Glucose tolerance test (how to take it, results and norm). How to carry out a glucose tolerance test (instructions, explanation) Glucose tolerance test during pregnancy 100 grams of sugar

Paying attention to your health will help the expectant mother safely carry and give birth to a healthy baby.

40 weeks of pregnancy is not only a time of waiting, hope, excitement and joy. During this period, the expectant mother also undergoes numerous examinations, and also takes all kinds of tests. The purpose of such careful monitoring is to monitor the course of pregnancy, as well as timely diagnosis of problems and correction of pathological conditions. Among the studies whose validity is controversial is the glucose tolerance test. How advisable is it to take this test for all expectant mothers without exception?

Glucose and its role in the body of a pregnant woman

The key source of energy for the lion's share of the body's cells is sugar. It is “brought” into the body by foods rich in carbohydrates, and some sugar (in the form of glycogen) is also secreted by the liver. The beneficial component enters the blood, which carries it throughout the body. However, glucose cannot penetrate the cells on its own; insulin comes to its aid.

Normal, insufficient or excessive production of this protein substance determines the glucose content in the blood - within the normal range or with a deviation in the direction of increase or decrease. Increased, as well as insufficient, inclusion of glucose in the blood has a negative effect on both the health, and, consequently, the well-being of the woman, and on the course of pregnancy.

High glucose levels during pregnancy are fraught with the development of fetal pathologies, a sharp increase in the child’s weight, and metabolic disorders in a woman (including the development of gestational diabetes, late toxicosis).
Insufficient presence of sugar in the blood often leads to disturbances in the general condition of the expectant mother - headache, feeling of weakness, fatigue, increased sweating, blurred vision.

One of the tests to diagnose the level of sugar inclusion in the blood of a pregnant woman is a glucose test with an additional load.

Glucose tolerance test during pregnancy - justified need or unnecessary examination

Prescribing this type of examination to an expectant mother causes a negative reaction in many women, and this is quite understandable. The procedure often causes discomfort in the form of nausea and dizziness. In addition, the glucose load test is carried out in the morning, for several hours (about 3). At this time (and also the day before in preparation for the study), you should exclude the consumption of any kind of food, which also often poses a certain difficulty for a “pregnant” body. It is for these reasons that many pregnant women refuse to conduct research.
How justified is the purpose of this type of analysis?

Glucose tolerance during pregnancy. Who is at high risk?

Among the risk factors that require additional examination in the form of a test to identify glucose tolerance are:

Excessive obesity in a pregnant woman (mass index exceeds 30).
During a blood sugar test, which was carried out when the pregnant woman was registered, the inclusion of glucose in the blood was recorded at a level above 5.1 mmol/l.
There is a history of a disorder in the form of gestational diabetes (during previous pregnancies).
Urine analysis showed the presence of glucose in the urine during pregnancy.
The pregnant woman has relatives (close) with established diabetes mellitus.
The expectant mother is carrying a large fetus or has given birth to a large baby in the past.
The pregnant woman’s age has “crossed” the threshold of 35 years.

The presence of at least one of the factors listed above is in favor of conducting a tolerance test. Moreover, the presence of “aggravating circumstances” is often an indication for prescribing a glucose tolerance test twice - when a woman applies for registration (classic analysis to determine sugar content) and in the second trimester of pregnancy.

When is it indicated to donate blood for glucose during pregnancy?

The detection of the symptoms listed below should force the expectant mother to undergo an unscheduled examination with a carbohydrate load.

The appearance of a metallic taste in the mouth.
The need to urinate frequently.
Increased fatigue, constant fatigue.
Elevated blood pressure readings.

The final decision on whether to conduct a glucose test is made, of course, by the woman, but she should listen to the recommendations of the doctor who is monitoring her pregnancy. Some conditions of a pregnant woman require additional attention, so you should not neglect the doctor’s advice. Gestational diabetes, which is not detected in a timely manner, threatens serious complications not only for the woman, but also for the child she is carrying. A proper diet, combined with individual recommendations, will negate the negative impact of pathology.

Glucose test during pregnancy: preparation for the test

Proper preparation for analysis is one of the most important components of a reliable research result.

