A glucose tolerance test during pregnancy is an important test that allows you to identify gestational diabetes mellitus. Although in most cases it goes away on its own after delivery, disturbances in carbohydrate metabolism pose a danger to the mother and fetus. It is a risk factor for obesity and also a cause of adverse pregnancy outcomes. Timely detection of pathology and initiation of insulin therapy can prevent Negative consequences gestational diabetes mellitus.

Why is a glucose tolerance test done during pregnancy?

A glucose test during pregnancy is done in order to timely identify gestational diabetes mellitus and carry out treatment. It is administered to those women who did not have carbohydrate metabolism disorders in the early stages, when they donated blood for glucose on an empty stomach.

The test is not done only in the following cases:

• previously diagnosed diabetes mellitus;
• glucose intolerance;
• diseases of the intestines or stomach, in which glucose is not absorbed.

Everyone else gets tested. If a woman has an acute infection, bed rest or early toxicosis, the study may be delayed for several weeks.

Principles for diagnosing diabetes in pregnant women

Gestational diabetes mellitus is a disease characterized by newly diagnosed glycemia ( higher level blood glucose) during pregnancy. The diagnosis is made if the glycemic level does not meet the criteria for overt diabetes.

In pregnant women, diagnosis is carried out in 2 stages. When first contacting an obstetrician-gynecologist at gestational age up to 24 weeks, all women without exception are screened. They pass at stage 1:

• venous blood to determine fasting glucose in it;
• or blood sugar test at any time of the day, regardless of food intake;
• or blood for glycated hemoglobin (this is an indicator reflecting the state of carbohydrate metabolism over the past few months).

In the future it is possible various options development of events, depending on the established blood sugar level. If values ​​corresponding to manifest (not gestational!) diabetes mellitus are detected, the woman is immediately referred to an endocrinologist for further management. He conducts additional tests to clarify the type of disease. They are radically different. In type 1 diabetes, the pathology is associated with impaired insulin formation. In the second, the disease is caused by tissue resistance (insensitivity) to this hormone. That is, insulin is produced, but the cells “do not see it.”

Type 1 or 2 diabetes in a pregnant woman is suspected if the glucose level at any time of the day exceeds 11.1 mmol per liter. In this case, a clarifying study is carried out. The patient donates blood on an empty stomach. If in venous blood it exceeds 7 mmol per liter, this indicates that the woman has diabetes. It is in this case that the endocrinologist deals with its further management. But there are also borderline situations. Sometimes the sugar level is higher than normal. But not so high that overt diabetes can be diagnosed. If the fasting level exceeds 5.1 mmol per L, but does not reach 7.0, then gestational diabetes is diagnosed. To confirm this diagnosis, a second stage of diagnosis is required. Namely, conducting a glucose tolerance test.

Is a glucose tolerance test done in the absence of hyperglycemia?

We have already found out that this diagnostic test is mandatory in cases where there are borderline results from a previous study. That is, if fasting blood glucose is higher than normal, but does not reach the level when manifest diabetes mellitus can be diagnosed.

But some women need to get tested even in the absence of fasting hyperglycemia. That is, if sugar levels are below 5.1 mmol per liter. This need is associated with the presence of one or more risk factors from the following:

• the presence of at least 1 degree obesity in a woman before conceiving a child (corresponds to a body mass index of over 30 kg per square meter);
• medical history: type 2 diabetes in 2 or more immediate relatives (these are considered mother, father, brothers and sisters, as well as children);
• disorders of carbohydrate metabolism that were diagnosed during a previous pregnancy (including if metabolic processes were completely normalized after the birth of the child);
• determination of glucose in the urine (indicates that the sugar level is very high, since the renal threshold for its concentration in the blood has been exceeded - with a low level of glucose, it never appears in the urine).

All women who have at least one of these factors are included in the group high risk for gestational diabetes mellitus. This means that they need to be examined, regardless of the results of the first stage of diagnostic procedures.

