Gestational diabetes

What is gestational diabetes?

Gestational diabetes, also known as pregnancy diabetes, is a metabolic disorder characterized by hyperglycemia (high blood sugar levels) that first appears during pregnancy. This condition generally occurs in the second or third trimester and often disappears after childbirth. It is a pregnancy-specific glucose tolerance disorder affecting patients who were not previously diabetic.

Hormonal changes during pregnancy induce insulin resistance. Imagine insulin as a key that allows glucose to enter the body’s cells. With gestational diabetes, this key works less effectively, preventing glucose from entering cells to be used as an energy source. As a result, sugar accumulates in the blood, leading to a rise in blood sugar levels.

What is the prevalence of gestational diabetes?

The prevalence of gestational diabetes in France is increasing. It rose from 10.8% in 2016 to 16.4% in 2021. This rise can be explained by various factors, including the aging of maternal age, the increase in overweight and obesity among women of childbearing age, as well as better diagnostic tools. Today, there are about 100,000 new cases of gestational diabetes developing each year.

Why undergo a blood glucose test to screen for gestational diabetes?

Screening for gestational diabetes is essential to prevent maternal and fetal complications. Fasting blood glucose (blood sugar level measured after a fasting period) is a key indicator for detecting hyperglycemia. An abnormally high sugar level can go unnoticed, as gestational diabetes is often asymptomatic.

By performing a blood glucose test, the physician can quickly identify patients requiring specific care. According to best practice recommendations, screening is recommended for at-risk pregnant women, as well as systematically between the 24th and 28th week of pregnancy.

The OGTT (Oral Glucose Tolerance Test) is the gold standard for diagnosing gestational diabetes. It involves measuring the blood glucose level while fasting, and then one and two hours after ingesting 75 g of sugar. The glycemic targets are specific:

• After 8 hours of fasting: it should be less than 0.92 g/L.
• One hour after glucose intake: below 1.80 g/L.
• Two hours later: less than 1.53 g/L.

This examination confirms the diagnosis of gestational diabetes and suggests an appropriate therapeutic approach, in accordance with the recommendations of the National College of Gynecologists, the Francophone Diabetes Society, and French Obstetricians.

What are the symptoms of gestational diabetes?

Gestational diabetes is often silent, making routine screening all the more important. However, certain signs may serve as warnings:

• Intense thirst and frequent urination: The body attempts to eliminate excess sugar through the kidneys.
• Unusual fatigue: Cells lack energy due to inefficient use of sugar.
• Blurred vision: Hyperglycemia can temporarily affect vision.
• Repeated infections: Especially urinary tract infections or candidiasis.

Obstetricians emphasize the importance of consulting as soon as these signs appear. However, these manifestations are not specific and may be attributed to the normal physiological changes of pregnancy.

What causes diabetes during pregnancy?

Gestational diabetes can lead to several complications during pregnancy. For the mother, it increases the risk of developing:

• Gestational hypertension.
• Pre-eclampsia, a serious condition characterized by high blood pressure accompanied by kidney impairment.
• An excess of amniotic fluid (hydramnios), which can lead to preterm delivery.
• Frequent urinary infections.

For the fetus, maternal hyperglycemia has significant implications:

• Excess sugar crosses the placenta, stimulating the fetal pancreas to produce more insulin.
• This fetal hyperinsulinemia promotes excessive growth, leading to macrosomia (weight over 4 kg).
• A high birth weight increases the likelihood of a difficult delivery, which may require a cesarean section.
• After birth, the newborn may experience metabolic disorders, such as neonatal hypoglycemia.

Children born to diabetic mothers also have an increased risk of developing type 2 diabetes later in life.

What are the risks of gestational diabetes for the baby?

Gestational diabetes can have several impacts on the baby:

• Fetal macrosomia: A high birth weight (> 4 kg) increases the risks of difficult delivery.
• Shoulder dystocia : A situation where the newborn’s shoulders become stuck after the head has emerged, constituting an obstetric emergency.
• Neonatal hypoglycemia: Due to excess insulin produced in response to maternal hyperglycemia.
• Respiratory distress: Pulmonary maturity sometimes delayed.
• Neonatal jaundice: Hyperbilirubinemia due to increased production of red blood cells.
• Increased risk of obesity and type 2 diabetes in adulthood.

These risks justify increased monitoring of the infant, as recommended by the best practice guidelines. Implementing preventive measures during pregnancy contributes to the child’s future health.

What are the signs of gestational diabetes?

In addition to the previously mentioned symptoms, certain clinical signs may indicate gestational diabetes:

• Excessive weight gain of the mother.
• High blood pressure.
• Glycemic alteration during analysis.
• Ultrasound revealing a fetus larger or heavier than normal for the gestational age.