A few days (three days is enough) before the test, the expectant mother should completely eliminate all fatty and spicy foods, coffee, cakes, and smoked foods from her diet. By the way, a woman “in position” should not abuse such delicacies the rest of the time. It is best to stick to a neutral diet.
Taking medications can also affect the test results, resulting in a false result. This statement applies especially strictly to: multivitamins, medications containing iron, drugs to lower blood pressure, diuretics, corticosteroid hormones. When taking any medications, a pregnant woman must notify her doctor about the therapy.
It is very important to maintain the usual mode of physical activity, not to “sleep”, but also not to be too zealous.
The last meal on the eve of the test should occur at least 8 hours before (and preferably 10-14 hours before). During this period you can only drink water.
It is also strictly prohibited to smoke and drink alcohol (which is already contraindicated for pregnant women).
You should brush your teeth at night. Before taking the test, it is better to skip this hygienic procedure, because Some components of toothpaste can distort test results.
Try to avoid increased anxiety and stressful situations.

How to take a glucose test during pregnancy

The optimal period for taking a stress test for sugar is considered to be the period from the 24th to the 28th week of gestation. The Carbohydrate Load Test procedure includes the following steps:

A pregnant woman comes to a medical facility and donates the first portion of venous blood on an empty stomach. Depending on the data obtained at the first stage, a decision is made on further research. So, if the glucose level is already exceeded, the exercise test is not performed. The woman is referred for further examination and clarification of the diagnosis with suspected gestational diabetes. If the sugar level is normal, a glucose tolerance test is prescribed.
The second stage is glucose loading during pregnancy by oral administration of a glucose solution. A woman should drink 250-300 ml of warm water, in which 100 g or 75 g of dry glucose is diluted. The amount of monosaccharide is determined by the doctor ordering the study. 60 minutes after absorption of the glucose solution, the blood sugar concentration is measured. An alternative method of administering the solution may be intravenous administration of the composition, although direct injection of glucose into the blood is not often practiced.
The third stage involves recording blood glucose numbers 2 hours after the carbohydrate load test.

The data obtained is checked against the standards and a conclusion is drawn about the state of health of the pregnant woman.

Glucose levels during pregnancy: interpretation of test results

Interpretation of test results is based on data obtained as a result of three measurements of the level of glucose in the blood. When assessing the result obtained, you can rely on the following criteria:

1. Indicators of blood sugar concentration when collecting biological material on an empty stomach and without load are:

below 5.1 - 5.5 mmol/l (taking into account laboratory reference values) is normal;
in the range of 5.6 - 6.0 mmol/l - deviations in glucose tolerance;
6.1 mmol/l or more - suspicion of diabetes (in a number of laboratories this indicator is in the range of 7 mmol/l and above).

2. Measuring glucose incorporation 60 minutes after an additional carbohydrate load:

less than 10 mmol/l is normal;
in the range of 10.1 - 11.1 mmol/l - deviations in glucose tolerance;
11.1 mmol/l or more - suspected diabetes.

3. Fixing the sugar content 120 minutes after a glucose load:

less than 8.5 mmol/l indicates normal;
in the range of 8.6 - 11.1 mmol/l - deviations in glucose tolerance;
11.1 mmol/l and above is a clear deviation, possibly gestational diabetes.

Table for assessing glucose levels during pregnancy: norm and deviations

Depending on the type of research method, the normal limits in different laboratories may vary slightly. In view of this, it is very important to evaluate the result solely in accordance with the criteria of a given research center.

Analysis result: increased glucose during pregnancy

Even if the test results reveal a discrepancy with the normal criteria, you should not immediately panic. This violation may be due to:

Increased hormonal activity of the adrenal glands.
Excessive activity of the thyroid gland.
Pathologies of the pancreas.
Long-term use of glucocorticoids.

Additional examinations will help clarify the cause of the violations.

Test result: low glucose during pregnancy

A downward deviation is less common than an elevated glucose level. This violation may be associated with:

Severe form of early toxicosis.
Unbalanced diet of the expectant mother.
Lack of body weight in a pregnant woman.

