By: Dr Elie Servan-Schreiber (Gynécologue-obstétricien) — 21/02/2026
In brief
Gestational diabetes affects 10 to 15% of pregnancies in France. It is screened between 24 and 28 weeks of gestation using the OGTT test. With an adapted diet, the vast majority of cases can be managed without insulin. It disappears after delivery in about 90% of cases, but long-term follow-up remains necessary.
Gestational diabetes is a glucose tolerance disorder that appears for the first time during pregnancy, usually in the second or third trimester. Unlike type 1 or type 2 diabetes which preexist before conception, gestational diabetes is directly linked to the hormonal changes caused by pregnancy.
The mechanism is as follows: the placenta produces hormones (notably human placental lactogen, cortisol, and progesterone) that progressively increase insulin resistance in the mother. The pancreas must then produce more insulin to maintain normal blood sugar levels. When the pancreas can no longer compensate for this increased resistance, blood sugar rises and gestational diabetes develops.
According to Santé Publique France, gestational diabetes affects between 10 and 15% of pregnancies in the country, and its prevalence is steadily increasing in recent years, notably due to the rise in maternal age and the prevalence of overweight. Blood sugar during pregnancy must therefore be monitored carefully, even in the absence of symptoms.
Not all pregnant women have the same risk of developing gestational diabetes. Several factors significantly increase the likelihood of being affected:
If you have one or more of these factors, your doctor or midwife may offer you early screening from the first trimester.
This is one of the most confusing aspects of gestational diabetes: in the vast majority of cases, it causes no symptoms. This is precisely why systematic screening is so important. A woman may have high blood sugar levels during pregnancy without realizing it.
However, certain signs may sometimes raise concern, although they are easily confused with the usual discomforts of pregnancy:
Among the symptoms of gestational diabetes, none is truly specific. Most women discover their gestational diabetes during systematic screening between 24 and 28 weeks of gestation. Do not wait to experience symptoms before taking the test.
Gestational diabetes screening relies on a test called OGTT (oral glucose tolerance test), also known as the gestational diabetes test. It is offered to all pregnant women who have at least one risk factor, and increasingly on a systematic basis.
The OGTT is performed between 24 and 28 weeks of gestation, the period when placenta-related insulin resistance reaches its peak. If you have significant risk factors, your doctor may also prescribe a fasting blood glucose test from the first trimester. A fasting blood glucose level of 0.92 g/L or higher in the first trimester is sufficient to establish the diagnosis.
The test is carried out at the laboratory, in the morning, after fasting for at least 8 hours. You ingest 75 g of glucose dissolved in water. Three blood samples are then taken: fasting, then 1 hour and 2 hours after the glucose ingestion.
According to the IADPSG criteria (International Association of Diabetes and Pregnancy Study Groups), adopted by the WHO and used by the HAS in France, the diagnosis of gestational diabetes is established when even a single value reaches or exceeds the following thresholds:
A single abnormal value is sufficient to establish the diagnosis. These gestational diabetes thresholds are now the international standards.
When left untreated, gestational diabetes can lead to complications for both the mother and the baby. It is however essential to keep in mind that these risks are considerably reduced with appropriate medical follow-up and a suitable diet.
The main risk of gestational diabetes for the baby is macrosomia, meaning a birth weight above 4 kg. When the mother has high blood sugar, glucose crosses the placenta and stimulates the baby's pancreas, which produces more insulin. This fetal hyperinsulinemia promotes fat storage and excessive growth.
Other risks of gestational diabetes for the baby include:
Rest assured: with proper medical follow-up, an adapted diet, and possibly insulin treatment, the vast majority of pregnancies with gestational diabetes go very well. Serious complications remain rare when blood sugar is controlled.
Diet is the first-line treatment for gestational diabetes. This is excellent news, as it means you have real power to take action. According to the HAS, 80 to 90% of gestational diabetes cases can be controlled through diet alone, without the need for insulin.