Special attention should be given to patients exhibiting these symptoms, in order to implement appropriate screening and therapeutic management.

What are the causes of gestational diabetes?

Diabetes is primarily caused by hormonal changes during pregnancy that induce insulin resistance. Hormones produced by the placenta, such as placental lactogen, cortisol, and estrogens, decrease the effectiveness of insulin.

Several risk factors increase the likelihood of developing this condition:

• Overweight or obesity (BMI greater than 25).
• Advanced maternal age (over 35 years).
• Family history of type 2 diabetes.
• Personal history of gestational diabetes or pre-existing diabetes.
• Previous birth of a child weighing more than 4 kg.
• Glucose tolerance disorders identified before pregnancy.
• Ethnic origin (certain populations are at higher risk).

Understanding these causes allows pregnant women and healthcare professionals to take effective preventive measures.

How is gestational diabetes screening organized?

Screening for gestational diabetes is recommended for all at-risk patients and is conducted in several steps:

1. Fasting venous blood glucose as early as the first trimester for women with risk factors.
   • If it is higher than 0.92 g/L but lower than 1.20 g/L, an OGTT is prescribed.
   • If it is greater than or equal to 1.20 g/L, this indicates pre-existing diabetes.
2. Between the 24th and 28th week of pregnancy, a 75g OGTT is performed for all women not yet screened.
   • Measurement of fasting blood glucose levels, followed by one and two hours after ingestion of 75 g of glucose.
   • Diagnosis of gestational diabetes if at least one of the following values is met or exceeded:
     • Fasting: 0.92 g/L.
     • At 1 hour: 1.80 g/L.
     • At 2 hours: 1.53 g/L.

This research, in accordance with best practice guidelines, allows for early management to mitigate its consequences.

What is the normal blood sugar level for pregnant women?

In pregnant women, glycemic targets are stricter to protect the fetus:

• Fasting: blood glucose level below 0.92 g/L.
• One hour after a meal: less than 1.20 g/L.

It is recommended for patients with diabetes during pregnancy to perform blood glucose self-monitoring several times a day (typically 4 to 6 times). This practice ensures that glycemic targets are met and allows for real-time adjustments to insulin therapy.

What are the treatments for diabetes during pregnancy?

The treatment of gestational diabetes is based on lifestyle and dietary measures and, if necessary, on insulin therapy:

• Balanced diet :
  • Divide into 3 main meals and 2 to 3 snacks.
  • Favor complex carbohydrates with a low glycemic index.
  • Increase the intake of fiber.
  • Limit rapid sugars and saturated fats.
• Regular physical activity:
  • Engage in activities like walking, swimming, or prenatal yoga, for example
  • Exercise improves insulin sensitivity and helps control blood glucose levels.
• Blood glucose self-monitoring :
  • Measure blood glucose levels several times a day to adjust therapy if necessary.

If these measures are not sufficient, insulin therapy may be implemented after consultation with an endocrinologist-diabetologist. Oral antidiabetics are generally contraindicated during pregnancy.

What diet should a pregnant woman with diabetes follow?

In the case of diabetes during pregnancy, it is important to adopt an appropriate nutrition plan to control blood sugar levels:

• Divide food intake: 3 main meals and snacks to prevent glycemic spikes.
• Choose high-quality carbohydrates: Whole grains, legumes, green vegetables.
• Increase fiber: It slows down the absorption of sugar.
• Limit fast-acting sugars: Avoid sugary drinks, pastries, candies.
• Consume lean proteins: White meats, fish, eggs.
• Favor good fats: Vegetable oils rich in omega-3, nuts.
• Adequate hydration: Drink water regularly throughout the day.

A consultation with a dietitian allows for the establishment of a personalized meal plan, in accordance with best practice recommendations.

How is pregnancy monitored?

Monitoring a pregnancy with diabetes is multidisciplinary:

• Regular check-ups:
  • Monitored by the general practitioner, the gynecologist-obstetrician, and the endocrine-diabetologist.
  • Adjustment of treatment based on the results of self-monitoring of blood glucose.
• Additional ultrasounds:
  • Monitoring fetal growth.
  • Evaluation of amniotic fluid.
• Therapeutic education :
  • Learning how to manage diabetes.
  • Guidance on nutrition and regular activity.
• Special monitoring at the end of pregnancy:
  • Decision on the mode of delivery (vaginal birth or cesarean).
  • Prevention of complications during birth.

This close monitoring, in accordance with best practice guidelines, ensures optimal care for both the mother and child.

Why is it important to consult a doctor for gestational diabetes?

Consulting a doctor is essential for:

• Screen for diabetes early.
• Implement an appropriate management plan to prevent complications.
• Inform and support the patient throughout her pregnancy.
• Prevent the development of subsequent type 2 diabetes.
• Ensure postnatal follow-up for the mother and the child.