A low sugar content, in addition to disturbing the general condition, can also lead to increased production of ketone bodies, which have a toxic effect on the female body. Drug therapy for low sugar levels is not prescribed. A woman is advised to eat a balanced diet with sufficient calories. In some cases, glucose drips may be prescribed.

Glucose test during pregnancy: contraindications for testing

A referral for a glucose load is issued by a doctor who is observing the expectant mother. A number of conditions are a contraindication to this type of research. These include:

Gestation period is more than 28 weeks. Conducting a tolerance test in the third trimester of expecting a baby can be dangerous for him. That is why the study can be scheduled in the period from the 28th to the 32nd week of gestation of a toddler strictly for medical reasons. After the 32nd week, a glucose load is never prescribed.
Glucose intolerance.
Presence of infection (including mild colds), foci of inflammation.
Bed rest for a pregnant woman. To adequately assess the test results, moderate physical activity of the expectant mother is necessary.
Exacerbation of pancreatitis - inflammation of the pancreas.
Ulcerative lesions of the gastrointestinal tract.
Therapy with drugs aimed at increasing glycemic levels. Conducting research in this case will be pointless.
If the blood sugar level (when taken on an empty stomach) exceeds 7.0 mmol/l. The exact norm depends on the criteria of a particular laboratory (it could be 5.1 mmol/l).
Severe toxicosis. The analysis procedure is unpleasant and can further aggravate the manifestations of toxicosis.

Additional sugar loading by performing a glucose test during pregnancy is a mandatory test. However, the decision on the need to conduct research in each individual case should be made by the doctor and the woman together.

During the entire 9 months when the expectant mother is carrying a child, she has to conduct many different examinations, to which new ones are added every year. Such diagnostics are used to identify abnormalities in the development of the baby or during pregnancy. One of these necessary tests is a glucose tolerance test during pregnancy. Let's figure out the purpose of it, how to take it, is it necessary to do it?

Basic information

Glucose tolerance test - makes it possible to identify the presence of disturbances in carbohydrate metabolism. In other words, the body’s response to the content (level) of glucose in the blood is diagnosed. The test can detect the presence of a disease such as diabetes and even a possible predisposition to its occurrence. Thanks to the results of the study, it is possible to start treatment in a timely manner or prevent the development of the disease.

You need to understand that pregnancy itself can lead to disruptions in the functioning of the body. Since gestational diabetes is asymptomatic, it is difficult to determine the presence of a latent form of the disease. Therefore, carrying out this testing will allow us to identify the disease and begin treatment, which will protect the expectant mother and baby from possible pathologies.

If a woman is diagnosed with gestational diabetes, she should be under close supervision of an endocrinologist and gynecologist.

This type of diabetes is not considered a serious disease, as it disappears immediately after pregnancy. However, if therapy is not carried out, it may pose a certain danger to the embryo and the expectant mother.

When to test?

The most suitable period for performing GTT is 24–28 weeks. A glucose test during pregnancy may be prescribed earlier if:

The woman has already encountered this problem or has already been diagnosed with gestational diabetes.
The embryo is large (in a real pregnancy) or the woman has already given birth to a large baby (weight 4.5–5 kg).
The woman is overweight (mass index above 30).
Relatives have diabetes.
There is sugar in the urine.
When a pregnant woman is registered, the glucose level in her blood exceeds the norm.

If one of the above points is present, a glucose tolerance test during pregnancy can be performed at 16-18 weeks. It makes no sense to do it earlier, because resistance to insulin increases only from the 4th month of pregnancy. Then (at 24–28 weeks) GGT should be repeated.

Contraindications

Testing is possible in the 3rd trimester, but not after 32 weeks, since increased glucose load can be dangerous for the mother and embryo.

The test is not prescribed for use in the following cases:

Liver dysfunction in a pregnant woman.
Diseases of the endocrine system.
Dumping syndrome.
Symptoms of an “acute” abdomen.
The presence of infection or inflammation in the woman at the time of testing.
Late stage (after 32 weeks) of pregnancy.
Crohn's disease.