Underexamination and overdiagnosis

A two-stage examination of women for indicators of carbohydrate metabolism is necessary in order to avoid:

• underexamination - when a woman is not diagnosed with existing gestational or manifest diabetes mellitus, she will not receive treatment, and this threatens the normal course of pregnancy and can provoke complications in the fetus;
• overdiagnosis - when a woman who has normal indicators of carbohydrate metabolism is mistakenly diagnosed with signs of a disorder, and this leads to the establishment of a non-existent diagnosis.

The consequences of under-examination are much worse than over-diagnosis. Because with undetected diabetes, complications develop. Many of them are dangerous. Some even pose a threat to the life of the mother and her child.

At the same time, the consequences of overdiagnosis are not so sad. If a woman is misdiagnosed, treatment is initial stage includes a diet, increased physical activity. Naturally, such methods of therapy have never harmed anyone. Such treatment will not lead to hypoglycemia and associated complications.

Gestational diabetes mellitus is sometimes treated with insulin. In this case, hypoglycemia is indeed possible. However, it is unlikely, because during the treatment of pregnant women, carbohydrate metabolism indicators are constantly monitored. Fasting glucose tests are performed and glycated hemoglobin tests are taken. Therefore, even in the case of overdiagnosis and misdiagnosis Doctors will quickly find out that the woman does not have diabetes. Then the treatment will be stopped.

To avoid underexamination, if the blood test results are borderline, the doctor may ask the woman to retake the tests. Recent studies have shown that when the same blood samples are tested in different laboratories, the spread of results averages 8.7%. In practice, this means that one laboratory may give you a reading of 5.5 mmol per liter, which is an indication for a glucose tolerance test. In another laboratory, the result may be 5.0 mmol, which is not a basis for further in-depth examination of the woman, because it falls within the normal range.

The test results are also influenced by various external and internal factors. This is taking medications, taking them the night before the examination is too large quantity food, alcohol, or vice versa, a long period fasting. Smoking or short-term stress can have an effect. Therefore, if the test results are close to borderline, the doctor may evaluate them as doubtful and ask the woman to donate blood again.

Preparing for a glucose tolerance test during pregnancy

The study is carried out only on an empty stomach. The fasting period should be at least 8 hours. But it is desirable that it also does not exceed 14 hours. Therefore, you should not refuse dinner the evening before the test. But under no circumstances should you have breakfast before going to the doctor.

One day before the glucose tolerance test, you should not drink alcohol during pregnancy. You need to eat as usual. You should not try to “cheat” the test results by giving up carbohydrates or adjusting your diet in any other way. Remember that you are taking tests not for the doctor, but for yourself. Timely detection of diabetes mellitus or metabolic syndrome is important for successful treatment.

Prohibited the day before the study:

• become physically overtired;
• exercise;
• fast for a long time;
• overeat.

It should be borne in mind that many drugs distort test results. Because some medications lower blood glucose levels, others increase them. If possible, you should stop taking any medications a few days before the diagnosis. Except for those that are vital. If you are in doubt about which medications are required and which are not, consult your doctor.

Danger to the fetus of a glucose tolerance test during pregnancy

There are many myths and unfounded fears among women about this analysis. There are rumors that during pregnancy glucose tolerance test may harm the baby or cause diabetes in the mother.

None of this is true. The test is safe. Because during the research, the woman drinks a sugar solution, not poison. And her blood is taken from the cubital vein, and not from the baby’s umbilical cord. So the study does not carry any risks.

But it is necessary to conduct a test up to 32 weeks. In the vast majority of cases, it is done between 24 and 26 weeks. It is allowed to carry out up to 28 weeks inclusive. According to indications, it can be performed from 29 to 32 weeks if:

• the woman has a high risk of gestational diabetes mellitus;
• too much big sizes fetuses that do not correspond to the gestational age;
• Ultrasound signs of diabetic fetopathy are observed.

How is a GTG test done during pregnancy?

From a woman on an empty stomach, blood is taken from a vein into a cold test tube. It must contain enolase inhibitors to prevent spontaneous glycolysis, as well as anticoagulants to prevent the blood from clotting. The tube may also contain preservatives. She is placed in the cold. Centrifuge for 30 minutes to separate the formed elements. The result is plasma - the liquid part of blood. Glucose is determined in it.

