Gestational Diabetes

Gestational diabetes (GDM) is a type of diabetes that arises during pregnancy (usually in the second or third trimester).

GDM occurs because the body cannot produce enough insulin to meet the extra needs of pregnancy.

Approximately 3% of women develop diabetes during their pregnancy.

A test called an Oral Glucose Tolerance Test (OGTT) is used to diagnose GDM. This includes a blood test following an overnight fast then a repeat blood test two hours after a glucose drink. This test is offered up to 34 weeks gestation in York. After 34 weeks gestation we ask ladies to perform a weeks' worth of glucose testing and one of the diabetes team will review the data to establish if a diagnosis should be made.

Pregnant women who have certain risk factors including:

• Obesity

• Family history of diabetes

• Unexplained stillbirth or neonatal death in a previous pregnancy

• Large infant in a previous pregnancy (4.5kgs)

• If you have had GDM before

• Your family origin is South Asian, Black Caribbean or Middle Eastern.

Treating Gestational Diabetes

As with women with pre-existing diabetes, it is important to control the level of glucose in your blood during pregnancy. The targets are set to tight ranges to try and avoid complications such as too much fluid around the baby, large gestational age baby or pre-term labour. NICE recommends a fasting level below 5.3mmol/L and less than 7.8mmo/l one hour after eating.

Often blood glucose levels can be controlled by diet and exercise. You will be referred to a dietitian to advise you about healthy eating. If your blood glucose levels cannot be controlled by diet and exercise then you may need tablets or insulin injections to help keep your blood glucose within the target ranges.

After the birth

As soon as you have delivered your baby, you will be able to stop any treatment you were recommended to take during your pregnancy. This is because your glucose levels should return to normal once the placenta is delivered and the stress of pregnancy is resolved. 

You will be advised to test your glucose levels for 24 hours after delivery. These can range from 4.0-11.1mmol/L for this duration of time. 

In the future

If you have had GDM you are 90% more likely to develop gestational diabetes again in subsequent pregnancies and will be picked up in the process much earlier during your next pregnancy. 

To help guard against this eating a healthy diet and including some physical activity into your daily routine can help. The Department of Health recommends 5 x 30 minutes of moderate exercise per week. You should be able to say the words to a song but not sing them! 2 x 30 minutes of muscle strengthening is also recommended.

We recommend you see your GP between 13-24 weeks after delivery and annually thereafter for a diabetes blood test. Your GP can also refer you into the Healthier You Diabetes Prevention Programme.

The Healthier You programme is available both as a face-to-face group service and as a digital service. When referred into the programme, people are free to choose between the two.

People on the face-to-face group service receive personalised support to manage their weight, eat more healthily and be more physically active – which together have been proven to reduce a person’s risk of developing type 2 diabetes.

The digital service offers similar support but through the use of digital tools such as wearable technologies that monitor levels of exercise, apps where users can access health coaches, online peer support groups and the ability to set and monitor goals electronically.