When a pregnant woman suffers from severe early toxicosis, the test is not recommended, because the glucose composition is too sweet and will lead to a gag reflex.

Methodology

A glucose tolerance test during pregnancy is performed in the morning, on an empty stomach, using a venous blood test. It is not recommended to eat 8-10 hours before the GTT; in the morning (before the analysis) you should not drink water, tea or coffee.

The analysis consists of several stages:

If the test shows a glucose reading that is above the upper normal level (5.1 mmol/L), no further testing is performed. A diagnosis of gestational diabetes is made.
If the values are within normal limits, an oral test is performed. Dry glucose (approximately 75 g) is dissolved in a glass of water. A woman should drink this glucose composition very slowly (not in one gulp), the recommended time is 5-7 minutes.
After 60 and 120 minutes, additional blood tests are performed. If necessary, a 3rd test is also done.

During testing, the woman should be at rest; she is not allowed to eat or drink carbonated water.

It is desirable that the woman feels well, since even the presence of simple rhinitis can lead to a distortion of the result. If a pregnant person takes medications (even vitamin formulations), then when prescribing a “sugar load”, the doctor should be informed about this.

Establishing diagnosis

Thanks to such a GTT examination, the doctor will be able to determine how changes in sugar levels occur in the body. Normally, the glucose concentration when taking a cocktail increases sharply, but gradually decreases, and after 120 minutes it returns to normal limits.

A woman is diagnosed with gestational diabetes if two of the following abnormalities are detected:

with 1 repeat analysis performed after 60 minutes, the glucose level exceeds 10.0 mmol/l;
2nd repeat – more than 8.6 mmol/l.
3 analysis showed a result higher than 7.8 mmol/l.

A study of glucose tolerance will have a distorted result if a woman is very excited, after an emotional breakdown, physical exertion, when the blood contains an insufficient amount of potassium.

There is no need to think that the test can harm the mother or baby. If you do not carry it out if there are contraindications, there will be no negative effects on the body. Even if a woman had diabetes, but she did not know about it before the test, a glucose cocktail will not harm.

If the GTT results are threshold or the doctor suspects a possible development of the disease, a blood glucose test is ordered again, most often 10-14 days after the first test. If the diagnosis is confirmed, the woman should be tested again for glucose tolerance.

Many expectant mothers who developed diabetes while carrying a child are very worried that this will complicate the course of pregnancy. Don't worry, the doctor will prescribe a special diet and exercise. You will be constantly under medical supervision, since examinations will be more frequent and their duration will also increase.

Most women with this type of diabetes give birth to healthy children, and the sugar test will be normal after a while.

The body of a woman carrying a child sometimes undergoes such dramatic changes that can negatively affect her health and well-being. In addition to toxicosis, edema, anemia and other troubles, carbohydrate metabolism disorders, classified as gestational diabetes (GDM), may also appear. A glucose tolerance test during pregnancy helps to identify or exclude such conditions.

Indications and contraindications

According to the Ministry of Health protocols, all expectant mothers should undergo this study between 24 and 28 weeks. The analysis of the sugar curve during pregnancy is most important for women who are in the risk category. For example, if there are documented cases of diabetes in the family or the patient herself already had problems with carbohydrate metabolism. Expectant mothers whose urine tests have detected glucose should be examined. Overweight women are also at risk.

A glucose tolerance test (GTT) in pregnant women with risk factors is carried out immediately after registration, then again from 24 to 28 weeks.

A referral for examination is given by the attending physician, indicating the dosage of the monosaccharide. There are a number of contraindications to GTT:

Glucose loading is contraindicated in women whose fasting blood sugar level exceeds 7.0 mmol/L (5.1 mmol/L in some laboratories).
The test is not performed on patients under 14 years of age.
In the third trimester, after the gestation period of 28 weeks, the carbohydrate load poses a danger to the fetus, therefore it is carried out strictly according to the doctor’s indications. After 32 weeks it is never prescribed.
The test is not performed for inflammatory processes, infections, exacerbation of pancreatitis, dumping syndrome.
It makes no sense to conduct a study for impaired glucose tolerance against the background of pharmacotherapy with drugs that increase glycemic levels.
For pregnant women with severe toxicosis, the test is dangerous due to a number of consequences. Loading with carbohydrates doesn't feel good and can only make nausea and other symptoms worse.

