Gestational Diabetes

Gestational diabetes occurs when a pregnant woman has high levels of glucose in her blood. High blood glucose is caused because the mother can’t produce enough insulin (a pregnant woman’s insulin needs are two to three times that of normal).

There are two reasons why the mother needs more insulin:

  • Because pregnancy causes certain types of hormones (that are made by the placenta) to be released. These hormones make it harder for insulin to do its job
  • Because the growth demands of the foetus (developing baby) increases the mother's need for insulin

Unlike type 1 and type 2 diabetes, gestational diabetes is only temporary and usually disappears after pregnancy. However, a woman who has had gestational diabetes has an increased risk (50-60%) of developing type 2 diabetes in the future; therefore they should be tested for type 2 diabetes each year.

Why insulin is important

Insulin is a natural hormone produced by the body. It is needed to take the sugar from your blood and move it into your cells (where it is used as an energy source for the various things that cells have to do). If your body cannot make enough insulin, sugars from the foods you eat will stay in your blood stream and cause high blood sugars. High blood sugar levels are known as hyperglycaemia.

What can gestational diabetes do to me and my child?

The risks to you include:

  • An increased chance of needing a caesarean section to deliver your baby
  • An increased chance of developing HOP (toxaemia or pregnancy induced hypertension and protein in the urine)
  • An increased chance of getting urinary tract infections

The risks to your baby include:

  • Being very fat and large at birth. Babies who are too large or fat at birth have a much higher risk of developing serious problems following their birth
  • Having their shoulders dislocated during the birth process (because they are too large to fit well through the birth canal)
  • Having a serious low blood glucose level soon after birth. This can happen because before being born your baby had been getting a very high level of glucose out of your blood (across the placenta). The baby had adjusted to this high glucose level by making high levels of it's own insulin. When the placenta separates after birth this high level of glucose (from you) suddenly stops. The baby still has very high levels of it's own insulin and this can cause it's blood glucose to fall too low.
  • Prolonged new-born jaundice
  • Low levels of calcium in its blood
  • Respiratory distress syndrome (this can be quite dangerous)

Am I at risk of developing gestational diabetes?

If you have one or more of the following factors you are more likely to develop gestational diabetes:

  • Having a family history of type 2 diabetes in a close relative (parents or brothers and sisters)
  • Having gestational diabetes in a previous pregnancy
  • If a previous baby had a birth defect
  • If you are very overweight
  • If you are aged over 30
  • If you have had a previous stillbirth or spontaneous miscarriage
  • If you’ve had a previous large baby (greater than 4 kilos )
  • If you have a history of pregnancy-induced high blood pressure, urinary tract infections, or polyhydramnious (too much amniotic fluid)

What can be done about gestational diabetes?

In most cases, gestational diabetes is able to be managed by diet and exercise during the pregnancy. It usually disappears after the baby is born once the need for high levels of insulin (during pregnancy) has gone.

Some women with gestational diabetes require insulin to manage their blood sugar levels in a healthy range during the pregnancy. If you do need insulin, it will help to keep both you and your baby healthy during the pregnancy.

It is very much better for both you and your baby to be in the care of a specialist team if you have been diagnosed with gestational diabetes. This team can help you to learn the skills you need to know to manage your gestational diabetes.

You will most probably want to talk over each of the following issues with your health care team members:

  • Keeping your blood glucose levels in a healthy range.
  • Using a home blood glucose meter to test your blood glucose levels. Whether you need to do this testing and if so how often, will depend on the results of your laboratory blood glucose levels.
  • Managing your weight gain during pregnancy. But remember that good nutrition is important during pregnancy. A dietician will help you work out your nutritional needs.
  • A healthy level of exercise (exercise helps improve blood glucose levels for some people, and is important to improve flexibility and prepare you for childbirth)
  • Breastfeeding. There isn’t any reason why you shouldn’t breastfeed baby. Your milk is the best source of food for your baby.

Remember, if you have had gestational diabetes you should be checked for type 2 diabetes every year for the rest of your life. Your best defence against developing type 2 diabetes is to try to keep your body weight lean and get plenty of physical exercise. Some women remember this by 'staying lean and mean'.

Find out how a New Zealander managed her gestational diabetes - Marice Pouesi: Wanting a healthy future for her grandchildren