Gestational Diabetes

Gestational diabetes only occurs in pregnancy

Gestational diabetes can occur at any stage of pregnancy, but is more common in the second half. It occurs when your body can't produce enough extra insulin to meet the demands of pregnancy. Gestational diabetes should go away after you've given birth. Approximately 700,000 women give birth in England and Wales each year, and up to 5% of these women have either pre-existing diabetes or gestational diabetes.*

Preventing gestational diabetes

Women should try to achieve a healthy weight before conception as active weight reduction during pregnancy is not appropriate because of the risk of compromising maternal and foetal health.

Physical activity may have the potential for preventing Gestational Diabetes and related adverse health outcomes.

Try aiming for 30 minutes of moderate activity. Physical activity has been known for its role in improving glucose homeostasis through its direct or indirect impact in insulin sensitivity.

It is important to know that you're twice as likely to develop Type 2 diabetes later in life if you have gestational diabetes when you're pregnant.

If you develop gestational diabetes

• You are more likely to develop gestational diabetes if you’re overweight; with a BMI (body mass index) above 30
• Have given birth to a large baby, weighing more than 4.5kg (9.9lb), in the past
• You’ve had gestational diabetes before
• You have a parent, brother, sister or grandparent with diabetes
• Your origin is south Asian, black Caribbean or Middle Eastern

If you're in any of these higher risk categories, you should be offered a test to check for gestational diabetes. You may be given a home testing kit to check your blood glucose levels, or you may be offered an oral glucose tolerance test at 28 weeks or earlier.

If you're diagnosed with gestational diabetes, you're at risk of having a large baby, which increases the risk of a difficult delivery, having your labour induced or a caesarean section delivery.

Conditions affecting the woman

• Urinary tract infections
  These infections are most common when a woman has gestational diabetes. They are caused by bacteria which grow more easily when blood glucose is high.
   
• Caesarean section
  This procedure is more common in women with gestational diabetes.
   
• Pre-eclampsia
  This is a condition that has three main symptoms: high blood pressure, protein in the urine and swelling of various parts of the body (this swelling is called oedema by doctors).
   
• Polyhydramnios
  This is the condition of having too much amniotic fluid (amniotic fluid is the liquid inside the uterus). The uterus is where the baby grows and develops. Polyhydramnios can cause the baby to be born early.

Conditions affecting the baby

• Macrosomia
  This means 'large baby'. If your blood glucose rises too high, then the extra glucose will affect your baby. The baby will make extra insulin to compensate for the extra glucose, and the combined effect is to make the baby grow bigger and faster than it should. A large baby can be hard to deliver.
   
• Hypoglycaemia of the baby
  If the baby is exposed to high glucose levels, it will produce more insulin to balance them out. After the baby is born, the high level of insulin will overwhelm the amount of glucose that it gets from milk, and so its blood glucose level will be too low.
   
• Jaundice
  Jaundice makes a newborn baby's skin look yellow. This is more common if the mother has gestational diabetes. It is caused because the baby has to break down blood cells after it is born, and the breakdown product is yellow (all babies have to do this). If the baby's liver is immature at birth, the skin can become yellowish.

There are a few rarer conditions that are associated with gestational diabetes, but they are less common than the ones listed here.

Although the list on these pages may be frightening, it is worth remembering that good control of your blood glucose and following the instructions of your healthcare team will reduce the risk and allow you to have a healthy baby.

Managing your blood glucose during pregnancy

Keeping your blood glucose well controlled has many benefits, including:

• Reducing the risk during pregnancy
  All of the problems caused by gestational diabetes on the previous two pages are reduced by good control of blood glucose.
   
• Avoiding severe hypos
  Hypos occur when your blood glucose falls too low. It is difficult to avoid hypoglycaemia completely when your diabetes is treated with insulin and, if your everyday blood glucose is fairly low, hypos may seem more of a risk.
  
  Many people, however, find that it is the big swings in blood glucose, from very high to very low, which may lead to severe hypoglycaemia. When their blood glucose is well controlled they may feel mildly hypo slightly more often, but severe hypos are rarer.
  
  Hyperglycaemia occurs when you let your glucose get too high and it isn't good for you anymore than low blood glucose is, and letting your glucose get very high may lead to a risk of diabetic coma. Keeping an eye on your blood glucose is the best way to avoid both hypo and hyper glycaemia.
   
• Feeling better today
  If you keep your blood glucose well controlled you may find that you feel fitter and have more energy. With pregnancy, energy levels can often fluctuate anyway, which is all the more reason to control your blood glucose levels.

After the birth

Your blood glucose level should return to normal soon after the birth. Your doctor or nurse will organise checks to ensure that this happens. After you have had gestational diabetes your risk of diabetes later in life is increased.

*Statistics have been taken from NICE Guidelines [NG3]: Diabetes in pregnancy: management of diabetes and its complications from preconception to the postnatal period. Published February 2015. Available at https://www.nice.org.uk/guidance/ (Last accessed April 2015).