Preparing for testing

In order for the results of a glucose tolerance test during pregnancy to be reliable, you need to properly prepare for the test. It is important not to change your usual diet for three days before GTT, eat enough carbohydrate foods. The usual regime of physical activity during this period is also required. The night before the glucose tolerance test, you are only allowed to drink water and not eat food for at least 8 hours. It is important to completely abstain from alcohol 11–15 hours before the test. Smoking is also prohibited during this time. The last meal should include at least 30 g of carbohydrates.

If you follow a number of these mandatory rules, the GTT test will go smoothly and the results will be reliable. It is better to contact your doctor so that he can tell you in detail how to take the two-hour test correctly. It is also worth consulting with him about the likely risks, harm to the unborn child, the feasibility of the study and the possibility of refusing it.

Procedure for conducting GTT

How to take a glucose tolerance test during pregnancy? First, you should properly prepare for the study, following all the doctor’s recommendations. Testing begins with taking blood from a vein on an empty stomach for analysis and recording the sugar level, then carrying out a carbohydrate load. Some laboratories will first take a finger prick sample and measure your glucose levels using test strips. If the obtained value exceeds 7.5 mmol/l, carbohydrate loading is not carried out.

The simplest option is an oral glucose tolerance test (OGTT), when the patient drinks a solution of glucose with water within 5 minutes. For certain indications, when such a test cannot be performed, for example, due to severe toxicosis, glucose is administered intravenously. The dosage of the monosaccharide in different laboratories is different, it can be 75g or 100g. It is up to the doctor to determine this.

After a carbohydrate load, sugar levels are measured in two stages: after 1 hour, then after 2 hours. Smoking and increased physical activity are prohibited until testing is completed. If your blood sugar readings are outside the normal range during pregnancy, this may be a sign of gestational diabetes. However, a definitive diagnosis can only be made after consulting an endocrinologist. To clarify the severity of carbohydrate metabolism disorders, a blood test for glycated hemoglobin is prescribed.

Decoding and interpretation of results

Diagnostic criteria for glycemic disorders are established by WHO. Indicators of normal glucose in blood plasma from a vein (load of 75 g):

in the morning on an empty stomach – less than 5.1 mmol/l,
after 1 hour – less than 10 mmol/l,
after 2 hours – less than 8.5 mmol/l.

Impaired glucose tolerance (IGT) is determined by the following indicators:

in the morning on an empty stomach – from 5.1 to 7 mmol/l,
or an hour after a carbohydrate load – 10 mmol/l or more,
or two hours later - from 8.5 to 11.1 mmol/l.

Indicators of carbohydrate levels in the blood plasma above normal indicate gestational diabetes. However, an abnormal sugar curve during pregnancy is sometimes a false positive result associated with recent surgery, acute infection, taking certain medications, or severe stress. To avoid misdiagnosis of impaired glucose tolerance, you need to follow the rules of preparation for testing and tell your doctor about factors that can distort the results.

A clear indicator of diabetes mellitus is exceeding the limit of 7 mmol/l in a sample taken on an empty stomach or the limit of 11.1 mmol/l in any other sample.

Is it worth agreeing to testing at all?

Taking a glucose tolerance test during pregnancy is a concern for many women. Expectant mothers are afraid that this will have a negative impact on the fetus. The procedure itself often brings discomfort in the form of nausea, dizziness, and other symptoms. Not to mention that you need to allocate at least 3 hours from the very morning for a glucose load test, during which you cannot eat. This is why pregnant women often want to refuse the study. However, you should realize that it is best to discuss this decision with your doctor. He will evaluate the feasibility of the study based on various factors, including how far along the patient is, how the pregnancy is progressing, etc.