Determination of glucose levels is carried out only in the laboratory. Portable glucose meters are not used for this purpose.

Within 5 minutes, the woman drinks a solution containing 75 g of glucose. It is dissolved in 250 ml of water. The first sip is considered the beginning of the test.

Next, blood is taken after 1 hour and after 2 hours. Thus, a pregnant woman takes this test three times in total. But the study may be interrupted at any stage if diabetes is diagnosed. Including after the first blood draw - even before taking 75 g of glucose.

Glucose test standards during pregnancy

Blood from a vein is taken three times during the test. The first time - on an empty stomach. Then - after 1 and 2 hours. The norms for pregnant women are somewhat different from the generally accepted ones. Gestational diabetes is diagnosed if:

• fasting glucose more than 7 mmol/l;
• an hour after the load it is more than 10 mmol/l;
• after 2 hours the value exceeds 8.5 mmol/l.

Normally, glucose should not circulate in the blood long time after meal. Insulin should be released immediately. After this, the sugar moves inside the cells. Therefore, it is no longer detected in elevated levels in the blood. But this does not happen in the case of diabetes. The absorption of glucose by tissues is impaired. Therefore, sugar remains in the blood in large quantities.

If the glucose tolerance test deviates from the norm during pregnancy, the woman is prescribed treatment. She receives insulin medications, which help normalize carbohydrate metabolism, preventing undesirable consequences gestational diabetes mellitus for the mother and her child.

Why is a glucose tolerance test necessary?

An oral glucose tolerance test (OGTT), or glucose tolerance test, can detect carbohydrate metabolism disorders during pregnancy, that is, check how well the body regulates sugar levels. This test determines the presence of pregnancy-related high levels of glucose (sugar) in the blood.

Gestational diabetes can develop even in women who are not at risk, since pregnancy itself is a significant risk factor for carbohydrate metabolism disorders.

Gestational diabetes usually has no noticeable symptoms, so it is important to get tested in time so as not to miss the disease, since without treatment, GDM can have serious consequences for both mother and baby.

An OGTT with 75 g of glucose is performed for all pregnant women between 24 and 28 weeks of pregnancy (24-26 weeks is considered optimal).

How is carbohydrate metabolism disorder diagnosed during pregnancy?

Stage 1. When a pregnant woman first visits a doctor up to 24 weeks, the level of fasting venous plasma glucose is assessed:

• result
• with a fasting venous plasma glucose level of 5.1 mmol/L (92 mg/dL), but
• with fasting venous plasma glucose levels? 7.0 mmol/l (126 mg/dl) a preliminary diagnosis of manifest (newly diagnosed) diabetes mellitus (DM) is established.

Stage 2. All women who have not been diagnosed with carbohydrate metabolism disorders in early pregnancy undergo an OGTT with 75 g of glucose between 24 and 28 weeks of pregnancy.

Is it necessary to prepare specially for the glucose tolerance test?

The glucose tolerance test is performed against the background regular food containing at least 150 g of carbohydrates per day for at least 3 days before the test. If you follow any diets, diabetes may simply not be detected, even if it is present.

The test is performed in the morning on an empty stomach after an 8-14 hour overnight fast. Drinking water is not prohibited. The day before the test, avoid alcohol. Smoking is prohibited until the test is completed. If possible, until the end of the test, refrain from taking medications that affect blood glucose levels (multivitamins and iron supplements containing carbohydrates, glucocorticoids, beta-blockers, etc.).

Glucose tolerance test is not performed:

• at early toxicosis(nausea, vomiting);
• against the background of acute inflammatory or infectious diseases;
• with exacerbation of chronic pancreatitis or the presence of dumping syndrome;
• if necessary, strict bed rest (the test can be performed after dilation motor mode).

How is a glucose tolerance test performed?

You must sit during the entire test. Physical activity (even walking) can affect the test result. An OGTT uses a blood sample from a vein. The use of glucometers is prohibited.

Stage 1. A venous blood plasma sample is taken and glucose levels are measured. If the result is outside the normal range (? 5.1 mmol/l), the test is stopped and the fact is established gestational diabetes(or manifest DM). If the glucose level cannot be determined immediately, the test is continued and completed.

