1ST CITY CLINICAL HOSPITAL

04/11/2024

Gestational diabetes mellitus (hereinafter referred to as GDM) or pregnancy diabetes is a disease in which blood sugar levels first increase during pregnancy and return to normal after childbirth. At the same time, the sugar numbers do not meet the criteria for “manifest” diabetes mellitus (DM).

Why does GDM occur?

Insulin is a hormone produced by the pancreas. Its purpose is to “drive” glucose into the cell to provide energy to the cell while maintaining normal blood sugar levels. Insulin works like a key that opens doors. The person ate - glucose was absorbed into the blood - the pancreas released insulin - insulin delivered glucose to the cells.

During pregnancy, this balance is disrupted. Insulin resistance increases every day - that is, the insensitivity of cells to insulin. There is enough insulin, he knocks on the cells to give them glucose, but no one opens the door for him. Accordingly, blood sugar rises. The main role in this process is played by the so-called contrainsular hormones: hormones produced by the placenta (placental lactogen and progesterone) and maternal hormones (cortisol, estrogens, prolactin), the concentration of which in the blood also increases with increasing pregnancy.

Insulin resistance is aggravated by an increase in the calorie content of the mother's food intake, a decrease in physical activity, and weight gain. The phrase that during pregnancy you have to eat for two is not just a myth, it is a dangerous myth.

With a hereditary predisposition to type 2 diabetes mellitus, in the presence of obesity, insulin secretion becomes insufficient to overcome insulin resistance, which leads to hyperglycemia (increased blood sugar levels). As a result of all of the above, the level of glucose in the blood of pregnant women increases.

High blood sugar during pregnancy negatively affects both the health of the woman herself and the condition of the fetus, and therefore requires timely diagnosis and subsequent correction.

Factors and risk groups for developing GDM.

1. Pregnancy itself is a risk factor for developing GDM.

2. The risk group includes pregnant women:

• overweight or obese (BMI (body mass index) above 25 kg/m2 - the risk doubles, above 30 - triples);
• with multiple pregnancy; - after IVF (in vitro fertilization);
• over 30 years old;
• with polycystic ovaries;
• with a large weight gain during real pregnancy;
• having close relatives with diabetes;
• with a burdened medical history in previous pregnancies - GDM, the birth of a child weighing over 4000 g, intrauterine fetal death.

Complications of pregnancy.

If GDM is not detected in a timely manner or the expectant mother does not take any action to treat it, then pregnancy complications such as: polyhydramnios (due to fetal polyuria and irritation of the amniotic sac with high concentrations of sugar, because sugar perfectly penetrates the placenta) develop much more often; - large size of the fetus (due to excess sugar in the fetus, fat is deposited in the chest and abdomen);

- intrauterine infection of the fetus (where there is a lot of sugar, bacteria will always appear there);

- the occurrence of diabetic fetopathy;

- preeclampsia - increased blood pressure, the appearance of protein in the urine;

- intrauterine fetal death.

In addition to all of the above, during childbirth the frequency of cesarean sections increases due to the large size of the fetus, and the risk of birth trauma for mother and child increases.

In the postpartum period, the risks are high:

- hypoglycemia (low blood sugar), and this is a risk of damage to the cardiovascular system and central nervous system of the newborn;

- breathing problems in a newborn. Why? Because maternal insulin does not penetrate the placenta, but glucose does easily. The baby's pancreas begins to secrete more insulin to absorb glucose and normalize the fetal sugar level. Hence the large size of the child. And after childbirth, there is no longer so much sugar, and the pancreas is accustomed to secreting a lot of insulin, which is where hypoglycemia often occurs in a newborn.

Are there long-term consequences of GDM for mother and child?

Of course they exist.

Diagnosis of GDM.

In most cases, GDM does not manifest itself with a clinical picture characteristic of the onset of diabetes mellitus, or the symptoms of hyperglycemia may be regarded by the patient as manifestations of pregnancy, for example, frequent urination. The physician should actively identify complaints associated with hyperglycemia.

