# Gestational diabetes: the sugar test and what it means > Common, very manageable, and nothing you did wrong Category: Pregnancy & postpartum · 5 min read · Written by the Splash team · Sources checked October 2026 URL: https://splash.care/learn/pregnancy-postpartum/gestational-diabetes ## Quick answer - Gestational diabetes is common and very manageable. - The sugar test (OGTT) is usually at 24 to 28 weeks if you have a risk factor. - Food, activity and sometimes medicine keep your levels in range. - Get a diabetes check 6 to 13 weeks after birth, then every year. [Gestational diabetes](https://splash.care/learn/glossary/gestational-diabetes) is high blood sugar that starts in [pregnancy](https://splash.care/learn/fertility-ttc/early-pregnancy-signs). It happens when your body cannot make enough insulin for the extra needs of pregnancy. It is not caused by eating too many sweets, and most people who have it go on to have healthy pregnancies and healthy babies. **4 to 5 in 100** pregnant people get gestational diabetes, at least, says the RCOG ## Who is offered a test? You are offered [a test](https://splash.care/tools/pregnancy-test-timing) if you have any of these risk factors, which your midwife checks at your booking appointment: - A BMI above 30 - A previous baby weighing 4.5kg (about 10lb) or more at birth - Gestational diabetes in an earlier pregnancy - A parent, brother or sister with diabetes - A family background that is South Asian, Black (African-Caribbean) or Middle Eastern. The risk is higher even if you were born in the UK. Many people have no symptoms. Some notice being very thirsty, needing to pee a lot, a dry mouth, tiredness, blurred vision or [thrush](https://splash.care/learn/glossary/thrush), but these are common in pregnancy anyway. ## The test (OGTT) The [Glucose tolerance test](https://splash.care/learn/glossary#ogtt) is a 2-hour test. You do not eat overnight (water is fine). A blood sample is taken, you drink a sugary drink, you rest, and another sample is taken 2 hours later. It is usually at 24 to 28 weeks. If you had gestational diabetes before, you are offered a test or a finger-prick kit earlier, soon after booking, and a repeat at 24 to 28 weeks if the first is normal. NICE says gestational diabetes is diagnosed if the fasting result is 5.6 mmol/l or higher, or the 2-hour result is 7.8 mmol/l or higher. **Quick quiz:** When is the glucose tolerance test usually done? 1. At the booking appointment for everyone 2. At 24 to 28 weeks if you have a risk factor 3. Only after the baby is born Answer: At 24 to 28 weeks if you have a risk factor. If you have a risk factor, the main test is at 24 to 28 weeks. If you had it before, you are offered an earlier check as well. ## If you are diagnosed - You get a blood sugar testing kit and a plan from a specialist team. - Food and activity changes come first. A short walk after meals can help. Ask your team before starting anything new. - If that does not bring your levels down enough, you may be offered tablets or insulin. This is common, and your team will explain what suits you and your baby. - You will usually have extra scans to check your baby’s growth. - Birth is usually advised before 41 weeks, earlier if there are concerns. ## After the baby Gestational diabetes usually goes away after birth, but it raises your chance of type 2 diabetes later. You should be offered a blood test 6 to 13 weeks after birth (this may happen at your 6-week check), and then a check every year. A healthy-weight, active life and the NHS Diabetes Prevention Programme can help lower your risk. > **Splash says:** a diagnosis is not a grade on your eating. Lots of people with no risk factors get it too. Ask your team for a chat with a dietitian, as they make it much less confusing. ### When to see a doctor Tell your midwife if you notice strong thirst, lots of peeing, a dry mouth or blurred vision, rather than waiting. Call your maternity unit straight away about reduced baby movements, severe headache or vision changes. If you are diagnosed, keep your hospital phone number to hand. ## Sources 1. [NHS: Gestational diabetes](https://www.nhs.uk/conditions/gestational-diabetes/) 2. [RCOG: Gestational diabetes](https://www.rcog.org.uk/for-the-public/browse-our-patient-information/gestational-diabetes/) 3. [NICE NG3: Diabetes in pregnancy](https://www.nice.org.uk/guidance/ng3) 4. [Diabetes UK: Gestational diabetes](https://www.diabetes.org.uk/about-diabetes/gestational-diabetes) This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).