Short answer: Gestational diabetes is high blood sugar that develops in pregnancy because your body can't make enough extra insulin to meet pregnancy's demands. It usually goes away after birth. It isn't your fault, and good management greatly reduces the risks for you and your baby. Treatment starts with diet changes and regular activity; some people also need metformin or insulin. You'll check your blood sugar at home and be monitored more closely. After the birth, you should be offered a blood test to check the diabetes has gone, and regular checks after that.
The result comes back and it's a shock. Diabetes — something you associate with lifelong illness, when you're “just” pregnant. Here's what it actually means.
What it is
In pregnancy, your body needs more insulin to keep blood sugar in a healthy range. If it can't produce enough extra, blood sugar rises: that's gestational diabetes. Any pregnant woman can develop it, but some things raise the chance, such as a higher BMI, a previous baby weighing 4.5kg or more, gestational diabetes in a previous pregnancy, a parent or sibling with diabetes, or South Asian, Black Caribbean or Middle Eastern family origin.
You didn't cause this by eating the wrong thing. It's your body's response to pregnancy — and it's very treatable.
Why it's treated
High blood sugar passes to your baby, who may grow larger than usual. That can make birth more difficult and increase the likelihood of induction or a caesarean. Other risks include too much amniotic fluid, and your baby having low blood sugar or jaundice after birth. Stillbirth is a rare risk. Controlling your blood sugar reduces these risks — which is why screening and treatment matter.
Checking your blood sugar
You'll be given a finger-prick testing kit and shown how to use it. You'll usually test before breakfast and one hour after each meal, and share your readings with your care team. It feels like a lot in the first week; for most people it soon becomes routine. Noting what you ate alongside unusual readings helps you spot which meals are harder for your body.
What you can do
Food
You'll usually be referred to a dietitian. Common advice includes:
- eating regular meals and avoiding skipping meals;
- spreading carbohydrates through the day and choosing slower-release options, such as wholegrains, pulses and vegetables;
- pairing carbohydrates with protein;
- avoiding sugary drinks — fruit juice and smoothies can also be high in sugar.
Activity
Physical activity lowers blood sugar. A common recommendation is at least 150 minutes of moderate activity a week, such as brisk walking, plus strength exercises on two or more days, if safe for you. Many people find a short walk after meals helps their readings.
Medicine
If your blood sugar isn't stable after one to two weeks of changes, or is very high when you're diagnosed, you may be offered tablets (usually metformin) or insulin. That isn't failure — blood sugar often rises as pregnancy progresses, and some bodies simply need more help. You can usually stop these medicines after the birth.
What it means for the birth
You'll be monitored more closely, often with extra scans to check your baby's growth. You may be advised to give birth a little earlier than your due date, by induction or caesarean, depending on your situation. Ask your team to explain your options. After birth, your baby's blood sugar will be checked and early feeding is encouraged.
After the birth
Gestational diabetes usually goes away after birth, but it does raise your risk of type 2 diabetes later in life. UK guidance (NICE) recommends offering a fasting blood glucose test 6 to 13 weeks after the birth (or an HbA1c test later), and an annual HbA1c test after that if the result is normal. Staying active and eating well lowers your future risk, and in England you can refer yourself to the NHS Diabetes Prevention Programme.
When to get help
Contact your care team if your readings are often outside your target range, if you're on insulin and have signs of low blood sugar (shaky, sweaty, hungry, pale or struggling to concentrate), or if you notice increased thirst, peeing a lot, or tiredness despite treatment. Always contact your maternity unit straight away if your baby's movements slow down or change.
Related reading
From pregnancy onwards: The First 1000 Days (PDF, English) covers the period from pregnancy to age two.
Sources
- NHS — Gestational diabetes and Treatment.
- NICE — Diabetes in pregnancy: management from preconception to the postnatal period (NG3).
Written by the Bloom Guides editorial team. Last updated: 20 October 2026. General information only — not a substitute for advice from your midwife, diabetes team or doctor.