Unlike us, in Europe and the USA, women with a low risk of developing glycemic disorders are not screened for glucose. Therefore, refusing testing seems justified for pregnant women who fall into this category. To qualify as low risk, all of the following statements must be true:

You have never had a situation where a test showed that your blood glucose level was higher than normal.
Your ethnic group has a low risk of diabetes.
You do not have a first-degree relative (parent, sibling, or child) with type 2 diabetes.
You are under 25 years old and of normal weight.
You did not have poor results on GTT during a previous pregnancy.

Before you decide not to get tested, consider the consequences of undiagnosed gestational diabetes. It carries with it a high incidence of complications for the baby and the mother herself, and increases the risk of developing type 2 diabetes in the mother over time.

From the very beginning of pregnancy, significant changes in metabolic processes, including carbohydrates, occur in a woman’s body. In order to identify violations of the latter, determination of blood sugar levels and an oral glucose tolerance test during pregnancy are used. Compared to men, diabetes mellitus is much more common among women, and there is a clear association with the gestational period and childbirth - GDM (gestational diabetes mellitus).

Methods for identifying impaired carbohydrate metabolism

The prevalence of diabetes among pregnant women on average in Russia is 4.5% of their total number. In 2012, the Russian National Consensus defined GDM and recommended new criteria for its diagnosis, treatment and postpartum care for practical use.

Diabetes mellitus in pregnant women is a disease characterized by high blood sugar levels, which is detected for the first time, but does not meet the criteria adopted for a newly diagnosed (manifest) disease. These criteria are:

fasting sugar content is more than 7.0 mmol/l ( further in the text the same names of units of measurement) or equal to this value;
glycemia, confirmed in a repeated analysis, which at any time during the day and regardless of diet is equal to or greater than 11.1.

In particular, if a woman’s fasting venous plasma sugar level is less than 5.1, and during an oral glucose tolerance test 1 hour after exercise it is less than 10.0, after 2 hours it is less than 8.5, but more than 7.5 - these are normal options for a pregnant woman. At the same time, for non-pregnant women, these results indicate a violation of carbohydrate metabolism.

At what stage is a glucose tolerance test performed during pregnancy?

Identification of carbohydrate metabolism disorders is carried out in stages:

Stage I of the examination is mandatory. It is prescribed at the first visit to a doctor of any profile by a woman for up to 24 weeks.
At stage II, an oral glucose tolerance test is carried out with 75 grams of glucose at 24-28 weeks of pregnancy (optimally 24-26 weeks). In certain cases (see below), such a study is possible up to 32 weeks; if there is a high risk - from 16 weeks; if sugar is detected in urine tests - from 12 weeks.

Stage I consists of conducting a laboratory test of glucose in blood plasma on an empty stomach after an 8-hour (no less) fast. It is also possible to test blood regardless of diet. If the norms are exceeded, but the blood glucose level is less than 11.1, then this is an indication for repeating the test on an empty stomach.

If the test results meet the criteria for newly diagnosed (manifest) diabetes, the woman is immediately referred to an endocrinologist for further observation and appropriate treatment. If the fasting glucose level is higher than 5.1 but less than 7.0 mmol/l, GDM is diagnosed.

How to perform a glucose tolerance test during pregnancy

Indications

A glucose tolerance test is performed on all women in the following cases:

There are no deviations from the norm in the results of phase I examination in the early stages of pregnancy.
The presence of at least one of the signs of a high risk of GDM, ultrasound signs of carbohydrate metabolism disorders in the fetus, or certain ultrasound signs of fetal size. In this case, the test can be carried out up to and including the 32nd week.

Signs of high risk include:

high degree of obesity: body mass index is 30 kg/m2 and above;
presence of diabetes mellitus in immediate (first generation) relatives;
history of gestational diabetes mellitus or any carbohydrate metabolic disorders; in this case, testing is carried out at the first visit to the doctors (from 16 weeks).

Is a glucose tolerance test dangerous during pregnancy?

This study does not pose any risk to the woman or fetus up to 32 weeks. Carrying it out after the specified period can be dangerous for the fetus.

Testing is not carried out in the following cases:

early toxicosis of pregnancy;
compliance with bed rest;
presence of diseases of the operated stomach;
the presence of chronic cholecystopancreatitis in the acute stage;
the presence of an acute infectious or acute inflammatory disease.

