Gestational Diabetes: Symptoms, Diet, and Management in Europe

Gestational diabetes is one of the most commonly diagnosed pregnancy complications in Europe, affecting approximately 2–5% of pregnancies in the UK and up to 14% in some other European populations depending on the diagnostic criteria used. Despite how common it is, a gestational diabetes diagnosis can feel frightening and overwhelming, particularly if it comes without clear explanation of what it means, what happens next, and what you can do to protect your and your baby’s health. This guide covers everything you need to know about gestational diabetes symptoms, diet, and management — drawing on NICE guidelines for the UK, European clinical guidance, and the practical experience of parents navigating this diagnosis. Whether you’ve just been diagnosed or are trying to understand your risk, this is the evidence-based, jargon-free guide you need.

What Is Gestational Diabetes?

Gestational diabetes mellitus (GDM) is a form of diabetes that develops during pregnancy, typically in the second or third trimester, in women who have not previously had diabetes. It occurs when the hormones of pregnancy — particularly human placental lactogen, progesterone, and cortisol — cause insulin resistance in the mother’s cells. The pancreas normally compensates by producing more insulin, but in some women, insulin production cannot keep pace with demand, resulting in elevated blood glucose levels.

GDM is distinct from pre-existing type 1 or type 2 diabetes, though the management of blood glucose during pregnancy shares important similarities. In most cases, GDM resolves after birth, but it significantly increases the lifetime risk of developing type 2 diabetes: approximately 50% of women with GDM develop type 2 diabetes within 10 years of their pregnancy.

Risk factors for GDM include:

• BMI above 30kg/m²
• Previous GDM in an earlier pregnancy
• A family history of type 2 diabetes (first-degree relative)
• South Asian, Black, Middle Eastern, or East Asian ethnicity (higher inherent risk)
• Previous birth of a baby weighing over 4.5kg (macrosomia)
• Polycystic ovary syndrome (PCOS)

Symptoms and Diagnosis

One of the most challenging aspects of GDM is that it frequently produces no symptoms — which is why routine screening in pregnancy is so important. When symptoms do occur, they may include:

• Increased thirst and frequent urination (beyond normal pregnancy urination)
• Fatigue (distinguishable from normal pregnancy fatigue by its severity)
• Blurred vision
• Recurrent infections, particularly urinary tract or thrush infections

Diagnosis is made through the Oral Glucose Tolerance Test (OGTT), also called the Glucose Challenge Test in some European countries. In the UK, NICE guidelines recommend offering an OGTT at 24–28 weeks to women with identified risk factors. The test involves fasting overnight, having a blood glucose measurement, drinking a standard glucose solution, and having a second blood glucose measurement two hours later. NICE diagnostic thresholds are fasting glucose of 5.6mmol/L or above, or a 2-hour value of 7.8mmol/L or above.

Diagnostic thresholds vary across Europe: the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria — used in many EU countries — set slightly different thresholds (fasting 5.1mmol/L, 1-hour 10.0mmol/L, 2-hour 8.5mmol/L). This variation means that a woman diagnosed in France or Germany might not meet UK diagnostic criteria, and vice versa — a fact that causes significant confusion for expat families and is worth understanding.

Dietary Management: What to Eat and Avoid

Dietary management is the cornerstone of GDM care and is effective in controlling blood glucose in the majority of women without the need for medication. The goals are to maintain blood glucose within target ranges, avoid large post-meal glucose spikes, meet nutritional requirements for pregnancy, and gain appropriate weight.

The GDM diet is not a “no carbohydrate” diet — it is a “managed carbohydrate” diet. Carbohydrates are needed for energy, fetal development, and the mother’s wellbeing, but the type and quantity matter enormously:

• Prioritise low-glycaemic index (GI) carbohydrates: Oats, wholegrain bread, brown rice, quinoa, sweet potato, legumes, and most fruits have a lower GI than white bread, white rice, or sugary foods, meaning they cause a slower, more manageable rise in blood glucose.
• Distribute carbohydrates evenly across meals and snacks: Eating small amounts of carbohydrate regularly, rather than large quantities in one sitting, prevents glucose spikes. Most GDM dietitians recommend 3 meals and 2–3 snacks per day.
• Breakfast is particularly important: Morning insulin resistance is highest, making breakfast the most challenging meal for blood glucose management. Many women with GDM find they need to significantly reduce carbohydrate at breakfast — for example, eggs with vegetables rather than cereal or toast.
• Pair carbohydrates with protein and fat: Protein and fat slow gastric emptying, reducing the speed of glucose absorption. Adding cheese, eggs, nuts, or avocado to carbohydrate-containing meals and snacks improves post-meal glucose responses.

