Gestational diabetes – Is it dangerous? How is it detected and treated?

Gestational diabetes is one of the most common pregnancy complications and often affects women who were previously completely healthy. Since it usually causes no typical symptoms, it is difficult to detect – which is why screening tests are invaluable. The most important measure in treatment is an appropriate pregnancy diet.

What is gestational diabetes?

Gestational diabetes is a condition of elevated blood sugar levels (hyperglycemia) caused by impaired glucose tolerance during pregnancy. This means that blood sugar levels remain persistently above normal. The condition occurs only during pregnancy and is among the most common complications during this period. It often affects women who had no prior health issues of this kind, though not exclusively. Women with congenital insulin production disorders or pre-existing insulin resistance are also at risk.

Additionally, pregnant women with previously undiagnosed diabetes are particularly vulnerable. Early and comprehensive treatment greatly improves outcomes for both mother and child. Untreated gestational diabetes is especially dangerous because it typically has no clear symptoms – increasing the risk to the unborn child. However, it can be diagnosed early in pregnancy.

What causes gestational diabetes?

The development of gestational diabetes is complex and multifactorial. The primary cause lies in changes to carbohydrate metabolism and the body’s impaired ability to adapt, particularly due to increasing insulin resistance, which is amplified by hormonal fluctuations and other internal and external factors. Risk increases significantly with excess weight – fat tissue stimulates insulin production, leading to hyperinsulinemia, which further promotes fat accumulation: a vicious cycle.

Age also plays a role – the older the expectant mother, the less capable the body often is at compensating for hormonal changes. Gestational diabetes occurs especially often in women over the age of 35. Other risk factors include high blood pressure, gestational diabetes in previous pregnancies, and a family history of diabetes.

Symptoms of gestational diabetes

The symptoms of gestational diabetes are nonspecific, which makes early diagnosis difficult. Many affected women report general discomfort or fatigue – often interpreted as normal pregnancy symptoms.

Typical (though not definitive) signs include:

• Frequent urination
• Fatigue
• Drowsiness
• Dizziness
• Increased exhaustion
• Cravings
• Intense thirst or dry mouth

Weight gain during pregnancy is normal and not automatically an indicator of diabetes, but in combination with being overweight, it can be a risk factor.

How is gestational diabetes diagnosed?

Despite a lack of symptoms, gestational diabetes can be diagnosed early – through specialized lab tests recommended at the first gynecological appointment. Women with higher risk factors (e.g., family history, overweight) should be monitored regularly even before a planned pregnancy.

A fasting blood glucose level of 100 mg/dL (5.6 mmol/L) is considered the upper limit. If the value is between 100 and 125 mg/dL, an oral glucose tolerance test (OGTT) – also known as a “sugar curve” – is performed. Pregnant women with normal results require no further testing beyond routine checks. Abnormal results call for regular follow-up tests. The test uses venous blood.

Is gestational diabetes dangerous for the baby?

In the first trimester, gestational diabetes can be particularly dangerous because the baby’s organ development (organogenesis) is in full swing. Possible birth defects primarily affect:

• The heart and central nervous system
• Arterial malformations
• Anencephaly (absence of large parts of the brain)
• Spina bifida (open spine)
• Underdevelopment of legs or pelvis

Early and consistent treatment can significantly reduce risks. It is crucial to maintain stable blood sugar levels throughout the entire pregnancy.

Possible complications

Later complications for the child are usually metabolic in nature, such as:

• Hyperglycemia
• Hypocalcemia
• Excessive birth weight (macrosomia), which may necessitate a C-section
• Birth injuries
• Breathing difficulties (meconium aspiration)
• Increased susceptibility to infections

Rarely, there may be enlargement of the pancreatic islets (Langerhans cells). Psychomotor development delays or later tendencies toward obesity, type 2 diabetes, and metabolic syndrome are also possible.

How is gestational diabetes treated?

Treatment should be interdisciplinary – involving diabetologists, nutritionists, and gynecologists. The goal is to stabilize blood sugar levels. The White classification distinguishes between:

• Type G1: Diet alone is sufficient
• Type G2: Insulin therapy is necessary

Light, regular exercise is also helpful but must be adapted to the stage of pregnancy and the woman’s fitness level.

How does insulin therapy work?

Insulin is injected subcutaneously (under the skin). Dosage and timing are individualized. If blood sugar is high in the morning, a fast-acting insulin injection before breakfast is required. If high in the evening, a long-acting dose before bedtime may be needed. Therapy is always conducted under medical supervision.

General recommendations for gestational diabetes:

• Check blood sugar at least 4 times daily (fasting and after meals)
• Maintain a healthy, balanced diet
• Exercise regularly to improve insulin sensitivity
• Keep weight within a healthy range
• Eat a low-sugar diet
• Follow insulin therapy as prescribed
• Get regular ultrasound checks to monitor the baby

Nutrition in gestational diabetes – What to eat and what to avoid?

The diet should resemble that for type 2 diabetes:

• Caloric intake based on body weight (approx. 35 kcal/kg for normal BMI, 25 kcal/kg for overweight individuals)
• 5–6 small, regular meals
• Carbohydrates from whole grains, proteins, healthy fats (e.g., from fish, plant oils, legumes)
• Few processed foods
• Gentle cooking methods: steaming, boiling, braising
• Alternatives: e.g., yogurt with homemade muesli instead of sweetened fruit yogurt

After birth

After delivery, the special diet can be stopped. However, blood sugar should continue to be monitored for about 7–10 days. If insulin was used and the dose was <10 units, it can usually be discontinued immediately. Higher doses should be tapered gradually. Follow-up is coordinated with the doctor and midwife.

Gestational diabetes – Did you know…?

• One in ten pregnant women develops gestational diabetes.
• The recurrence rate in a subsequent pregnancy is 30–69%.
• 18–50% of affected women later develop type 2 diabetes.
• Many women permanently change their diet due to the diagnosis.
• Stress impacts diabetes risk during pregnancy.
• Gestational diabetes is not a sentence – good self-care significantly reduces complications.

FAQ

What is gestational diabetes?
A condition where insulin production is impaired, leading to high blood sugar. It affects approximately 1 in 25 pregnancies.

What tests are performed?
The oral glucose tolerance test (OGTT), recommended between the 24th and 28th week of pregnancy, is the standard.

How is it treated?
By adjusting diet and physical activity. Insulin is administered if necessary.