Preparation

The conditions for conducting a glucose tolerance test include:

Normal meals for the previous 3 (at least) days with a daily carbohydrate content of at least 150 g in the diet.
Mandatory carbohydrate content of 30-50 g in the last meal.
Fasting (but not restricting water intake) for 8-14 hours the night before testing.
Exclusion (if possible) from taking medications containing sugar (pharmaceutical preparations of vitamins and iron, antitussives, etc.), as well as beta-blocking, beta-adrenomimetic and glucocorticosteroid drugs; They should be taken after blood sampling or inform the doctor about the need to take them before testing (for adequate interpretation of test results).
Doctor's warning about conducting a test while taking progesterone.
Stop smoking and keep the patient in a sitting position until the end of testing.

Stages of implementation

They consist of:

Taking the first blood sample from a vein and analyzing it. If the results indicate the presence of newly diagnosed or gestational diabetes mellitus, the study is stopped.
Carrying out a sugar load with normal results of the first stage. It consists of the patient taking 75 g of glucose powder dissolved in 0.25 liters of warm (37-40 ° C) water for 5 minutes.
Subsequent collection and analysis of further samples after 60 minutes, and then after 120 minutes. If the result of the second analysis indicates the presence of GDM, then the 3rd blood draw is canceled.

Interpretation of glucose tolerance test results during pregnancy

So, if the fasting blood glucose concentration is less than 5.1, this is normal, above 7.0 is manifest diabetes; if it exceeds 5.1, but at the same time is below 7.0, or 60 minutes after a glucose load - 10.0, or after 120 minutes - 8.5 - this is GDM.

Tab. 1 Threshold values of venous plasma glucose for the diagnosis of GDM

Tab. 2 Threshold values of venous plasma glucose for the diagnosis of overt diabetes during pregnancy

The correct approach to identifying and treating diabetes (if necessary) significantly reduces the risks of complications during pregnancy and childbirth itself and the degree of threat of developing diabetes in the distant future in women predisposed to it.

Doctors monitor the health of expectant mothers with particular attention, because any malfunction in the functioning of their body threatens the health of not only the woman, but also the fetus. Therefore, doctors and expectant mothers must understand why and how to correctly take a glucose tolerance test during pregnancy. This is one of the mandatory studies for women who are already 25 years old.

Goals

Most modern women are at risk; they are likely to develop diabetes. Expectant mothers who are overweight and have a genetic predisposition are most susceptible to this disease.

A glucose tolerance test allows you to find out how glucose is absorbed in the body. It will show even minor violations. With its help, you can diagnose latent diabetes mellitus or determine whether the process of carbohydrate absorption is impaired.

Is a glucose tolerance test required or not during pregnancy? If the doctor recommends undergoing this examination, then it is not advisable to refuse it. After all, sometimes diabetes can be asymptomatic.

Uncompensated diabetes is the cause of fetal fetopathy. For some, an increase in blood glucose can cause irreversible changes and the appearance of pathologies incompatible with life.

Purpose of the study

Depending on the pregnancy management tactics adopted in a particular clinic, a glucose tolerance test is prescribed to all women in a row or only to those who are at risk.

The study is done at the first visit to the gynecologist. This allows you to determine whether you had diabetes before pregnancy. If there are problems with glucose metabolism, pregnancy is managed in parallel by a gynecologist and an endocrinologist. Such patients donate blood regularly: to monitor their condition, it is better for them to purchase a home glucometer.

If there were no problems, then a special examination is prescribed to identify it. This is one of the serious complications of pregnancy that requires monitoring and treatment. Tests are taken between 24 and 28 weeks.

If sugar was detected in the urine, then GTT is taken from the 12th week; if the expectant mother has a high probability of developing diabetes, then the examination can be scheduled as early as 16 weeks.

Carrying out diagnostics

Doctors usually explain why they prescribe blood tests for glucose. This diagnosis is necessary to determine the mother's health status.

The glucose tolerance test assumes that a woman will have to donate blood 2-3 times.

