Gestational diabetes mellitus (GDM) is a diagnosis made by your obstetrician or endocrinologist when your blood glucose levels are higher than normal during the pregnancy. This occurs between 3 to 8% of pregnant women, and generally develops between the 24th and the 28th week of pregnancy. Sometimes gestational diabetes may occur earlier in the pregnancy.
When a woman is pregnant, their body requires two to three times more insulin than when she is not pregnant. Gestational diabetes occurs when the body is not able to produce this increased insulin, leading to higher glucose levels than normal, as the action of insulin in the body is to reduce glucose levels.
Problems can arise in the pregnancy if gestational diabetes is not diagnosed and managed properly. It can lead to problems with the baby’s growth (usually leading to big babies, but sometimes there can also be growth restriction, leading to small babies), and the risk of stillbirth is increased in mismanaged or undiagnosed gestational diabetes.
The biggest risk factor for developing gestational diabetes is a past history of the condition in a previous pregnancy.
Other risk factors for Gestational diabetes include:
Gestational diabetes is also more common in women of the following ethnicity:
Gestational diabetes is best managed in a multi-disciplinary team, involving the obstetrician, diabetes educator, dietitian, endocrinologist and the GP. Dr Ken Law will lead this multi-disciplinary team to optimally manage your gestational diabetes.
Monitoring the blood glucose levels during the pregnancy is vital to ensuring that optimal outcomes are achieved in the pregnancy. This usually involves checking the blood glucose levels 4 times per day – before breakfast, and then 2 hours after the commencement of each meal.
The targets for blood glucose levels are:
These targets for blood glucose levels are much stricter than the targets that people with type 2 diabetes aim for. This is because stricter glycaemic control has been shown to result in better outcomes for women and babies in gestational diabetes.
Healthy exercise and adopting a healthy eating pattern are essential to optimising blood glucose levels. If such lifestyle modifications are not enough to achieve good glycaemic control, then further medical intervention may be required. This may involve the use of oral medications (e.g. Metformin), and some women may need to use insulin injections during the pregnancy to better control the glucose levels.
The body’s digestive system breaks down Carbohydrate foods into glucose, and this glucose is then used for energy. Carbohydrates are very important for you and your growing baby. However it is important to spread your carbohydrate foods over 3 small meals and 2 to 3 snacks per day, in order to help manage the blood glucose levels.
The following foods are rich in carbohydrate:
It is best to avoid carbohydrate foods that contain little nutritional value. These include:
In some instances, women with gestational diabetes may already be eating the right amount and type of carbohydrate foods for their body, but still have high blood glucose levels. In this situation, it is important not to cut back on carbohydrates, and medications such as Metformin or insulin injections may be considered.
It is important to try to limit the amount of fat you eat, particularly saturated fat, and this is even more important in women with gestational diabetes. For cooking, use healthy fats such as canola, olive and polyunsaturated oils, and margarines, avocados and unsalted nuts.
The overall aim is to reduce your intake of saturated fat. Choose lean meats, skinless chicken and low fat dairy foods. Avoid takeaway and processed foods.
While fat does not directly affect your blood glucose levels, all fats can cause extra weight gain, especially if eaten in large amounts. This will ultimately make it more difficult to control blood glucose levels.
As protein is important for the growth and maintenance of the body, and the growing fetus, try to include 2 small serves of protein per day. Foods rich in protein include:
These foods do not affect your blood glucose levels directly.
While milk, yoghurts, custards and legumes are important sources of protein, it is important to remember that they also contain carbohydrate.
During pregnancy, calcium and iron requirements are increased. It is recommended that pregnant women should include 3 serves of low fat, calcium-rich foods each day.
Examples of one serve of calcium-rich foods include:
The iron from red meat, chicken and fish is well absorbed by the body. However, vegetarians and women who do not eat these foods regularly may need iron supplementation or may need to take pregnancy multi-vitamins.
The overall aim in pregnancy is to eat nutritious foods that will not cause excess weight gain or cause the blood glucose levels to go up. These foods include:
A healthy balanced diet should include at least 5 serves of vegetables per day.
In pregnancy, it is important to remember to continue to avoid those foods that are at risk for Listeria.
Women who have a family history of food allergies or intolerances should seek advice from their obstetrician or dietitian, as it may be advisable to avoid certain foods during pregnancy.
Choose mainly water, plain mineral water and soda water. For some variety, try adding some fresh lemon or lime. Soft drinks and other sweet drinks should be minimised.
All alternative sweeteners available in Australia have been thoroughly tested and approved by Food Standards Australia and New Zealand (FSANZ). These are generally considered safe to eat.
After the birth of the baby, the woman’s glucose level generally improves. However women who have had gestational diabetes are at an increased risk of developing type 2 diabetes, with up to 50% chance of developing diabetes within 20 years of a gestational diabetes pregnancy. Therefore it is recommended that women who have had gestational diabetes have screening tests performed on a regular basis to look for type 2 diabetes in the long-term.