Stage 2. After taking blood, the pregnant woman must drink a glucose solution within 5 minutes, which consists of 75 g of dry glucose dissolved in 250-300 ml warm water(when using glucose monohydrate, 82.5 g of substance is required). The start of taking the glucose solution is considered the start of the test. Glucose solution is a very sweet drink. It may cause nausea or even vomiting in some pregnant women. There is no need to try to drink the glucose solution in one gulp. To make the drink less cloying, you can squeeze a little lemon juice into it.

Stage 3. 1 and 2 hours after the glucose load, the following venous plasma samples are taken to determine the glucose level (blood collection is allowed only after 2 hours). If the blood test taken after 1 hour reveals gestational diabetes, the test is stopped.

IN exceptional cases OGTT with 75 g of glucose is possible up to 32 weeks of pregnancy.

What blood glucose level indicates gestational diabetes?

(criteria for diagnosis of GDM in Lately were tightened, since increased blood sugar during pregnancy has an extremely negative effect on the child)

* the indicated threshold values ​​are based on the results of the NARO study (2000-2006) and last years accepted in a number of developed countries (USA, Japan, Germany, Israel, etc.)

According to the results of an OGTT with 75 g of glucose, to establish a diagnosis of gestational diabetes, it is sufficient that at least one of the three glucose levels is equal to or above the threshold. That is, if fasting glucose is ?5.1, glucose loading is not carried out; if at the second point (after 1 hour) glucose is 10.0, then the test is stopped and the diagnosis of GDM is established.

Often in clinics they carry out the so-called “breakfast test”: they ask a pregnant woman to donate blood (usually from a finger), then they send her to eat something sweet and ask her to come again after some time to donate blood. With this approach, there cannot be generally accepted threshold values, because everyone’s breakfasts are different, and it is impossible to exclude the presence of gestational diabetes based on the results obtained.

Is a glucose tolerance test dangerous?

A solution of 75 g of anhydrous glucose can be compared to a breakfast consisting of a donut with jam. That is, OGTT is a safe test for detecting carbohydrate metabolism disorders during pregnancy. Accordingly, the test cannot provoke diabetes mellitus.

Refusal to test, on the contrary, can have serious consequences for both mother and child, since it will not be detected and appropriate measures will not be taken to normalize blood glucose levels.

The glucose tolerance test (GTT) is one of the methods for diagnosing diabetes mellitus and is part of a set of studies recommended during pregnancy. With the help of a simple analysis, you can detect an increase in blood sugar and detect dangerous pathology before complications develop. Diagnosis is carried out from 24 to 32 weeks of pregnancy. The results obtained make it possible to assess the level of glycemia and draw conclusions about the state of carbohydrate metabolism in the body.

Indications for performing a glucose tolerance test in pregnant women

• Metabolic syndrome (metabolic disorder associated with decreased tissue sensitivity to insulin).
• Excess body weight.
• Gestational diabetes in a previous pregnancy.
• Family history of diabetes mellitus.
• Adverse obstetric history: birth of a child weighing over 4 kg, unexplained death of a newborn, stillbirth.
• Premature birth in the past.
• Repeated or persistent infection urinary tract, skin.
• The pregnant woman is over 35 years old.
• Nationality: representatives of nations Far North have an increased tendency to metabolic disorders.

Gestational diabetes mellitus, or why it is important to monitor your blood glucose levels

Gestational diabetes mellitus (GDM) is a disorder of glucose metabolism that occurs during pregnancy. This is a temporary condition, and after the baby is born, glucose levels return to normal. IN in rare cases GDM provokes the development of true diabetes mellitus outside of gestation.

Gestational diabetes does not affect the woman’s condition, but threatens the development of serious problems with the fetus:

• Spontaneous miscarriage (mostly at 6-12 weeks).
• Premature birth (after 22 weeks).
• Impaired microcirculation in the placenta and the development of placental insufficiency.
• Chronic fetal hypoxia, developmental delay.
• Premature detachment of a normally located placenta and bleeding, threatening the life of the woman and the fetus.
• Preeclampsia is a complication of pregnancy accompanied by hypertension and edema.
• Polyhydramnios.
• Diabetic fetopathy: child weight more than 4 kg at birth, hypoglycemia, neurological disorders.

