Gestational diabetes

May 30, 2018

Gestational Diabetes (GDM) is a form of diabetes that occurs during pregnancy. If you have gestational diabetes your sugar levels are too high which affects you and also your unborn baby.It occurs in approximately 5 to 10% of all pregnant women and generally goes away once the baby is born.


During pregnancy placental hormones are secreted through a woman’s body. Thesenot only support the pregnancy but also help the baby develop.
These hormones block the action of insulin, a condition called insulin resistance. As a result the pancreas is required to secrete increasing amounts of insulin. However, if your body is unable to do this, then sugar levels increase and gestationaldiabetes develops.


You have an increased risk of developing gestational diabetes if you:

  • have a family history of Type 2 Diabetes
  • have an increased BMI
  • are an indigenous Australian
  • are from one of the these ethnic groups: Vietnamese, Chinese, Middle Eastern, Polynesian or Melanesian
  • have a past history of gestational diabetes
  • have a family history of gestational diabetes
  • have polycystic ovarian syndrome
  • have previously given birth to a large baby

There are generally no symptoms with gestational diabetes. As a result, at 26-28 weeks of your pregnancy, Iwill organise an oral glucose tolerance test (OGTT); this requires you to fast overnight and have a blood test prior to having a sugary drink. Following this initial test, further blood is taken one and two hours after you’ve had the drink.


If you have been diagnosed with gestational diabetes, I will generally see you more frequently throughout the pregnancy. This will be to ensure that your blood pressure is maintained within a normal range and to undertake ultrasound scans for the baby’s growth.

Part of your monitoring includes self-measuringof your blood sugar levels first thing in the morning and two hours after meals.

Initially, sugar levels will be controlled with a range of conservative measures such as diet and exercise. Often this will require a dedicated approach with advice from a diabetic educator and dietician.

Sometimes a woman’s blood sugar level is unable to be controlled utilising these methods and she will require insulin injections for the remainder of her pregnancy.

Once you have given birth to your child gestational diabetes generally disappears so you will be able to stop taking insulin. You will have a sugar drink test six weeks after you have given birth to determine whether your blood sugar levels have returned to normal.

Women who develop gestational diabetes have an increased chance of developing Type 2 diabetes later in life.


Women who have gestational diabetes have a 40% chance of developing Type 2 diabetes later in life.
Of course you are able to prevent this occurring by doing the following;

  • Maintaining a healthy eating plan
  • Maintaining a healthy weight range
  • Exercising regularly
  • Having regular follow-ups with your local doctor to ensure your blood sugar levels are normal.

Blood sugar levels are high in both mother and baby; as a result the baby’s pancreas will grow in order to make extra insulin. The extra sugar in the baby’s blood is stored as fat.

If untreated and uncontrolled gestational diabetes can lead to the following problems in babies:

  • Babies being born larger than normal which may result in a difficult vaginal birth and you may require a caesarean section
  • Sugar from the mother crosses the placenta and enters the baby’s blood. As a result the baby’s pancreas increases insulin production. Immediately after the birth the baby will no longer be in a sugar rich environment. In addition the baby will not be eating that much. Despite this their insulin levels remain high. This will result in low blood sugar so the baby may require extra support in order to maintain healthy insulin levels.
  • Babies can suffer from respiratory distress syndrome, a condition causing breathing problems
  • An increased chance of jaundice; where the whites of the eyes and skin turn yellow.

Babies who have a nutrient environment in the womb that is rich of sugar have an increased chance of being overweight and developing cardiovascular disease and diabetes when they are adults.

After birth your baby will require a heel prick test to take a small sample of blood to determine their sugar level. This is to ensure the baby’s sugar levels are in the healthy range and the baby doesn’t have low blood sugar levels. Ultimately the baby will be required to be fed as soon as possible after birth to regulate and maintain a good blood sugar level.


Gestational diabetes increases the chances of;

  • High blood pressure during pregnancy and secretion of protein in urine leading to a condition known as pre-eclampsia.
  • Oftenassociated with depression
  • An increased chance of requiring an assisted vaginal birth or a caesarean section

If you have previously been diagnosed with gestational diabetes, there is an increased chance of it reoccurring in future pregnancies. As a result I will arrange for an OGTT earlier in your next pregnancy. This is often done within the first 20 weeks, with a subsequent screen between 26 and 28 weeks if the initial screen was negative.


Further information about your gestational diabetes can be obtained from your local doctor, obstetrician, diabetes specialist endocrinologist, or a diabetes educator.

Diabetes Infoline telephone number:1300 136588.

Dr Joseph Sgroi is a member of the Women’s Health Committee of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists. He is a fertility specialist and obstetrician based at Melbourne IVF and Epworth Freemasons Hospital.

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