Diabetes Gestational

Overview

Gestational diabetes is a type of high blood sugar that develops during pregnancy, usually in the second half. It happens when your body cannot make enough of a hormone called insulin, or the insulin it makes does not work well enough. Insulin acts like a key that lets sugar from your food move out of your blood and into your cells for energy. During pregnancy, hormones from the placenta can make your body less sensitive to insulin, so your blood sugar rises. Gestational diabetes is not the same as type 1 or type 2 diabetes, and for most people it goes away after the baby is born.

Yes, it is common. It affects roughly 1 in 7 pregnancies worldwide, and rates vary between countries and communities. In the UK, around 1 in 20 to 1 in 30 pregnant people are diagnosed.

It can affect any pregnant person, but it is more likely in people who are older (especially over 35), have a higher body weight, have a family history of diabetes, have had gestational diabetes before, or come from certain ethnic backgrounds where type 2 diabetes is more common, such as South Asian, Black, African-Caribbean, or Middle Eastern families.

Symptoms

Common symptoms

• Most people have no symptoms at all — this is why the screening test is offered.
• Feeling more thirsty than usual.
• Needing to pass urine more often, especially at night.
• Feeling very tired, though tiredness is also common in normal pregnancy.
• Blurred vision now and then.
• Getting infections more easily, such as urine infections or thrush.

Symptoms in children

• Not applicable. Gestational diabetes only happens during pregnancy, so it does not affect children.

Symptoms in older adults

• Not applicable as a new diagnosis, because it only occurs during pregnancy. However, the risk of gestational diabetes rises with age, and it is more common in pregnancies over the age of 35. People who had it in the past should be checked for type 2 diabetes as they get older.

Causes

Main causes

• Pregnancy hormones made by the placenta make your body less able to use insulin well. This is called insulin resistance.
• Your body cannot make the extra insulin needed to keep blood sugar in the normal range.
• The placenta grows larger in later pregnancy, so the effect usually shows up in the second or third trimester.
• It is not caused by eating sweets or by anything you did or did not do.

Risk factors

• Being over 25, and especially over 35.
• Having a body mass index (BMI) above 30 before pregnancy.
• Having had gestational diabetes in an earlier pregnancy.
• Having a parent, brother, or sister with diabetes.
• Family background where type 2 diabetes is more common, such as South Asian, Black, African-Caribbean, or Middle Eastern.
• Previously having a baby weighing over 4.5 kg (about 10 lb).
• Having polycystic ovary syndrome (PCOS), a hormone condition that affects periods.
• Some medicines, such as steroids, can raise blood sugar.

When to see a doctor

See a doctor urgently if:

• Your baby's movements slow down or change — call your maternity unit right away.
• Severe headache, vision changes, or sudden swelling — get seen the same day.
• You feel very unwell, dizzy, or cannot keep food or drink down.
• You have signs of a urine infection or any fever.
• Your home blood sugar readings are very high or very low and will not settle.

Book a routine appointment if:

• You are planning a pregnancy and have risk factors — ask about early testing.
• You are pregnant and have not been offered a screening test but have risk factors.
• You have had gestational diabetes before and are pregnant again.
• You gave birth in the last year and have not yet had your follow-up blood test.
• You have questions about meal planning, exercise, or home blood sugar checks.

Diagnosis

Gestational diabetes is usually found with a screening test offered between 24 and 28 weeks of pregnancy, or earlier if you have risk factors. You will be asked to fast overnight, have a blood test, drink a sweet glucose drink, then have more blood tests over the next two hours. This shows how well your body handles sugar. Sometimes sugar is first spotted in a routine urine sample, and your team will then arrange blood tests.

Tests that may be done

• Oral glucose tolerance test (OGTT): a fasting blood test, a sugary drink, then repeat blood tests at one and two hours.
• Random blood sugar test, if you have symptoms or sugar in your urine.
• Home blood sugar monitoring: a small finger-prick test you do yourself, once diagnosed, to track levels through the day.
• Blood tests to check your overall health and iron levels.
• Ultrasound scans later in pregnancy to check your baby's growth.
• Blood pressure and urine checks at each antenatal visit.

What to expect at your appointment

The screening test takes about two to three hours, and you will need to stay at the clinic during that time. If you are diagnosed, you will usually be referred to a specialist diabetes in pregnancy team. They will show you how to check your blood sugar, help with meal planning, and arrange extra appointments. You will usually have more frequent antenatal checks and growth scans, and your team will talk with you about the best timing and plan for birth.

Treatment

Treatment aims to keep your blood sugar in a healthy range so you and your baby stay well. Most people manage it with healthy eating, regular gentle activity, and checking blood sugar at home. Some people also need medicine, which your specialist team will discuss with you. You will have closer monitoring, including extra scans, and your team will plan the safest time and way for you to give birth.

