Diabetes in pregnancy
diabetes; pregnancy; gestational; insulin; glucose; sugar; fetus; blood; testing; urine; tolerance;
Contents
Diabetes (diabetes mellitus) is a condition where the body cannot get enough energy from food because there is not enough insulin. Insulin is a hormone produced in the pancreas, which helps glucose go from the blood stream into the body's cells. It controls the levels of glucose (sugar) in blood.
Most of the information in this topic is about gestational diabetes, which is diabetes that develops during pregnancy. Some of the information is also relevant for women who have diabetes before they become pregnant.
For more information about diabetes causes, complications and management see the topics 'Diabetes - about diabetes' and 'Diabetes - living with diabetes'.
Pregnancy and type 1 and 2 diabetes
If you already have either type 1 or type 2 diabetes when you become pregnant you need to continue with your normal routines.
- Good management of blood glucose levels is especially important during pregnancy and you will need to monitor your blood glucose more often.
- It is particularly important during pregnancy to eat healthily and to exercise regularly.
- Careful management of diabetes through healthy eating and exercise will help to prevent complications.
- It is best to plan your pregnancy, so that your diabetes is well controlled before you become pregnant, but if your pregnancy is unplanned, careful control during the pregnancy will still help protect your baby and yourself.
- See the doctor who normally helps you manage your diabetes as soon as you know you are pregnant.
- Aim to check your blood glucose levels four or more times a day and record them. Also record exercise, what you eat, any stressful events and the effects of these on your blood glucose.
- Good blood glucose control will mean that your baby will receive normal concentrations of glucose through the placenta and will grow and develop normally (your baby will not be stimulated to produce too much insulin which can cause problems for the baby).
What is gestational diabetes?
Gestational diabetes is a type of diabetes that develops during pregnancy and affects up to 5% of pregnant women. It generally occurs around the middle of the pregnancy (after about 24 weeks). Gestational diabetes usually goes away after pregnancy. However, women who have had gestational diabetes are more likely to develop diabetes in later life. It is important for them to be tested regularly for diabetes later in life.
What causes gestational diabetes?
- Your body needs more energy than usual during pregnancy so more insulin is required to move glucose into the cells to provide energy.
- The placenta also produces other hormones during pregnancy and some of these hormones can block the action of insulin in your body and cause 'insulin resistance' to develop. Much more insulin is needed to do the same amount of 'work'.
- This happens for all women during pregnancy, but for some, the pancreas is not able to produce enough insulin for the body's needs, so high levels of glucose remain in the blood stream and this is called gestational diabetes.
- It usually takes many weeks before the amount of insulin that the pancreas makes is not enough, so gestational diabetes does not appear until the middle of pregnancy.
Glucose in blood is measured in millimoles per litre (mmol/L) and the normal range is from 3 to 7 mmol/L. Levels higher than this may indicate diabetes.
Who
develops gestational diabetes?
Some people are more likely to develop gestational diabetes than others. You are more likely to develop gestational diabetes if:
- you are overweight
- you have a family history of diabetes
- you are over 30 years old
- you have had 'large' babies (over 4000g), miscarriages or unexplained still births in the past.
How is
gestational diabetes found?
During pregnancy most women have urine or blood tests 'routinely', and these may show higher levels of glucose than usual. If high levels are found, or there are other reasons to think that diabetes may be present, extra tests will be done to be sure this is diabetes.
- Testing for gestational diabetes is usually done between the 26th and 28th week of pregnancy. First you will have a glucose challenge test and if the results are above normal it will be followed up by a glucose tolerance test.
- A glucose challenge test takes 1 hour. You will be asked to drink a glucose solution and an hour later a simple blood test will measure the amount of glucose in your blood using a blood glucose meter.
- A glucose tolerance test takes 2 hours. You will be required to fast (no food) from the night before the test. A blood sample will be taken and you will then be given a stronger glucose solution to drink. You will be asked not to smoke, eat or drink anything except some water. Another blood sample will be taken 2 hours later. If the amount of glucose in the blood rises above a certain level gestational diabetes is diagnosed.
