nuhahyearlyLaunch pricing - Get £50 off!nuhahyearlyThe GTT is a screening test for gestational diabetes offered between 24 and 28 weeks if you have risk factors. You fast overnight, drink a glucose solution, then have blood taken after two hours. A fasting level of 5.6 mmol/L or above, or a two-hour level of 7.8 mmol/L or above, indicates gestational diabetes.
Gestational diabetes is a type of diabetes that develops during pregnancy in people who did not have diabetes before. It happens when your body cannot produce enough insulin to manage the extra demands of pregnancy. It affects roughly 4 to 5 in every 100 pregnancies in the UK.
In most cases, gestational diabetes is manageable with dietary changes and monitoring. Some people need medication or insulin injections. It usually resolves after birth, though it does increase your risk of developing type 2 diabetes later in life.
The NHS offers the GTT if you have one or more risk factors. These include a BMI of 30 or above at booking, a previous baby weighing 4.5kg (10lb) or more, gestational diabetes in a previous pregnancy, a parent or sibling with diabetes, or your family origin is South Asian, Black Caribbean, or Middle Eastern (populations with higher rates of type 2 diabetes).
If you had gestational diabetes in a previous pregnancy, you may be offered self-monitoring of blood glucose or an early GTT rather than waiting until 24 to 28 weeks.
If you do not have any of these risk factors, you will not routinely be offered the test. However, if glucose is found in your urine at a routine antenatal appointment, your midwife may arrange one.
The GTT requires you to fast overnight. You will be asked not to eat or drink anything other than water from around 10pm the night before. Most hospitals schedule the test first thing in the morning to make the fasting period manageable.
You can drink water freely. Bring something to eat for afterwards, as well as something to keep you occupied during the wait, such as a book or your phone charger. The test takes around two hours in total, and most of that time is spent sitting and waiting.
When you arrive, a blood sample is taken from your arm. This is your fasting blood glucose level.
You are then given a glucose drink containing 75g of glucose dissolved in water. It tastes very sweet, similar to flat lemonade. Most people find it manageable, though some feel nauseous afterwards. Sipping it slowly over a few minutes rather than gulping it can help.
After finishing the drink, you wait for two hours. During this time you need to remain at the hospital and avoid eating, drinking anything other than water, or doing strenuous activity. A second blood sample is then taken to measure how your body has processed the glucose.
Your results are usually available within a few days. Some hospitals can give you preliminary results on the same day.
Your results are compared against two thresholds set by NICE guidelines.
Fasting glucose. A level of 5.6 mmol/L or above indicates gestational diabetes.
Two-hour glucose. A level of 7.8 mmol/L or above indicates gestational diabetes.
If either value is at or above the threshold, you will be diagnosed with gestational diabetes and referred to a specialist diabetes in pregnancy team for support and management.
If both values are below the thresholds, the result is normal and no further action is needed.
A gestational diabetes diagnosis can feel worrying, but it is one of the most manageable pregnancy complications. You will be supported by a specialist team that typically includes a diabetes midwife, a dietitian, and an obstetrician.
Your management plan will usually start with dietary changes and blood glucose monitoring. You will be shown how to test your blood sugar levels at home using a finger-prick monitor, and a dietitian will help you adjust your meals to keep your levels stable. For many people, this is enough to manage the condition effectively.
If diet alone does not control your blood sugar, medication (usually metformin) or insulin injections may be recommended. Your team will support you with this and monitor you closely.
You will have additional scans to check your baby's growth, as gestational diabetes can cause babies to grow larger than average. Your care team will also discuss the timing and type of delivery with you, as induction or planned caesarean may be recommended depending on your individual situation.
Your blood glucose levels will be checked shortly after delivery and again at your 6-week postnatal check. Most people find that their blood sugar returns to normal once the baby is born.
However, having gestational diabetes means you have a higher chance of developing type 2 diabetes in the future. An annual HbA1c blood test is recommended to keep an eye on your glucose levels. Maintaining a healthy diet and staying active after pregnancy can significantly reduce this risk.
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