A gestational diabetes diet does not mean eating less, but eating better. It is by no means a restrictive diet: pregnancy is not the time to drastically reduce caloric intake. The goal is to distribute carbohydrates evenly throughout the day and to favor those with a low glycemic index.
Here are the main principles of a gestational diabetes diet:
If you suffer from pregnancy nausea, splitting your meals can also help you better tolerate food while controlling your blood sugar.
To know concretely what to eat with gestational diabetes, here is a summary table of foods to favor and those to limit or avoid. This list will help you plan your daily menus.
Foods to favor
Foods to limit or avoid
If you follow a vegetarian or vegan diet during pregnancy, legumes and tofu are excellent low glycemic index protein sources, perfectly suited to a gestational diabetes diet.
Breakfast is the most critical meal when you have gestational diabetes. Why? Because insulin resistance is at its peak in the morning, after the overnight fast. Carbohydrates consumed upon waking cause higher blood sugar spikes than those eaten at lunch or dinner. It is therefore essential to pay special attention to what you eat for breakfast.
What you absolutely must avoid at breakfast: orange juice (even freshly squeezed), sugary cereals, pastries (croissants, chocolate croissants), white bread with jam, honey in large amounts. All these foods cause a sharp, hard-to-control blood sugar spike.
The winning formula for a gestational diabetes breakfast: a source of protein + a low GI starch + a fruit (at the end of the meal) + a hot drink without sugar.
Breakfast n°1: The savory classic
Breakfast n°2: The protein bowl
Breakfast n°3: The express
Find more ideas in our complete guide to the ideal breakfast for pregnant women, adapting the suggestions to the low GI diet principles detailed here.
Here is a gestational diabetes menu for a full day, illustrating the principle of meal splitting (3 meals + 2 snacks) and low glycemic index.
Breakfast (7:30 AM)
1 slice of whole grain bread + butter, 1 hard-boiled egg, 30 g of hard cheese, a few strawberries, 1 green tea without sugar.
Morning snack (10:00 AM)
1 plain yogurt + 1 handful of walnuts (about 30 g).
Lunch (12:30 PM)
Green lentil salad with crunchy vegetables (cucumber, tomatoes, bell peppers), 1 grilled chicken breast, 1 tablespoon of olive oil, 1 slice of whole grain bread, 1 apple for dessert.
Afternoon snack (4:00 PM)
1 slice of rye bread + 1 portion of fresh cheese, or 2 squares of dark chocolate (70% cocoa minimum) + a few almonds.
Dinner (7:30 PM)
Baked salmon fillet, quinoa (150 g cooked), steamed broccoli, 1 drizzle of olive oil, 1 pear for dessert.
This menu is an indicative example. Portions and food choices should be adapted to your individual caloric needs, defined with your dietitian or doctor. The fundamental principle remains the same: moderate amounts of complex carbohydrates, protein and fiber at every meal, and snacks to avoid blood sugar fluctuations.
Once the diagnosis is made, blood sugar self-monitoring becomes a daily companion. It allows you to verify that your diet is sufficient to control your blood sugar during pregnancy and to adjust treatment if necessary.
Self-monitoring is done using a capillary blood glucose meter (a small finger prick). Your doctor will generally ask you to measure your blood sugar 4 to 6 times per day: a fasting measurement in the morning, then 2 hours after each main meal (breakfast, lunch, dinner).
Record each result in a monitoring log (paper or mobile app) along with the contents of your meals. This log is a valuable tool during your appointments: it allows the doctor to identify when blood sugar spikes occur and to identify the foods responsible.
If, despite a well-followed diet for 1 to 2 weeks, your blood sugar levels remain above the targets, your doctor may prescribe insulin. According to the CNGOF, this applies to 10 to 20% of gestational diabetes cases. Insulin does not cross the placenta and is therefore safe for the baby. Oral anti-diabetic medications (such as metformin) are not recommended as first-line treatment in France during pregnancy, although their use is discussed in certain situations.
