Gestational Diabetes


What is this?

Pregnancy changes the way the body processes carbohydrates, in order to make glucose available for the needs of the baby. The placenta releases substances which cause a resistance to insulin, resulting in blood glucose levels which remain higher, for longer, after meals. Usually this means more insulin is produced, but in some non-diabetic women, the pancreas is not able to meet these extra demands, causing them to develop signs of diabetes in pregnancy.

How is it diagnosed?

At your booking appointment, the midwife will ask questions about your medical history and that of your family to see if you have any risk factors for diabetes. If so, you will be referred for a glucose tolerance test [see below].

Also, your urine will be checked for the presence of glucose at each antenatal appointment. In pregnancy, changes in kidney function make glycosuria [glucose in the urine] more likely, especially if you have been eating something sweet! This does not necessarily indicate gestational diabetes, but if it is detected on two or more occasions, you will also be referred for a glucose tolerance test.

What is a glucose tolerance test?

This involves having a fasting blood test, carried out early in the morning, to measure the glucose levels in your blood when you havent eaten for at least 8 hours. You are then given a carefully measured, very sweet drink, which contains a specific amount of glucose.

You will have another blood test about 2 hours later, to measure the increased glucose levels. It is important that in the intervening 2 hours you dont have anything to eat or drink [except water] as it would affect the results.

The results of both your tests are compared with the blood glucose levels which are considered to be normal for your stage of pregnancy. If your results exceed these limits, you will be referred to the diabetes specialist nurse, who will work out a plan of care to ensure that your blood glucose levels are well-controlled throughout the rest of your pregnancy.

Will I have to inject insulin?

It depends. Sometimes gestational diabetes is very mild, and can be managed by diet alone, just by eating those foods which help to keep your blood glucose levels stable. If the diabetes does need to be controlled by insulin injections, you will be taught how to do this safely and given plenty of time to discuss any concerns you might have.

You will have regular appointments with the diabetes team to monitor how effectively your condition is being controlled, and to adjust the doses of insulin accordingly. There will also be a plan drawn up for your labour.

Once you are in established labour, you often dont feel like eating, so at regular intervals your blood glucose will be monitored, to ensure it stays at a safe level. You may need to be started on a sliding scale intravenous infusion of insulin and glucose, to maintain this level. This will be stopped as soon as your baby is born.

Will my baby have diabetes too?

In the uterus, your baby is subjected to the same blood glucose levels found in your blood. If your diabetes is poorly controlled and there is a large amount of glucose, the baby has to respond by producing more insulin. This can accelerate the babys production of fat and muscle, leading to increased birthweight, even in premature babies.

You will have regular ultrasound scans to estimate your babys weight. If the baby is thought to be excessively large, your labour may have to be induced early, or it may be recommended that you have a caesarean section. After the birth, your baby will continue to produce this extra insulin initially, but without the high levels of glucose he has been used to in the uterus.

Even with frequent, regular feeding, he may find it hard to maintain his blood glucose levels initially and these will need to be monitored very carefully. Sometimes babies need to be admitted to the Special Care Baby Unit for the first 24 hours or so, so their blood glucose can be stabilised and maintained at a safe level.

Will I remain diabetic?

This can sometimes happen, but in the vast majority of women, gestational diabetes resolves quickly after the birth. Your insulin will be stopped straight away, and your diabetes nurse will tell you how often you need to monitor your blood glucose levels. You will be reviewed again about 3 months after the birth. However, if you have another baby, you may develop the problem again.