Gestational Diabetes: Symptoms, Testing and Management in the UK

Gestational diabetes is a type of diabetes that occurs specifically during pregnancy. It is characterised by high blood sugar (glucose) levels that were not present prior to conception. In the UK, it affects approximately 4% to 5% of pregnancies. During pregnancy, the body produces extra hormones and undergoes various changes, including weight gain. These changes can make the body's cells use insulin less effectively, a condition known as insulin resistance.

Insulin is the hormone responsible for allowing blood sugar to enter cells to be used for energy. Most pregnant women can produce enough extra insulin to compensate for this resistance, but some cannot. When the body cannot produce sufficient insulin, blood sugar levels rise, leading to gestational diabetes. According to NICE (National Institute for Health and Care Excellence) guidance, early detection and careful management are vital to ensure a healthy pregnancy and delivery.

One of the challenges with gestational diabetes is that it often does not cause any obvious symptoms. When symptoms do occur, they are frequently mistaken for normal pregnancy 'niggles'. Potential signs to watch for include:

• Increased thirst: Feeling unusually thirsty despite drinking plenty of fluids.
• Frequent urination: Needing to pass urine more often than usual, especially during the night.
• Dry mouth: A persistent feeling of dryness in the mouth.
• Fatigue: Feeling extremely tired or lethargic (beyond standard pregnancy fatigue).
• Blurred vision: Occasional episodes of blurred or changed vision.

Because these symptoms are common in many pregnancies, the NHS relies on screening for those at higher risk rather than waiting for symptoms to manifest.

In the UK, midwives and GPs assess risk factors at the first antenatal appointment (the booking appointment). You are considered at higher risk if:

• Your Body Mass Index (BMI) is above 30.
• You have previously given birth to a baby weighing 4.5kg (10lbs) or more.
• You had gestational diabetes in a previous pregnancy.
• You have a parent or sibling with diabetes.
• Your family origin is South Asian, Black, African-Caribbean, or Middle Eastern.

If you meet any of these criteria, you will be offered an oral glucose tolerance test (OGTT), usually when you are between 24 and 28 weeks pregnant. This involves fasting overnight, having a blood test, drinking a sugary glucose drink, and having a second blood test two hours later to see how your body processes the sugar.

If you are diagnosed, your care will be managed by a specialist team, typically including a consultant, a specialist midwife, and a dietitian. The primary goal is to control blood glucose levels. NICE guidelines recommend the following strategies:

Blood Glucose Monitoring

You will likely be given a testing kit to check your blood sugar levels multiple times a day—usually before breakfast and one hour after each meal. This helps you and your medical team understand how your body reacts to different foods and activities.

Healthy Eating

A dietitian will help you create a plan focused on 'slow-release' carbohydrates (low glycaemic index) like oats, brown rice, and wholemeal bread. This prevents sharp spikes in blood sugar. Increasing protein and fibre intake is also essential.

Physical Activity

Gentle, regular exercise, such as walking for 30 minutes after meals or swimming, helps the body use insulin more effectively. Always consult your midwife or an online doctor before starting a new vigorous exercise regime during pregnancy.

While many women can manage their blood sugar through diet and exercise alone, some will require medication. If blood sugar targets are not met within one to two weeks of lifestyle changes, the NHS team may prescribe:

• Metformin: A tablet that helps the body use insulin better and reduces the amount of sugar the liver releases.
• Insulin Injections: If Metformin is not suitable or sufficient, you may need to inject insulin to keep your levels stable.

It is important to remember that needing medication does not mean you have failed; it simply means your body needs extra support to keep you and your baby safe.

Navigating a pregnancy diagnosis can be overwhelming. While your NHS maternity team will lead your clinical care, you may wish to speak to a GP online for additional support or clarification. An online doctor can help by:

• Explaining your screening results and what the numbers mean in plain English.
• Discussing the implications of risk factors if you are planning a pregnancy.
• Providing advice on managing pregnancy-related symptoms alongside your diagnosis.
• Reviewing medication side effects and offering lifestyle advice.
• Issuing sick notes if the condition or its management requires time off work.

An online consultation offers a calm, private space to ask the questions you might have forgotten during a busy hospital appointment.

Meticulous management reduces the risk of complications. However, if blood sugar is not controlled, it can lead to macrosomia (a very large baby), which increases the likelihood of an induced labour or a caesarean section. There is also a higher risk of preeclampsia and polyhydramnios (too much amniotic fluid).

After birth, your blood sugar will usually return to normal immediately. You will be advised to stop any diabetes medications and will have a follow-up blood test (usually a fasting glucose test or HbA1c) about 6 to 13 weeks after delivery. Because having gestational diabetes increases your risk of developing Type 2 diabetes later in life, the NHS recommends annual blood sugar checks with your GP surgery.