Here is the good news: gestational diabetes disappears in about 90% of cases after the placenta is delivered. As soon as the placenta is expelled, the hormones responsible for insulin resistance drop sharply and blood sugar normalizes quickly.
However, having had gestational diabetes is not without long-term consequences. Studies show that the risk of developing type 2 diabetes in the 5 to 10 years following pregnancy is considerably increased: according to Santé Publique France, up to 50% of women who had gestational diabetes will develop type 2 diabetes during their lifetime.
This is why rigorous follow-up is recommended after delivery:
For advice on postpartum weight management, see our article losing weight after pregnancy.
« Gestational diabetes is often a source of anxiety for patients, but it is important to remember that it can be managed very well in the vast majority of cases. Diet is truly the cornerstone of treatment. I encourage my patients to see this period not as a constraint, but as an opportunity to adopt dietary habits that are beneficial for the whole family. Splitting meals, choosing low glycemic index foods, and regular blood sugar monitoring are sufficient in 80 to 90% of cases. And even when insulin is necessary, it is perfectly safe for the baby. »
Dr Elie Servan-Schreiber, obstetrician-gynecologist
Gestational diabetes is a glucose tolerance disorder that appears for the first time during pregnancy. It is caused by placental hormones that increase insulin resistance. It affects 10 to 15% of pregnancies in France and is distinct from type 1 or type 2 diabetes which preexist before pregnancy.
If left untreated, it can lead to macrosomia (baby over 4 kg), neonatal hypoglycemia, or difficult delivery. However, with appropriate management (diet and possibly insulin), these risks are considerably reduced. The vast majority of pregnancies with gestational diabetes go very well.
Screening relies on the OGTT (oral glucose tolerance test) performed between 24 and 28 weeks of gestation. After ingesting 75 g of glucose, three blood samples are taken (fasting, at 1 hour, and at 2 hours). A single value exceeding the thresholds (0.92 g/L fasting, 1.80 g/L at 1 hour, 1.53 g/L at 2 hours) is sufficient to establish the diagnosis.
You should limit fast sugars (sodas, fruit juices, candy), white bread, pastries, potatoes (especially mashed: very high GI), white rice, overcooked white pasta, honey and jam in large amounts, and sugary breakfast cereals.
Choose a savory or low-sugar breakfast: 1 slice of whole grain bread with butter, 1 egg or cheese, 1 fresh fruit (at the end of the meal), and 1 hot drink without sugar. Absolutely avoid orange juice, sugary cereals, and pastries, as insulin resistance is at its peak in the morning.
Yes, in about 90% of cases, gestational diabetes disappears after the placenta is delivered. However, it increases the risk of developing type 2 diabetes later on (up to 50% of women affected). A blood sugar check at 6 weeks postpartum then annual monitoring are recommended.
Blood sugar targets during pregnancy in cases of gestational diabetes are: below 0.95 g/L fasting and below 1.20 g/L two hours after meals. For screening, the diagnostic thresholds are: 0.92 g/L fasting, 1.80 g/L at 1 hour, and 1.53 g/L at 2 hours after glucose ingestion.
No. Insulin is only necessary in 10 to 20% of cases, when diet alone is not enough to control blood sugar after 1 to 2 weeks of trying. 80 to 90% of gestational diabetes cases are managed through diet alone. When prescribed, insulin is safe for the baby as it does not cross the placenta.
Yes. Women who had gestational diabetes have an increased risk of developing type 2 diabetes in the 5 to 10 years following pregnancy. This risk can reach 50% over a lifetime. Breastfeeding, regular physical activity, and maintaining a balanced diet can significantly reduce this risk.
Yes, fruits are not forbidden. They provide essential vitamins, fiber, and minerals. The rule is to eat them at the end of a meal (never alone as a snack without protein), to limit portions to 1 to 2 servings per meal, and to favor low GI fruits such as apples, pears, strawberries, and berries rather than very ripe bananas or grapes.
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