Collecting material for analysis on an empty stomach with a previous 8-14 hour fast.
Drinking a glucose solution (you should drink 75 grams of glucose dissolved in 300 ml of clean water).
Carrying out a control sampling: in some laboratories, 1 sampling is done, in others - 2, after 1-2 hours.

To obtain an accurate result of the study, you should properly prepare for a glucose tolerance test during pregnancy:

the fasting period should be 8-14 hours, the first analysis is carried out on an empty stomach (you can drink clean water);
on the eve of the study, you should eat your usual food without reducing the amount of carbohydrates (in the last meal there should be about 50-60 g);
exclusion on the eve of the load study from taking medications containing sugar (cough syrups, vitamins), corticosteroids, beta blockers;
absence of severe stress in the days preceding the study;
quitting smoking in the morning before blood sampling (if the woman was unable to give up this harmful habit earlier).

There are 2 methods of administering glucose: oral and intravenous. In the first case, the patient simply drinks a sweet solution, in the second, she is given a glucose drip. The oral method is much simpler, so it is used more often. But the liquid must pass through the stomach and into the bloodstream. This takes time. When administered into a vein, the time it takes for glucose to enter the bloodstream is reduced significantly.

Defining Results

Expectant mothers should know the normal results of a blood test for glucose tolerance in pregnant women. When carrying a child, the sugar level rises slightly - this is a physiological need of the body to provide nutrition to the fetus.

But you should remember the established standards for examination from a blood vein:

on an empty stomach, sugar does not exceed a concentration of 6.1;
after 60 minutes the readings are up to 10;
after 120 minutes – values less than 8.5;
after 180 minutes – up to 7.8.

When studying capillary blood from a finger, different standards are established. Indicators should not be higher than 5.5.

An OGTT analysis with 75 grams of glucose indicates problems if the following is found in venous blood plasma:

fasting readings between 6.1 and 7.0;
120 minutes after taking the liquid - from 7.8 to 11.1.

With diabetes, including gestational diabetes, the rates will be even higher.

Contraindications for testing

But this test is not always carried out. There are certain contraindications:

toxicosis of pregnant women (there is a high probability that due to frequent vomiting, the pregnant woman will not be able to drink the sweet solution; the incoming glucose will not have time to be absorbed);
stomach diseases after operations;
exacerbation of cholecystopancreatitis;
the need for strict adherence to bed rest;
infectious or inflammatory diseases (they affect the results of the sugar test);
Crohn's disease;
dumping syndrome;
late stages of pregnancy.

For these lesions, OGTT is not performed. Even hidden diabetes can be detected using other methods.

Indications for mandatory testing

Women who are at risk must take a glucose test. These include those pregnant women who:

overweight (body mass index close to 30 or even higher);
sugar detected in urine;
negative heredity (close relatives have diabetes);
had diabetes in previous pregnancies;
previous children were born weighing more than 4 kg;
was discovered in the analyzes.

If the specified aggravating circumstances are present, then the analysis is taken earlier. A woman is sent for an appropriate examination already at 16 weeks. If there are no problems, the diagnosis is repeated at 24-28 weeks.

Confirmation of diagnosis and treatment tactics

A one-time glucose tolerance test is not a basis for registering the expectant mother with an endocrinologist. The examination must be repeated and only after that the treatment tactics are determined.

One of the best methods to get rid of the problem with glucose absorption is to follow a diet. Reducing the number of sugars entering the body and replacing simple carbohydrates with complex ones allows you to improve your condition in a short time. Moderate physical activity has a good effect on performance.

When should I get tested again? It is recommended to study blood regularly to prevent a sharp deterioration in the condition and the development of fetopathy in the fetus.

If glucose tolerance has been impaired, then special attention is paid to preparing for childbirth. For gestational diabetes, delivery is planned at 37-38 weeks. In other cases, the condition of the pregnant woman and the fetus is carefully monitored; if there are no deviations, the birth will take place according to the standard scenario.

All expectant mothers should know what impaired glucose tolerance and gestational diabetes mellitus are. These are conditions in which pregnant women receive special attention. They should be regularly examined and monitored sugar concentrations to prevent complications and worsening of the condition.