The best prevention of such complications is the timely detection of gestational diabetes using a glucose tolerance test.

Contraindications

A glucose tolerance test is not performed in the following conditions:

• diagnosed diabetes mellitus before pregnancy;
• pregnancy period is more than 32 weeks;
• toxicosis of early pregnancy with nausea and vomiting;
• acute viral infections;
• diseases of the pancreas (acute process or chronic pathology in the acute stage);
• condition after removal of the stomach or small intestine;
• severe liver pathology;
• other gastrointestinal diseases in the acute stage.

Stages of performing a glucose tolerance test

GTT is performed in two versions:

• oral - a woman takes a glucose solution orally;
• intravenous - the drug is injected into a peripheral vein.

During pregnancy, oral GTT is mainly used.

Diagnosis of gestational diabetes is carried out in two stages: screening and the GTT itself. A screening test is an assessment of blood sugar. The analysis is taken on an empty stomach from a vein. All women take a glucose test, regardless of medical history and the presence of complaints when they first see a doctor. Further tactics will depend on the results of the analysis:

• If the glucose level is equal to or greater than 7 mmol/L, no other tests are performed. The woman is sent for a consultation with an endocrinologist for observation and treatment for diagnosed diabetes mellitus.
• If the glucose concentration is outside the normal range, but does not reach the limit established for diabetes mellitus (5.5-7 mmol/l), they speak of impaired glucose tolerance. This condition is a direct indication for performing GTT.
• At normal level glycemia, GTT is also indicated for women at high risk for developing diabetes mellitus.

Preparing for the examination

To obtain the correct results, a woman must follow all the doctor’s recommendations:

• The blood test is taken strictly on an empty stomach in the first half of the day from 7 to 11 o’clock.
• You should not eat on the morning of the examination. You can drink plain water.
• The last meal should be 8-14 hours before the test.
• Three days before the test, you should stick to your usual diet without limiting carbohydrates (up to 150 g per day). The last meal should contain at least 50 g of carbohydrates.
• For three days before the test, you need to exclude factors that can affect glucose levels: dehydration, stress, heavy physical activity, acute intestinal infections with vomiting and diarrhea.
• Before the test, it is not recommended to take medications that affect glucose concentration: iron supplements, multivitamin complexes, corticosteroids, etc. This issue should be discussed with your doctor.

Technique for performing a glucose tolerance test

The examination takes place in four stages:

• Stage No. 1. Venous blood is collected on an empty stomach and immediately assessed. If the glucose concentration exceeds 5.1 mmol/l, the study is completed and a diagnosis of “manifest diabetes mellitus” or “gestational diabetes mellitus” is made. In other situations, the woman moves on to the second stage.
• Stage No. 2. A pregnant woman receives a glucose solution (75 g of dry matter per 200 ml of warm water). The solution must be drunk entirely within 5 minutes. You cannot drink the whole water; you must take small and approximately equal sips. Next, for an hour the patient should be in a comfortable position - sitting or lying down.
• Stage No. 3. An hour after the woman has taken the glucose solution, blood is drawn from a vein. If the sugar concentration exceeds 5.1 mmol/l, the test is stopped.
• Stage No. 4. This is carried out only if at the third stage the glucose concentration remains below 5.1 mmol/l. An hour later, blood is taken again and the glycemic level is determined. All data is entered into a form indicating the time of receipt.

Decoding the results

Blood glucose values ​​during GTT are presented in the table:

All results are written out on a form and reflected on the sugar curve. Normally healthy person There is an increase in glucose an hour after the carbohydrate load, but not more than 10 mmol/l. Over the next hour, there is a gradual decrease in blood sugar levels. Exceeding the threshold values ​​indicates the development of gestational diabetes mellitus.

