Gestational diabetes (GDM) is a condition in pregnancy where there is a higher than normal blood glucose level in the mother. This is thought to be due to higher than normal levels of a hormone called Human Placental Lactogen from the placenta. The vast majority of GDM is detected at 28 weeks of pregnancy, but can occur later.
GDM is diagnosed by a Glucose Tolerance Test.
Women who are at higher risk for developing GDM include:
- Those who have a family history of Type 2 Diabetes
- Older mothers
- Those with 2 or more previous pregnancies
- Those who are overweight
- Women who have an Aboriginal or Torres Strait Islander background
- Women who have a South East Asian, Middle Eastern, Melanesian or Polynesian background
- Those who have had GDM in previous pregnancies
Once the diagnosis of gestational diabetes (GDM) has been made, it is time to commence glucose monitoring. The aim is to maintain fairly tight control of your blood sugar levels (a Blood Sugar Level between 3.5 – 7.5).
Initially, you will check your blood sugar level just before each main meal (lowest level) and 2 hours after each main meal (peak level). You will also commence a diabetic diet which is organised through a dietician (nutritionist).
- If your sugars are well controlled by diet alone, there is no increased risk to the baby, above that of a normal pregnancy.
- If your sugars are not well controlled, then you may need to see an Endocrinologist if you need insulin. Alternatively your obstetrician may start you on a tablet called Metformin which is safe in pregnancy. The need for Insulin indicates that your diabetes is more significant and there are some increased risks to you and the baby.
If insulin is required to manage the blood glucose levels, induction of labour or caesarean section (emergency or elective) will generally be required before term. For GDM controlled with diet and exercise only, the pregnancy can usually be safely taken up to 41 weeks to await spontaneous labour, with consideration of induction of labour around this time.
If you follow the correct diet and your sugars are not well controlled – it is not your fault. The hormones in pregnancy are to blame and you have no control over this.
Some of the potential problems which can occur in the mother are:
- Polyhydramnios, extra fluid around the baby. This can lead to premature breaking of the waters and premature labour.
- Difficult delivery of a large baby.
- Increased risk of diabetes later in life in both you and the baby.
Some of the potential problems which can occur in the baby are:
- Macrosomia, a big fat baby with broad shoulders.
- Difficult delivery, the shoulders can get stuck. This is an emergency.
- Jaundice after delivery.
- Low blood sugar levels in the baby after delivery, requiring intravenous glucose solution.
This is not meant to be a complete list but should alert you to the fact that this can be a serious condition.
After delivery, the baby will need close monitoring of its own blood glucose levels, as these can fall after delivery up until when the mother’s milk comes in, which usually occurs late day 3 after delivery. The baby may need admission to the nursery during this time, and some added feeds with formula for the first few days of life until the mother’s milk supply is adequate.