Self-care at home

• Check your blood sugar at the times your team advises, and write the readings down or use an app.
• Eat regular meals and snacks, and choose slow-release carbohydrates such as whole grains, beans, and vegetables.
• Pair carbohydrates with protein or healthy fats to keep blood sugar steadier.
• Stay active — a 10 to 15 minute walk after meals can help your body use sugar better.
• Keep a water bottle handy and drink regularly.
• Take your iron and vitamin supplements as advised, and ask before starting anything new.
• Get plenty of rest and accept offers of help — extra appointments can be tiring.

Medical treatments

If healthy eating and activity are not enough, your specialist team may prescribe medicine to help control your blood sugar. This is given in a form that is safe in pregnancy, and your team will explain the options, teach you how to use them, and adjust the plan as your pregnancy progresses. You will also have more frequent antenatal appointments, blood pressure checks, and growth scans so your team can keep a close eye on you and your baby.

When is surgery considered?

Surgery is not a treatment for gestational diabetes. However, your team may recommend a caesarean birth if there are concerns about your baby's size, your blood sugar control, or your own health. This will always be discussed with you so you can make an informed choice.

Living with this condition

Day to day, gestational diabetes means planning meals a little more carefully, checking blood sugar a few times a day, and fitting in extra clinic visits. It can feel like a lot at first, but most people find a routine within a few weeks. Write down questions as they come up and bring them to your appointments. Keep your readings and meal ideas in one place so your team can see what is working.

Lifestyle tips

• Eat three meals a day, with small snacks if needed, rather than long gaps without food.
• Choose wholegrain bread, brown rice, oats, and lentils instead of white or sugary versions.
• Include vegetables, beans, eggs, fish, lean meat, or tofu with meals.
• Limit sugary drinks, sweets, and fruit juice — water or unsweetened drinks are best.
• Aim for gentle activity most days, such as walking, swimming, or antenatal classes.
• Keep a snack with you in case your blood sugar dips.
• Avoid alcohol and smoking, and ask your team for support if you need help quitting.
• Get enough sleep and rest when you can.

Diet and exercise

You do not need a strict or special diet. A balanced way of eating with regular meals, plenty of vegetables, and slower-release carbohydrates keeps blood sugar steadier. Eating the same amount at similar times each day helps your team spot patterns. Gentle, regular movement — like a walk after a meal — helps your muscles use sugar without needing extra insulin. Your team can refer you to a dietitian, who can tailor a plan to your tastes, culture, and budget.

Mental health and emotional wellbeing

It is very normal to feel anxious, upset, or guilty after a diagnosis. Some people feel watched or judged, and extra appointments can be stressful. Remember that gestational diabetes is caused by pregnancy hormones, not by anything you did. Talk to your midwife or doctor if you feel low, worried, or not like yourself — support is available, and asking for it is a sign of strength. If you ever feel hopeless or have thoughts of harming yourself, contact your local crisis line or emergency services right away.

Prevention

Gestational diabetes cannot always be prevented, because pregnancy hormones play a big part. But you can lower your chance of developing it — and lower your chance of type 2 diabetes later — by aiming for a healthy weight before pregnancy, eating a balanced diet, and staying active. If you are planning a pregnancy and have risk factors, talk to your doctor or nurse beforehand so you can get the right checks early.

Vaccines

There is no vaccine for gestational diabetes. Routine vaccinations in pregnancy, such as flu and whooping cough, are still recommended because they protect you and your baby. Ask your midwife which ones are right for you.

Screening programmes

Screening is offered to everyone with risk factors, usually between 24 and 28 weeks of pregnancy. It is also offered earlier if you have had gestational diabetes before or have strong risk factors. After your baby is born, you should be offered a follow-up blood sugar test, usually around 6 to 13 weeks later, and then a yearly check. This is important because having gestational diabetes raises your chance of type 2 diabetes in later life.

Complications

If left untreated

• Your baby may grow larger than average, which can make birth harder and increase the chance of a caesarean.
• There is a higher chance of shoulder problems for the baby during birth.
• Your baby may have low blood sugar or jaundice (yellowing of the skin) just after birth and need extra monitoring.
• There is a higher chance of early labour or of your baby needing special care after birth.
• You may be more likely to develop high blood pressure problems in pregnancy, such as pre-eclampsia.
• There is a higher chance of type 2 diabetes for you in later life.

Long-term outlook

The outlook is good for most people. With regular monitoring and support, many pregnancies with gestational diabetes go smoothly, and blood sugar usually returns to normal within hours or days of birth. Once you have had it, you will be offered follow-up tests to keep an eye on your long-term health. Many people find that the healthy habits they build during pregnancy stay with them, and that is a real, lasting benefit for you and your family.

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