Important aspects

Nuances that you should know when taking a glucose tolerance test:

• Screening dates for taking the test are from 24 to 28 weeks. According to indications, the analysis can be performed up to 32 weeks of pregnancy. After 32 weeks, GTT is not performed due to the high risk of complications.
• Only venous blood is taken for the study. Capillary blood test results may be unreliable.
• The established norms do not change depending on the stage of pregnancy.
• If controversial results are obtained, the test should be repeated after two weeks, eliminating all factors that could affect glucose levels.

Gestational diabetes is not a death sentence. After the baby is born, the glucose tolerance test is repeated. If the sugar level returns to normal, the diagnosis is removed. When the glucose concentration remains high after exercise, true diabetes mellitus is said to be manifesting.

Description

Determination method Hexokinase.

Material under study See description

Gestational diabetes mellitus or diabetes mellitus of pregnancy is a disorder of glucose tolerance that occurs or is first detected during pregnancy. The pathology affects an average of 7% of pregnant women (estimates range from 1-14% depending on the population studied and the criteria applied). This disorder does not meet the criteria for overt diabetes, but represents a serious medical problem because it is associated with an increased incidence of pregnancy complications (for mother and fetus), as well as an increased risk of developing type 2 diabetes in a woman in the future.

Pregnancy is characterized by increased insulin resistance, a compensatory increase in insulin secretion, and hyperinsulinemia. IN early period pregnancy (first trimester and first half of the second trimester), blood glucose on an empty stomach and after meals in pregnant women is slightly lower than in non-pregnant women. Insulin resistance usually occurs in the second trimester and worsens throughout pregnancy. The physiological meaning of this phenomenon is to guarantee an adequate supply of glucose to the fetus; its mechanism is largely related to the influence of hormones secreted by the placenta. In gestational diabetes, changes in insulin resistance are significantly more pronounced than in normal pregnancy, while the compensatory increase in insulin secretion is also disrupted.

To screen for diabetes in pregnant women, it is recommended to conduct a blood glucose or glycated hemoglobin (HbA1c) test when a pregnant woman first consults a doctor for up to 24 weeks. These studies make it possible to identify manifest (overt) diabetes mellitus using one of its criteria: fasting glucose above 7 mmol/l (or in a random sample above 11.1 mmol/l) or HbA1c above 6.5%; or include the pregnant woman in the group of probable gestational diabetes (criterion - fasting glucose above 5.1, but below 7.0 mmol/l). Before 24 weeks of pregnancy, a glucose tolerance test is recommended only for pregnant women with high risk factors for gestational diabetes but normal fasting glucose screening test values. These factors: 1) obesity - body mass index before pregnancy >30 kg/m2; 2) type 2 diabetes mellitus in close relatives; 3) any disorders of carbohydrate metabolism in the past - gestational diabetes in a previous pregnancy, impaired glucose tolerance, changes in fasting blood glucose levels; 4) detection of glucose in urine.

All other pregnant women (who have not had diabetes mellitus detected by preliminary glucose screening tests) are recommended, unless there are contraindications, to undergo a glucose tolerance test to screen for gestational diabetes between 24 and 28 weeks of pregnancy. In exceptional cases, GTT with 75 g of glucose can be carried out up to 32 weeks of pregnancy. Carrying out GTT with 75 g of glucose for more later may be dangerous for the fetus!

Directly at INVITRO medical offices, the glucose tolerance test procedure for pregnant women is carried out during pregnancy up to 28 weeks + 0 days on the date of blood collection.

The glucose tolerance test is not performed in the following situations:

• with early toxicosis of pregnancy (vomiting, nausea);
• if it is necessary to adhere to strict bed rest (the test is not carried out until the motor mode is expanded);
• against the background of acute inflammatory or infectious disease;
• with exacerbation of chronic pancreatitis or the presence of dumping syndrome (resected stomach syndrome).

If the fasting glucose level is 7 mmol/L or higher, an exercise test is not performed. In INVITRO medical offices, a preliminary measurement of blood glucose levels is carried out using a finger prick using the dry chemistry method using a reagent strip. If the result is above 7.5 mmol/l, a stress test is not performed; it is recommended to perform a glucose test from venous blood on an empty stomach without stress.

