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Understanding the link between gestational diabetes and type 2 diabetes

What is gestational diabetes?

Diabetes is a condition where the amount of glucose in the blood is too high. Gestational Diabetes Mellitus (GDM) is a type of diabetes that occurs during pregnancy. It is diagnosed following a 2 hour Oral Glucose Tolerance Test (OGTT) at around 24 to 28 weeks of pregnancy. This is a blood test ordered by your GP, obstetrician or antenatal clinic. This is considered a ‘universal test’, which means all pregnant women should have this test.

If high blood glucose levels (BGLs) are not treated, a number of problems can develop in a pregnant woman or her baby. Women with poorly controlled BGLs are at much higher risk of developing type 2 diabetes mellitus (permanent diabetes) after pregnancy. This risk increases further when women do not follow a healthy lifestyle (including diet and exercise modifications) or are unable to lose their pregnancy weight.

What can I do during my pregnancy to reduce my risk of developing permanent diabetes?

All studies point to the benefits of ongoing contact and support from an expert maternal health dietitian when managing your GDM to help you follow the recommended diet and lifestyle. Studies testing the effectiveness of GDM nutrition guidelines have shown improved pregnancy outcomes (less need for insulin and better control of BGLs) when women saw a specialist maternal health/GDM dietitian a minimum of three times during their pregnancy.

What can I do after my pregnancy to reduce my risk of developing permanent diabetes?

The good news is that there is a lot that a woman can do to minimise her risk of developing type 2 diabetes. A woman’s risk of developing permanent diabetes is reduced dramatically by continuing a healthy lifestyle after pregnancy through breastfeeding, undertaking regular exercise, healthy eating and achieving and maintaining a healthy weight.

1. Follow up with your GP

It is recommended women who had GDM repeat the OGTT around 6 – 12 weeks after their baby arrives. Your GP can organise this test. This helps both the woman and her family doctor to plan for ongoing care of her health. If this test is normal, she should plan to have a repeat glucose screen (OGTT) every one to two years – about the time she has her Pap smear. Half the women who have had GDM may go on to develop type 2 diabetes later in life, so knowing sooner leads to better outcomes. Also, studies show that women who have had GDM are at increased risk of developing it again in future pregnancies.

2. Breastfeeding

There are many reasons ‘encouraging and supporting breastfeeding’ is one of the Australian Dietary Guidelines; one of them is the benefit to women following a pregnancy affected by GDM. Studies show that women are twice as likely to develop type 2 diabetes if they do not breastfeed, have a 15% decrease in their risk of type 2 diabetes each year they breastfeed, and women with the lowest risk are those who manage to breastfeed for at least 9 months. Breastfeeding offers a safe, feasible and low–cost intervention to reduce the risk of subsequent permanent diabetes.

3. Lifestyle changes - being physically active, losing weight, and eating a good quality/nutritious diet

The most successful intervention study to prevent type 2 diabetes to date was the American ‘Diabetes Prevention Program’. This study showed that making lifestyle changes was MORE effective than taking metformin (a tablet used to manage type 2 diabetes in some people) in preventing permanent diabetes. The goals set for women who took part in the lifestyle intervention program included targets around 1. The amount of weight to lose, 2. what she ate, and 3. how active she was. Even though this was delivered as part of a group support program there are some useful take-home messages from which everyone can benefit. They include:

  • Undertake moderate intensity physical activity for more than 150 minutes each week. What does this mean in practical terms? A good goal is at least half an hour of moderate-intensity physical activity on most, preferably, all days. You do not have to do it all at once. Your exercise can be spread over the day, in ten minute blocks. Try three ten minute walks, or two fifteen-minute periods of activity. What does moderate-intensity activity mean? Moderate-intensity means you are exercising at a comfortable pace. A good guideline is the “talk test”—you should be able to maintain a conversation easily without being short of breath.
  • Include at least 15g of fibre per 1000kcal of intake. What does this mean in practical terms? For most women this would be a fibre intake of around 25-30g each day. The best ways to increase fibre in your diet? As the dietary guidelines say, “Eat a wide variety of food every day” – include plenty of vegetables, fruit, and grain foods (preferably wholegrain).
  • Reduce total fat to less than 30% of your total energy (kilojoule or calorie) and saturated fat to less than 10% of your total energy intake. What does this mean in practical terms? This is as much about what to include in your daily diet, as much as what to limit. Be aware that foods high in saturated fats include: fatty meats, full fat dairy products, butter, two vegetable oils (coconut and palm oil), most deep fried take away foods, and most commercially baked products such as biscuits and pastries, including meat pies and sausage rolls. Instead, eat plenty of plant based foods. These are a good source of fibre, vitamins, and minerals and are low in saturated fat and salt. These include: breads and cereals, fruits and vegetables and legumes; lean meats, poultry, fish, reduced fat dairy products. And healthier fats (mono and polyunsaturated fats) instead of saturated fats.
  • Lose more than 5-7% of body weight, if above your most healthy weight. What does this mean in practical terms? For most women, this is a loss of only 4 to 5 kg. Further health benefits come from greater losses, and are enhanced by increasing physical activity. When working towards weight loss goals it is imperative to not only look at what you eat but also why you eat, how you eat and where you eat. One of the most common techniques Mater Health and Wellness dietitians use with clients is a range of strategies to help them identify their patterns of Non Hungry Eating.
  • Multiple contacts with a health professional (dietitian) for individualised counselling to support these lifestyle changes was also shown to enhance success.

Here at Mater Health and Wellness, specialist maternal health-GDM dietitians are able to tailor a program to support you to adapt guideline recommendations to your lifestyle and preferences. Please phone 07 3163 6000 to make an appointment with a Mater Health and Wellness dietitian to help you achieve your goals.


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