What is Gestational Diabetes?


In Australia more than 35,000 women develop gestational diabetes every year. Gestational diabetes is associated with an increased risk of complications in pregnancy and birth as well as a greater likelihood of mother and child developing type 2 diabetes later in life.  However, with good management these risks are significantly reduced.

Gestational diabetes is a condition that develops during pregnancy. The placenta produces hormones that help the baby grow and develop.  However, these hormones also block the action of the mother’s insulin.  This is referred to as insulin resistance.  Because of this insulin resistance the need for insulin in pregnancy is 2 – 3 times higher than normal.  If the body is unable to produce this much insulin gestational diabetes develops.  After your baby is born and your body’s insulin needs return to normal the diabetes usually disappears.

Those at risk of gestational diabetes include:

  • Older women, especially over 40 years of age
  • Women with a family history of type 2 diabetes or a first degree relative (mother or sister who as had gestational diabetes)
  • Women who are above the healthy weight range
  • Women who have had gestational diabetes in a previous pregnancy
  • Women who have had large babies (weigh more than 4.5kg)
  • Women who have a past history of polycystic ovary syndrome
  • Women who are taking certain types of antipsychotic or steroid medications
  • Women with certain ethnic backgrounds including Polynesian, Chinese, South East Asian, Middle Eastern or Indian.

Gestational diabetes is diagnosed after a glucose tolerance test. Once diagnosed, it needs to be treated because if a mother’s blood glucose levels are high, glucose passes through the placenta to the baby.  This may lead to a baby with a larger birth weight and this in turn can potentially cause more problems for both the mother and child during and following birth.  Untreated gestational diabetes can also lead to a greater likelihood of developing high blood pressure during pregnancy.

Once diagnosed with gestational diabetes we will refer you to a diabetic educator who will discuss with you the need to make changes in what you eat, particularly your carbohydrate intake and also teach you how to check your blood sugar levels. Following a healthy eating plan will assist you in managing your blood glucose levels within the target range advised by myself and the diabetic educator, as well as providing adequate nutrition for you and your growing baby.  Our main goal for treatment for gestational diabetes is to reduce the risk that the baby will be large.  This is more likely to occur if your blood sugar levels remain higher than normal.   I will liaise with the diabetic educator to ensure your blood sugar levels are on target.

Approximately 15% of women with gestational diabetes will require insulin.

Maintaining daily physical activity should also be part of your treatment plan. This can include walking and swimming.  It is important before starting or continuing any form of physical activity you should always check with your doctor.  Being inactive and gaining too much weight during your pregnancy will make it harder for you to manage your diabetes and the birth.  During your pregnancy you will be more closely monitored and therefore require more frequent ante-natal visits.  The purpose of these visits is to monitor you and your baby’s health.  After 34 weeks’ gestation I will see you twice a week and you will have fetal monitoring, or a CTG, performed to monitor the baby’s well-being.

If your blood sugar levels remain close to normal during the pregnancy and you have no other medical complications, the ideal time to deliver your baby is around the 39 week mark of your pregnancy.

After delivery most women with gestational diabetes have normal blood sugar levels and do not require any further treatment. I will however, organise for your blood sugar to be checked three months after the birth of your baby.  This is organised when you come and see me for your post-natal checkup at six weeks post-delivery.  Following delivery your baby’s blood sugars will also get tested and I recommend all women with gestational diabetes have their baby checked by a paediatrician.  This will be organised once you are in hospital.

Once you have had gestational diabetes you are at higher risk of developing diabetes later in life. Approximately 50% of women who have had gestational diabetes will develop type 2 diabetes within 10 to 20 years.  If you have another pregnancy there is a very high chance of developing gestational diabetes again.  Eating well and being active can reduce your risk of developing type 2 diabetes.

Depending on your risk factors you should also be checked by your GP for type 2 diabetes every one to three years. We understand that for many women being diagnosed with gestational diabetes can come as a shock and be upsetting.  However, with good management and a team effort including myself, the diabetic educator and the midwives in my practice, you can help keep your blood glucose levels within the normal target range.  This will provide the best outcome for you and your baby.