During the test, the patient must drink a glucose solution within 5 minutes, consisting of 75 g of dry glucose dissolved in 250–300 ml of warm (37–40 ° C) drinking still water. The time is counted from the start of taking the glucose solution. Venous blood is taken three times for testing:

1. on an empty stomach (before taking glucose),
2. 1 hour after taking glucose,
3. 2 hours after taking glucose.

Material for research:

• in all other situations - plasma (EDTA, fluoride, tube with a gray cap).

Literature

1. Dedov I.I., Krasnopolsky V.I., Sukhikh G.T. Russian national consensus "Gestational diabetes mellitus: diagnosis, treatment, postpartum care." - Diabetes. 2012, no. 4, pp. 4-10. http://dmjournal.ru/ru/articles/catalog/2012_4/2012_4_4
2. Diagnostic criteria and classification of hyperglycaemia first detected in pregnancy. World Health Organization 2013. WHO/NMH/MND/13.2.
3. http://www.who.int/diabetes/publications
   Hyperglycaemia_In_Pregnancy/en/index.html
   Standards of Medical Care in Diabetes - 2013. American Diabetes Association. – Diabetes Care, 2013, Vol.36, Suppl. 1, S11-S66.
4. http://care.diabetesjournals.org/content/36/
   Supplement_1/S11.full.pdf+html

Preparation

Strictly on an empty stomach (from 7.00 to 11.00) after an overnight fasting period of 8 to 14 hours.

• The recommended period for performing GTB is 24-28 weeks of pregnancy; the test can be performed at earlier stages of pregnancy if there is a corresponding doctor’s instructions.
• To conduct GTB-S, the patient must have a referral from the attending physician or medical consultant of the Moscow Region / Medical Center indicating the date of issue, the doctor’s full name and his personal signature. During the 3 days preceding the day of the procedure, the patient must: stick to a regular diet without limiting carbohydrates; exclude factors that can cause dehydration (insufficient drinking regime
• refrain from taking medications, the use of which may affect the results of the study (salicylates, oral contraceptives, thiazides, corticosteroids, phenothiazine, lithium, metapyrone, vitamin “C”, etc.).
• Pregnant patients medicines that affect blood glucose levels (multivitamins and iron supplements containing carbohydrates, glucocorticoids, β-blockers, β-adrenergic agonists), if possible, should be taken after the end of the test.

ATTENTION!!! Cancellation of medications is carried out only after preliminary consultation of the patient with a doctor!

Indications for use

• screening examination of pregnant women to detect gestational diabetes at 24-28 weeks of pregnancy;
• screening examination of pregnant women up to 24 weeks in the presence of high-risk factors for gestational diabetes.

Interpretation of results

Interpretation of research results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. The doctor makes an accurate diagnosis using both the results of this examination and the necessary information from other sources: medical history, results of other examinations, etc.

Units of measurement and conversion factors:

Units of measurement in INVITRO - mmol/l

Alternative units: mg/dL

Unit conversion: mg/dL *0.0555=>mmol/l

Interpretation of the result:

Previously used criteria

WHO criteria ( World Organization Health), 2006: when using a 2-hour version of the load test (glucose 75 g) and two blood draws (on an empty stomach and 2 hours after exercise), the laboratory criterion for gestational diabetes was considered to be exceeding at least one of the threshold glucose levels - above 7 mmol/ l on an empty stomach or above 7.8 mmol/l 2 hours after exercise. New criteria

An international multicenter study examining the relationship between hyperglycemia and adverse pregnancy outcomes (HAPO Study - Hyperglycemia and Adverse Pregnancy Outcomes), conducted in 2000–2006, showed that the previously used criteria for diagnosing gestational diabetes mellitus require revision. Based on the findings of this study, new criteria for diagnosing gestational diabetes were proposed, which are currently supported by WHO, ADA (American Diabetes Association), as well as the consensus opinion of experts from the Russian Association of Endocrinologists and experts from the Russian Association of Obstetricians and Gynecologists, set out in the Russian National consensus “Gestational diabetes mellitus: diagnosis, treatment, postpartum care” (2012). These recommendations are shown in the table (exceeding any of 3 thresholds - fasting, 1 hour or 2 hours after exercise is considered as a laboratory criterion for gestational diabetes).