Stage 1 - determination of venous plasma glucose on an empty stomach (after preliminary fasting for at least 8 hours and no more than 14 hours) when a pregnant woman first visits a doctor of any specialty (obstetrician-gynecologist, therapist, general practitioner) during pregnancy from 6 -7 to 24 weeks to exclude carbohydrate metabolism disorders. Glucose determination is carried out only in venous plasma. The use of personal glucometers to determine blood glucose is prohibited.

Stage 2 – conducting an oral glucose tolerance test (hereinafter referred to as OGTT) with 75 g of glucose. This study is a safe stress diagnostic test to detect carbohydrate metabolism disorders during pregnancy. Its implementation is recommended in the period of 24-28 weeks of pregnancy for all pregnant women without pregestational diabetes mellitus, who did not have a violation of carbohydrate metabolism in the first half of pregnancy.

The recommended optimal period for OGTT is 24–28 weeks, but it can be carried out up to 32 weeks of pregnancy (high risk of GDM, fetal size according to ultrasound tables ≥75th percentile, ultrasound signs of diabetic fetopathy, disproportionate fetal size), but not later. If signs of fetal macrosomia are detected by ultrasound (fetal size according to ultrasound tables ≥90th percentile) at 32 weeks and later, it is necessary to determine fasting venous plasma glucose.

OGTT is a safe stress diagnostic test.

During pregnancy, during OGTT, venous plasma glucose is determined: on an empty stomach, 1 and 2 hours after a glucose load.

Contraindications to OGTT:

• GDM/manifest diabetes mellitus diagnosed before 24 weeks of pregnancy;
• Malabsorption syndrome (resected stomach syndrome, bariatric surgery, dumping syndrome);
• Vomiting, nausea;
• Acute inflammatory or infectious disease;
• Exacerbation of diseases of the gastrointestinal tract;
• Strict bed rest in an inpatient due to obstetric complications (threat of miscarriage, cervical suturing, infusion of β2 adrenergic agonists, prevention of neonatal distress syndrome).

Rules for conducting an oral glucose tolerance test.

1. For 3 days before the test, you should follow your normal diet and exercise routine.
2. The evening before the test there should be a standard dinner. Last meal at 20.00-21.00
3. In the morning you need to be in the laboratory by 8.00, on an empty stomach, after an 8-12 hour fast. The first blood draw is performed on an empty stomach.
4. Then within 5-10 minutes you need to drink dissolved glucose (75 g of dry glucose powder per 250-300 ml of warm water). You can add the juice of half a lemon to the solution. Only glucose solution is used! You should not replace glucose with another sweet drink or food.
5. Repeated blood sampling is carried out 1 hour and 2 hours after taking glucose.
6. You cannot walk during the test. You need to sit comfortably.
7. Medicines that affect blood glucose levels (multivitamins, iron supplements (containing carbohydrates), glucocorticosteroids, beta-blockers, beta-adrenergic agonists), if possible, should be taken after the test.

If blood sugar levels exceed the norm on an empty stomach, after an hour or 2 hours, then a diagnosis of GDM is made. Next, the doctor will recommend a special diet, keeping a diary of self-monitoring of glucose levels on an empty stomach, an hour after meals and at night, and where the food consumed by the woman will be reflected. Thus, you will have to check your sugar level at least 5 times a day. Glucometers are quite suitable for these purposes. Or, today, there are more modern methods of monitoring blood glucose levels - a continuous glucose monitoring system. This is a miniature device that is installed on a woman. A woman installs a special application on her phone that allows her to see blood sugar levels. The device determines the blood sugar level every half hour for 5 days, and the woman sees the dynamics of the sugar level on her phone. This is a more accurate assessment method. In the 4th antenatal clinic, City Center “Extragenital Pathology and Pregnancy”, where pregnant women with GDM, insulin-dependent throughout the city of Minsk are observed, today, an endocrinologist, if indicated, installs this system.