Foods to limit or avoid include: sugary drinks (including fruit juice), white bread and white rice, cakes, biscuits, sweets, chocolate, and processed cereals with high sugar content.

Monitoring Blood Glucose

In the UK, NICE recommends that women with GDM monitor their own blood glucose using a glucometer, testing before breakfast (fasting) and one hour after each main meal. NICE target ranges are:

• Fasting: 5.3mmol/L or below
• 1 hour after meals: 7.8mmol/L or below

Regular monitoring allows you to see how specific foods affect your glucose levels — what works for one person may not work for another, and self-monitoring is essential to personalise your diet. Recording your readings in a logbook (paper or digital) allows your diabetes team or midwife to review your management at appointments and adjust treatment if needed.

If dietary changes alone are insufficient to maintain blood glucose within target ranges — which occurs in approximately 10–20% of GDM cases — medication will be considered. Metformin (an oral medication) is the first-line option in NICE guidelines; insulin injections are used if Metformin is not tolerated or sufficient. Both are safe in pregnancy and widely used.

Management During Labour and After Birth

Women with GDM are recommended by NICE to give birth by 40+6 weeks at the latest, with induction of labour or elective caesarean offered at this point. Earlier induction may be recommended depending on glucose control and baby’s growth. During labour, blood glucose is monitored regularly; insulin infusion may be required to maintain glucose within a safe range, particularly if labour is prolonged or if any interventions affect eating.

After birth, GDM typically resolves rapidly — blood glucose should be checked in the first few hours postnatally. At 6–13 weeks postnatally, NICE recommends a fasting plasma glucose test to ensure glucose has returned to normal. Women who have had GDM should be informed of their increased lifetime risk of type 2 diabetes and offered annual diabetes screening by their GP — a healthy weight, regular physical activity, and a balanced diet significantly reduce this risk.

Frequently Asked Questions

Will I definitely need insulin if I have gestational diabetes?

No. The majority of women with GDM manage their condition through diet and lifestyle changes alone. Approximately 10–20% require medication — either oral Metformin or insulin injections — if diet is insufficient. The need for medication does not indicate a more serious condition or a failure on your part; it reflects the degree of insulin resistance in your specific pregnancy.

Does gestational diabetes mean my baby will be diabetic?

GDM does not cause diabetes in your baby. However, babies of mothers with GDM are at slightly higher risk of developing type 2 diabetes in later life, and the baby’s blood glucose is checked after birth (via heel prick test) to ensure it has not been affected by high maternal glucose. Babies born to mothers with poorly controlled GDM may be larger than average (macrosomia), which carries its own birth complications, and are at slightly higher risk of low blood glucose in the neonatal period.

Can exercise help manage gestational diabetes?

Yes, significantly. Physical activity improves insulin sensitivity and is an evidence-based management tool for GDM, supported by NICE and European diabetes guidelines. Even a 30-minute walk after meals can meaningfully reduce post-meal glucose levels. As always, discuss exercise plans with your midwife or diabetes team, particularly if you have complications.

What is the difference in GDM diagnosis criteria across Europe?

Diagnostic criteria vary significantly across Europe. The UK uses NICE criteria; many EU countries use IADPSG criteria (which are slightly more sensitive and catch more cases). This means prevalence statistics are not directly comparable between countries, and some women may find their diagnosis would differ if they were in a different country. If you’re an expat, it’s worth confirming which criteria your healthcare provider is using and ensuring your management is guided by whichever criteria apply to your care setting.

Take Control: Your Next Steps After a GDM Diagnosis

If you’ve just been diagnosed with gestational diabetes, the most important next step is to request a referral to a specialist diabetes and pregnancy dietitian, which NICE recommends as part of standard GDM care. They will work with you to develop a personalised eating plan. Alongside this, begin monitoring your blood glucose as directed and start your testing logbook. GDM is a very manageable condition with the right support, and the vast majority of women with GDM go on to have healthy pregnancies and healthy babies.