Threshold values ​​of venous blood glucose for the diagnosis of gestational diabetes when performing a glucose tolerance test with 75 g of glucose.

Procreation is one of the natural laws inherent in every person. At the same time, bearing a child involves increased stress on all vital systems and organs of the expectant mother. It is very important to monitor the development of this condition, carry out necessary research, correction and timely treatment emerging pathologies.

Purpose of ordering a tolerance test

A glucose tolerance test is recommended taking into account the fact that a hyperglycemic state is rarely accompanied by complaints and manifestations, but poses a certain danger to the mother and developing child. Optimal time it is carried out in the third trimester of pregnancy, after 24 weeks (no later than 32 weeks).

note

This type of research must also be carried out due to the fact that about 10-15% of pregnant women have a predisposition to latent (hidden) diabetes.

There are certain indications for this:

• presence of pregnant women in relatives;
• fetal diseases detected in utero;
• pathologies of past pregnancies (, large fruit, gestational diabetes, stillbirth);
• and nutritional obesity;
• excessive weight gain;
• previously existing increased amount sugar in the blood and/or urine.

If these problems are present, it makes sense to conduct a glucose tolerance test from 10 to 16 weeks of pregnancy. Some experts prescribe it even earlier, but there are no objective grounds for this. At normal indicators The study is repeated after 24 weeks.

How to take a glucose tolerance test during pregnancy

The analysis is carried out according to the direction of the attending physician. 3 days before it is performed, you should refrain from eating fatty and fried foods, and do not consume smoked meats, cakes, or coffee.

It would be better to limit (but not exclude!) flour and salty foods. That is, the diet should be neutral. Drinking alcohol and smoking are strictly prohibited (unfortunately, some pregnant women allow themselves to do this).

• Analysis values ​​may be influenced by:
• preparations containing;
• corticosteroid hormones;
• multivitamins;
• medications that lower blood pressure (in particular beta-blockers);
• psychotropic medications;

a number of diuretics. The doctor should be informed if you take any medicinal substance. If possible, you should refrain from using them. If medications are taken without the possibility of a break, then you should be aware of possible changes final result

as a result of their influence.

Before the analysis itself, in the evening, you should not eat anything, you can only drink water. You should brush your teeth at night, as the toothpaste may contain substances that distort the data.

Before prescribing GTT, it is necessary to take into account possible contraindications:

The test involves measuring glucose levels three times. The material is venous blood. First fence

carried out on an empty stomach in the morning (at 8-9 o'clock). After taking blood, the woman is given a diagnostic cocktail to drink, a solution of water (about 200 ml) containing from 75 to 100 g of glucose. If in the first two tests it is determined normal value , then, 2 hours after taking the “cocktail” you need to take .

3 units of blood

note

In the case of clearly increased values ​​in the first sample, a sugar load is not required. If the sugar level is increased in 2 servings, then the third measurement is not required.

Some pregnant women find it difficult to drink a sweet solution. They may develop nausea, so in this case, you can use a slice of lemon to ease the taste sensation. Carrying out the test requires relative physical and emotional rest. Except

In addition, pregnant women experience weakness during the study. Therefore, they are recommended to stay in a medical institution during the test.

Normally, a woman preparing to become a mother may have higher sugar levels than usual. This is a physiological rise caused by the needs of a growing child.

The norm is:

1. up to 5.1 mmol/l (at the first intake, before the sugar load);
2. up to 10 mmol/l (second portion of blood, after 30-60 minutes);
3. up to 8.6 mmol/l (2 hours after the start of the test)

After 3 hours, the glucose level normally decreases to 7.8 mmol/l.

If the first blood test shows a sugar value above 7 mmol/l, then the presence of type 2 diabetes can be immediately suspected. No further research is required.

If 2 and 3 servings are outside the norm, there are prerequisites for establishing gestational diabetes. Against this background, a repeat study will be required to accurately confirm the pathology and exclude false result. If it turns out to be positive, then the woman will be recommended to undergo a third study, but after childbirth, to accurately confirm/absence the presence of type 2 diabetes.