How is
gestational diabetes treated?
There is not yet any 'cure' for diabetes but blood glucose levels can be controlled and kept within a healthy range. This is usually done by healthy eating and exercise, but insulin injections are needed by some women. The major health centres usually have diabetes educators and dietitians available to help you manage your diabetes. They will also teach you how to test and record blood glucose levels and some can lend or hire out blood glucose meters.
For more information about management of diabetes, see the topic 'Diabetes - managing diabetes in childhood'.
Is a special diet needed?
No. The diet recommended for diabetes is a normal healthy diet, with regular meals. Measuring 'portions' is not needed.
Will insulin be needed?
In a few cases women with gestational diabetes will need insulin in addition to diet and exercise. Studies indicate that insulin in the mother's blood does not cross the human placenta and will not harm your baby. Because gestational diabetes goes away after pregnancy you will not need insulin afterwards.
How might
gestational diabetes affect the baby?
Your baby will not be born with diabetes, and most women who have gestational diabetes give birth to healthy babies, especially when their blood glucose has been well controlled and they have maintained a healthy weight.
Some problems which may occur as a result of gestational diabetes:
- The baby can be large at birth, generally with a birth weight over 4000g, due to too much glucose (but not all women who have big babies have diabetes.)
- Very large babies sometimes need to be delivered by caesarean section.
- A baby which is born big because of diabetes may lose a lot of weight in the first few days, but the baby's growth will then be normal.
- Breathing problems can occur, especially if the baby is premature (born early). The baby may need to be in a special care nursery and have oxygen or other help with breathing.
- Jaundice - a yellow colouring of the skin and eyes - can occur because the baby's liver is not mature enough (it happens mostly for premature babies). It usually disappears after a few days but some babies need treatment by being put under special lights.
- Low blood glucose (hypoglycaemia) can occur during the first couple of days of life. The baby may need to start breastfeeding (or formula feeding if that is the mother's choice) straight away to get extra glucose into the baby. Sometimes babies need to be given extra glucose by injection. Babies born to women who have diabetes will usually have their blood glucose checked regularly for a couple of days.
- Gestational diabetes does not cause your baby to have diabetes, but your child will be more likely than other people to develop type 2 diabetes as an adult (there is an inherited risk). Eating a healthy diet, exercising regularly and having a healthy weight may reduce that risk.
- Very big babies at birth (when a mother has gestational diabetes) are more likely to become overweight as children and adults. Again, a healthy diet and exercise may help reduce the risk of this. Being overweight as children or adults increases the risk of developing type 2 diabetes.
- Fully breastfeeding your baby during the first 6 months of life may reduce the risk of your baby becoming overweight during childhood.
Gestational diabetes usually does not cause birth defects or deformities because women with gestational diabetes usually have normal blood glucose levels during the first trimester (first 3 months) which is when the baby's body systems are developing.
Can
diabetes cause problems in pregnancy?
Most women with gestational diabetes can safely have a full term pregnancy and have a normal labour, but there may be problems due to the diabetes.
- Pregnancy induced hypertension (PIH) - high blood pressure caused by pregnancy is fairly common in all pregnancies, but is more common when a mother has diabetes. It usually goes away soon after the birth of the baby. (It was previously called pre-eclampsia.) If the mother's blood pressure becomes too high the baby will need to be delievered early (prematurely).
- Infections, such as bladder infections are also fairly common during pregnancy, but are more common when the mother has diabetes
- If the mother's blood sugar is not well controlled during the pregnancy there is an increased risk of miscarriage or still birth.
If a woman who has diabetes also smokes during the pregnancy, there is a greater risk of problems for both the mother and the baby.
Resources and references
The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Youth Healthline on 1300 13 17 19 (local call cost from anywhere in South Australia).