Gestational diabetes: why you're at risk

If you’re pregnant, you may be at risk of developing gestational diabetes. Here’s what every pregnant mum needs to know.


Insulin is a hormone which controls blood glucose levels. During pregnancy, insulin requirements double, if not quadruple. This is due to the insulin needs of the baby, and because other hormones produced during pregnancy can block how well insulin works in the mother’s own body. Gestational diabetes develops when a mother cannot produce enough insulin to meet these needs. It typically develops after week 24 of pregnancy.

Thankfully gestational diabetes can often be managed through diet and exercise alone, and it differs from type 1 and 2 diabetes in that it usually resolves after delivery. Some women will require medication or insulin to control their blood glucose. A baby born to a mother with gestational diabetes will not have diabetes when it is born, and keeping blood sugars well controlled during pregnancy can reduce the risk of your baby developing diabetes or obesity later in life.

When we eat a meal, our body breaks down carbohydrates into glucose. The glucose then moves into our bloodstream to be either used by muscles, stored or converted to fat. Insulin is the hormone that helps us to move this glucose out of the blood and into our cells. If we do not have adequate insulin, the level of glucose in our blood increases and this can be harmful to mother and baby. Therefore close monitoring and support from a variety of health professionals is important.


As glucose is the fuel source for the brain, regular supply is important for both mother and baby so glucose must not be totally avoided. To keep blood glucose levels within the recommended range however, it is important to work with a dietitian to alter carbohydrate quantities, types and timing.

The Glycaemic Index (GI) is a rating of carbohydrate-rich foods according to how quickly they affect blood glucose levels after eating them. Foods are categorised as having a low, moderate or high GI. Low GI carbohydrates are more complex for the body to digest, and typically provide more fibre than high GI carbohydrates. Because of the increased effort required to break them down, the glucose is released more slowly into the blood, allowing more time for insulin to control glucose levels. These are a great carbohydrate source for people with any type of diabetes. Examples of low GI foods are legumes, wholegrain breads, wholegrain crackers and basmati or brown rice.

Moderating carbohydrate portions within each meal, and spreading carbohydrate intake over the whole day can help to allow time for blood glucose to be used or stored, before it is hit with the next load. Carbohydrate intake should be spread over three meals, plus two snacks over the day. It is very important to avoid high sugar foods that provide no nutritional benefit, such as sugary drinks, lollies, cakes and biscuits.

When reading labels, try to remember that 4g = 1tsp of sugar! 


There is conflicting information as to whether fat intake should be reduced; however, the most important thing is to ensure foods consumed are low in saturated fat. Choose fats from healthy sources such as nuts, olive oil, avocado, and seeds.


Exercise is incredibly beneficial, as not only does it help with weight management and mental health, it also improves how well the mother’s body responds to insulin, and how well glucose is taken into the muscles. Regular moderate-level exercise over the week is ideal, and even just 10 to 15 minutes of exercise within an hour of a meal can help control blood glucose. Try doing housework, bathing the kids or going for walk to keep moving. Women who are not exercising prior to pregnancy or have any complications should discuss exercise with their doctor/midwife.


Following gestational diabetes, the risk of developing type 2 diabetes later in life is increased by 50-60%, therefore annual testing is required. Women should ensure a healthy diet and exercise are maintained, and that body weight does not increase post pregnancy as this increases the risk.

Healthy eating and exercise can be hard when you’re tired and pregnant or when there’s a new baby in the house, so look at what support systems you can put in place; meet a friend for a walk instead of a coffee and muffin; cook twice the amount and freeze portions; use a slow cooker; try to plan meals in advance.



  • ½ cup of wholegrain oats made into porridge, cooked using trim/calci-trim milk and served with sliced fruit and 2 Tbsp of yoghurt
  • 2 scrambled eggs on 1 slice of wholegrain toast

Morning Tea

  • Apple and 10 almonds


  • 2 Slices of wholegrain bread, canned tuna and plenty of salad
  • 1 Cup of brown rice with canned salmon, cherry tomatoes and cucumber
  • 150g tub of yoghurt

Afternoon Tea

  • 2 Wholegrain crackers with 30-40g edam cheese
  • Carrot sticks


  • 100-120g chicken breast
  • closed-fist sized portion of kumara
  • plenty of vegetables


  • Over 30 years of age
  • High body mass index
  • Close family history of type 2 diabetes (parents or siblings)
  • Previous stillbirths or miscarriages
  • Previous babies with high birth weight (greater than 4kg)
  • Maori, Pacific Island, Chinese or Indian ethnicity

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