Target glycemic levels for self-monitoring in GDM (blood plasma):

- on an empty stomach up to 5.1 mmol/l - 1 hour after a meal up to 6.7 mmol/l - 2 hours after a meal up to 6 mmol/l

If sugar levels return to normal within two weeks, then the pregnant woman remains on the diet. If sugars go beyond the “acceptable” limits, insulin will be prescribed.

Attention!

- insulin does not harm either the child or the mother, it is prescribed to maintain the full health of both mother and baby;

- insulin does not penetrate the placenta, but glucose, unlike insulin, passes unhindered and easily from mother to child;

- addiction to insulin does not develop;

- after childbirth, insulin is discontinued;

- any sugar-lowering pills are contraindicated during pregnancy!

Thus, the basic principles of treatment of GDM:

1. Diet;
2. Physical activity; 
3. If the previous 2 points are ineffective - insulin therapy.

What should a woman do after childbirth?

- consultation with an endocrinologist

- 2 months after birth, an OGTT with 75 g of glucose is recommended

- planning a subsequent pregnancy after consulting an endocrinologist

Diet. Principles of diet therapy:

1. Emphasis on the consumption of complex (slow) carbohydrates (up to 55% of the recommended daily caloric intake) with low fat content (25-30% of the recommended daily caloric intake). Complex (slow) carbohydrates - contain starch, fiber, pectin, glycogen (bread, legumes, cereals, pasta, potatoes, vegetables, cereals, nuts, herbs). They are slowly absorbed, give a feeling of fullness (starch + fiber), regulate intestinal function and support microflora (fiber).
2. A low-carbohydrate diet during pregnancy is NOT SUITABLE (a diet with a sharp restriction of carbohydrates in the diet to 40 g, increased consumption of protein and plant foods).
3. Calorie restriction (for overweight and obesity) of at least 1800 kcal/day.
4. The amount of fat should not exceed 30% of the daily calorie intake, while the consumption of saturated fats should be limited to 10%, and trans fats should be eliminated completely (trans fats are modified molecules that appear in unsaturated (vegetable) oils during repeated high-temperature processing).
5. The daily amount of fiber should be at least 28 g. Fiber (dietary fiber) is a type of complex carbohydrates in plant products. Fiber forms the structure of vegetables and is also a material for the coating of grains. There is a lot of dietary fiber in bran, cereals, grains, nuts, and any vegetables and fruits. The advantage of fiber products is their low glycemic index (GI).
6. To prevent the appearance of ketone bodies, the break between dinner and breakfast should be no more than 10 hours.
7. Each meal should contain slowly digestible carbohydrates, protein

General recommendations:

- eat 4-5 times a day (eating a large amount of food at one time provokes a rise in blood sugar), limit food portions.

- carbohydrates (cereals, bread, pasta, fruits, berries, some types of vegetables, liquid fermented milk products) cannot be completely excluded from the diet. Preference should be given to grains, vegetables and permitted fruits, refusing sweet, fatty, and salty foods.

- slow carbohydrates should be consumed with every main meal (breakfast, lunch, dinner).

- completely eliminate ready-made breakfasts (muesli, cereal, fitness bars, instant cereals (3-10 minutes), protein shakes, semolina porridge, white refined rice).

- products in the “For diabetics” section are not suitable during pregnancy.

- exclude any sugar (white, brown, cane, refined sugar, coconut).

- exclude white flour and products made from it, replace with whole grain.

- exclude bananas, grapes, persimmons, cherries, watermelon, melon from the diet, replace them with non-sweet apples, hard pears, kiwi, and citrus fruits.

- exclude fruit juices, freshly squeezed juices, milkshakes, canned fruits, preserves, honey, jams from the diet.

- starch-containing products should be no more than 100 g per serving (rice, wheat, corn, potatoes, sweet potatoes, legumes, bread, pancakes, noodles, pasta, porridge, jelly).

