where it is needed for energy.

Between three and eight per cent of pregnant women will develop gestational diabetes. It is usually detected around weeks 24 to 28 of pregnancy though it can develop earlier. Being diagnosed with gestational diabetes can be both unexpected and upsetting. It can raise immediate questions such as – Will my baby be affected? Will I have diabetes for the rest of my life? What do I need to do to manage this condition?

Various health professionals are usually involved in helping you manage gestational diabetes. You will be given information about how to test and monitor blood glucose levels and, dietary advice with a dietitian. Working closely with your doctor and healthcare team can help you to lower your blood glucose levels and keep them within the normal range.

High risk groups

Certain women are at increased risk of developing gestational diabetes. High risk groups include:

• Women over 30 years of age
• Women with a family history of type 2 diabetes
• Women who are overweight or obese
• Indigenous Australians and Torres Strait Islanders
• Women of particular ethnic groups including Indian, Chinese, Vietnamese, Middle Eastern, Polynesian and Melanesian women
• Women who had gestational diabetes in a previous pregnancy.

How does gestational diabetes develop?

The placenta produces hormones that help the baby to grow and develop, but these hormones also impair the action of the mother’s insulin. This is called insulin resistance. As the pregnancy progresses, the mother’s energy needs increase and her insulin needs are also higher than normal. Some women are unable to produce extra insulin and blood glucose levels rise.

When the pregnancy is over and the need for insulin returns to normal, the diabetes usually disappears.

Effects on the baby

Glucose crosses the placenta, from mother to baby because it is required to meet the energy needs of the developing baby. If the mother’s blood glucose levels are raised, a greater amount of glucose will cross the placenta to the baby. To cope with this extra glucose the baby produces more insulin. This promotes excessive growth and fat in the baby.

If the mother’s blood glucose levels remain raised, the baby can be larger than normal. Following delivery, the baby may experience low blood glucose, particularly if the mother’s blood glucose levels were elevated before the birth. Gestational diabetes can be monitored and treated and if well controlled, these risks are greatly reduced. The baby will not be born with diabetes.

Symptoms

Gestational diabetes usually has no obvious symptoms. If symptoms occur, they can include:

• Unusual thirst
• Excessive urination
• Tiredness
• Thrush infections.

Diagnosis

Most women are diagnosed using a special test, which requires a blood sample to be taken after a glucose drink. These tests are usually performed at about week 24 into the pregnancy, or earlier if the woman is at high risk. There are two types of tests:

• Glucose challenge test (GCT) – blood is taken and the glucose level is measured one hour after the drink. If this is above normal, an oral glucose tolerance test is required.
• Oral glucose tolerance test (OGTT) – involves taking a blood sample after the woman has fasted overnight, a glucose drink is consumed and then a second blood sample is taken two hours later. A diagnosis is based on the results of the OGTT.

Treatment

Gestational diabetes is managed with:

• Diet – you are encouraged to eat a varied diet that is nutritionally appropriate for pregnancy, including foods rich in calcium, iron and folic acid. Your diet should be low in saturated fats and high in fibre. Carbohydrates such as grains, cereals, fruits, pasta and rice are an important part of your eating plan to provide you with energy and essential nutrients. You may need to discuss with a dietitian the amount and distribution of carbohydrate intake to assist in the control of your blood glucose levels.
• Physical activity – regular physical activity like walking helps to keep you fit and prepares you for the birth of your baby and will help to control your blood glucose levels. Check with your doctor before starting something new or particularly strenuous.
• Monitoring blood glucose levels – regular testing of your blood glucose levels is essential so that treatment can be assessed and changed as necessary. A diabetes nurse educator will teach you how this is done, when to test and the level of blood glucose to aim for.
• Insulin injections – may be needed to help control the glucose level in the normal range. Blood glucose lowering tablets are generally not used in pregnancy. Insulin is safe to take during pregnancy and does not cross the placenta from the mother into the baby.

Long-term outlook

After the baby is born, the mother’s blood glucose levels usually return to normal. A follow-up blood test (OGTT) is recommended six to eight weeks after the baby is born.

Women who have gestational diabetes have a high chance (almost one in two) of developing type 2 diabetes within 20 years. Type 2 diabetes can be prevented so it is important to take steps to reduce your risk. You should:
Maintain a healthy eating plan

• Maintain a healthy weight for your height
• Engage in regular physical activity
• Have a follow-up blood test (OGTT) every year.

Where to get help

• Your doctor
• Obstetrician
• Diabetes specialist or endocrinologist
• Diabetes educator – ask at the hospital where you are booked to have your baby or alternatively you may see a diabetes educator privately
• Diabetes Australia Victoria Tel. 13 RISK (13 7475)
• An accredited practising dietitian, contact the Dietitians Association of Australia

Things to remember

• Gestational diabetes is diabetes that occurs during pregnancy.
• When the pregnancy is over, the diabetes usually disappears.
• Women who develop gestational diabetes have an increased risk of developing type 2 diabetes.
• A healthy lifestyle is important for both mother and baby to reduce risk of diabetes in the future.

You might also be interested in:

• Diabetes.
  
• Diabetes - diagnostic tests.
  
• Diabetes and healthy eating.
  
• Diabetes and kidney failure.
  

Want to know more?

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This page has been produced in consultation with and approved by:

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Diabetes Australia Victoria

Last reviewed: February 2011

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<a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Gestational_diabetes?open">Diabetes - gestational - Better Health Channel</a><br/>
Gestational diabetes occurs during pregnancy. When gestational diabetes is well controlled, the risks to the baby and mother are greatly reduced. Women are at greater risk of developing type 2 diabetes after experiencing gestational diabetes. Gestational diabetes is diagnosed using an oral glucose tolerance test (OGTT).

Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your qualified health professional. Content has been prepared for Victorian residence and wider Australian audiences, and was accurate at the time of publication. Readers should note that over time currency and completeness of the information may change. All users are urged to always seek advice from a qualified health care professional for diagnosis and answers to their medical questions.

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