- allowed fruits 100 g (maximum 150 g) per serving.

- all low-fat and low-fat dairy and fermented milk products, as a rule, contain starch (simple fast carbohydrate), so it is necessary to replace them with products with a normal percentage of fat content (5%-7%).

- replace baked goods and sweets (confectionery with trans fats) with dark chocolate (more than 75% cocoa) 25-30 g per day.

- limit consumption of red meat. - completely exclude sausages, sausages, carbonates, ham from the diet

- the best culinary processing of products - steaming, boiling, stewing, baking “in the sleeve”.

- obtain the required amount of fat from the right animal and plant products (meat and dairy products from free-range cows, wild fish, eggs, cheese, cottage cheese, butter, nuts, legumes, olive oil, cold-pressed vegetable oils).

- It is recommended to drink 1-1.5 liters of liquid per day.

- choose foods high in fiber. Fiber (or dietary fiber) stimulates the intestines and slows down the absorption of excess sugar and fat into the blood. In addition, foods rich in fiber contain large amounts of vitamins and minerals.

High fiber foods:

- Bread and products made from whole grain flour.

- Whole grain cereals (all gray and brown cereals - rolled oats, oatmeal, buckwheat, barley, pearl barley, bulgur, spelt, flaxseed porridge, rice - wild, brown, red, brown).

- Pasta made from durum wheat.

- Frozen and fresh vegetables, herbs, mushrooms, herbs.

Vegetables that can be eaten without restrictions are zucchini, zucchini, cucumbers, spinach, green beans, radishes, asparagus, broccoli, cauliflower, greens, celery, lettuce.

These foods are low in calories and low in carbohydrates. They can be eaten at main meals and when you feel hungry. It is better to consume these products raw (salads), steamed or boiled.

Vegetables that need to be limited are potatoes, boiled/stewed beets, carrots, pumpkin, peas, corn.

What does the presence of acetone (ketone bodies) in urine indicate: 

1. Low carbohydrate diet.

- carbohydrates in the daily amount should be at least 45%, they are the main source of energy.

- if you reduce the consumption of carbohydrates, then in order to provide the cell with energy, fats will begin to break down and ketone bodies will appear in the urine.

- if ketone bodies appear in the urine, it is necessary to review the diet in the direction of increasing the amount of slow carbohydrates.

     2. НInsufficient amount of fluid drunk (less than 1 liter per day).

     3. Prolonged fasting for more than 10 hours.

     4. Prolonged physical activity.

Glycemic index (GI)

      Glycemic index (GI ) is an indicator of the speed at which carbohydrates are absorbed and the ability of different foods to increase blood glucose levels. High GI foods contribute to a rapid increase in blood glucose levels. Low GI foods are digested more slowly, gradually releasing energy.

- the fewer carbohydrates in a product, the lower the glycemic index (GI).         

  - high GI - above 70 units

                  - average GI - 40-70 units

                  - average GI - 40-70 units

How to lower the glycemic index (GI)

- the more fiber a food, including various foods, contains, the lower the total GI will be.

- raw vegetables and fruits have a lower GI than heat-treated ones (raw carrots - GI = 35, boiled - GI = 85).

- mashed potatoes have a higher GI than boiled potatoes. This is due to different degrees of “denaturation” of starch during the cooking process of potatoes. In general, excessive cooking of any products containing starch (pasta, cereals) increases their GI.

- the combination of proteins with carbohydrates reduces the overall GI. On the one hand, proteins slow down the absorption of carbohydrates into the blood, and on the other hand, the very presence of carbohydrates contributes to better digestibility of proteins.

- the more the product is crushed, the higher its GI. This mainly applies to grains. Whole buckwheat and crushed buckwheat have different GIs.

- adding a very small amount of fat to carbohydrates lengthens the time of their absorption and thereby reduces the GI.

- the longer food is chewed, the slower carbohydrates are absorbed.