Pregnancy is a special condition for the female body. The changed hormonal background contributes to fluctuations in the level of glucose (sugar) in the blood, even in completely healthy expectant mothers. This article will help women understand what a glucose tolerance test is and why it is performed.
What it is?
For the normal functioning of the body of a pregnant woman and her unborn baby, a constant blood glucose level is very important. This substance is involved in all metabolic processes. The function of muscle cells and the brain is directly dependent on blood sugar levels.
Pregnancy is a time when a wide variety of hormones “rage” in the female body. This is a truly unique period, since a large number of completely new hormonal substances appear in the peripheral blood. This condition can lead to the fact that the endocrine system begins to work in a "special mode". It also contributes to a significant change in the level of some hormones and biologically active substances. This situation also applies to blood glucose.
The increased sugar content in the peripheral blood is dangerous to the fetus. If there are signs of hyperglycemia (high glucose) in the blood of the expectant mother, then this can lead to the development of diabetes mellitus or other equally dangerous endocrinological pathologies in her and her baby in the future.
The glucose tolerance test (GTT) is a unique study that allows you to establish accurate peripheral blood glucose levels from the expectant mother. It is prescribed to all pregnant women with certain medical indications to establish the first signs of gestational diabetes mellitus. This pathology manifests itself for the first time only during pregnancy and is associated with a disturbed hormonal background.
Conducting a glucose tolerance test during pregnancy reveals even the "hidden" signs of an increase in blood glucose that the expectant mother has.
When is analysis required?
A glucose tolerance test should be done for all pregnant women. Endocrinologists and obstetricians-gynecologists from different countries say that the incidence of gestational diabetes is growing steadily every year. This explains the importance of such a test for expectant mothers.
It should be noted that it is quite easy to carry out it. The glucose tolerance test is very affordable and does not require any complicated apparatus for its conduct.
Doctors identify several additional clinical situations when such a study is extremely necessary.
Contraindications for conducting
A glucose tolerance test, like any other laboratory study, has not only indications for its conduct, but also certain limitations. Many moms are afraid of this study and try to refuse to take it. Doctors never tire of explaining to them that they should not be afraid of this laboratory test. It will not bring any harm to either the expectant mother or her baby. You cannot get diabetes mellitus after a glucose tolerance test.
There are several clinical situations when this study is not carried out. In this case, the risk of developing possible adverse consequences increases significantly. Many of these clinical situations are temporary. In this case, the test can be postponed somewhat.
It is not worth conducting research when:
- acute course of infectious diseases. Severe inflammation in the body is a significant contraindication for this method. In this case, you can conduct a glucose tolerance test after mom recovers from a viral or bacterial infection;
- gestation at 32 weeks. The last trimester of bearing a baby is not the best time for such a test. The risk of getting false positives during this period is extremely high. In this case, screening of diabetes mellitus and various disorders of glucose metabolism is carried out in the mother and her baby after the delivery;
- exacerbation of chronic or an attack of acute pancreatitis. This pathological condition is accompanied by severe functional disorders caused by inflammation of the pancreas. In the acute period of this disease, the amount of biologically active enzymes in the blood not only increases, but also the content of glucose and insulin changes significantly. It would be better to conduct a glucose tolerance test after such an attack subsides;
- some diseases of the endocrine system. Severe Cushing's disease, clinically active hyperthyroidism, acromegaly are medical contraindications for the study;
- long-term forced use of certain medicines... Taking glucocorticosteroids and estrogens can lead to false positive results. This can distort the correct interpretation of the analysis.
Currently, in any pharmacy near the house, quite a lot of different devices are sold - glucometers. They measure capillary blood sugar levels. Such a device is essential for every family. It will also be required in cases where a close relative is sick with diabetes.
Reviews of some mothers on the Internet indicate that they tried to conduct a glucose tolerance test on their own. It should not be done right away for many reasons! Such home study would be inaccurate and will not give a reliable result after carrying out. It is also worth noting that in some cases it is extremely dangerous to hold it at home. It is necessary to perform a glucose tolerance test only in a medical institution under the supervision of specialists.
The uncontrolled conduct of such a test can even lead to the fact that you have to urgently call the emergency medical team. Some moms make the significant mistake that they can replace glucose intake with chocolate or a regular meal. This is a big mistake. In this case, it is almost impossible to achieve the required exact result.
Methodology
This laboratory study can be carried out in different ways. The standard method is an oral test with 75 g glucose. During the study, a pregnant woman should be in a medical facility for 2-2.5 hours. This provides for the specificity of the technology of this study.
Quite often, a pregnant woman is asked to sit in the corridor if the examination is carried out in an ordinary clinic. Frequent clinics offer visitors a more comfortable environment. During the analysis, the expectant mother can wait in a special room. For a more comfortable pastime, there is usually a TV. It is better to shorten the time between blood sampling for analysis by reading a book.
The glucose tolerance test will be performed in several stages. The first time blood is taken from a vein in the morning. To do this, the expectant mother must come to the clinic strictly on an empty stomach. It is strictly forbidden to eat immediately before performing the study.
Doctors set the required time interval, for how many hours food should not be eaten before the analysis. As a rule, it is from 8 to 14 hours... This is the necessary time when you can get a reliable result in the future. Longer fasting is not required, as this condition can lead to a pronounced decrease in glucose in the peripheral blood.
The basic test procedure is for a pregnant woman to drink a glass of glucose. It tastes sweet, very pleasant. There are currently various glucose metabolites that can be used to perform this test. One of these tools is monohydrate... If glucose metabolites are administered orally, by injection, then the dosages in this case change significantly.
After a pregnant woman has drunk a glass of glucose, then blood is taken to determine glucose from her 4 more times, every 30 minutes. To evaluate the result, all obtained values are used in the future. In some cases, you can conduct research in a different way.
In this case, venous blood is taken for analysis immediately and 2 hours after the first sampling. It is important to note that false positive results can still occur.
In some laboratories, a little lemon juice is added to it to improve the palatability of this diagnostic sweet solution. This does not affect the result obtained, but can significantly reduce nausea during this study. Some mothers, coming to this study at the clinic, take with them a slice of lemon. Citric acid is especially helpful for expectant mothers who have severe gestosis or an increased vomiting reflex.
Currently, capillary blood is not taken from the finger for analysis. A more reliable result helps to obtain venous blood. It shows a more accurate concentration of glucose levels in the body. In capillary blood, mixing with lymph occurs, which leads to a somewhat unreliable result.
Blood collection from a vein is now very safe. Many moms-to-be are tolerating this research quite calmly. As a rule, taking blood from a vein is transferred by them much easier than frequent punctures of a finger. The fine needles used to perform this test do not cause any pain.
For the study, special vacuum tubes are used. They allow you to quickly take very little venous blood for analysis. This feature is due to the difference in pressure between the inside of the tube and the external environment.
The safety of blood sampling with such vacuum syringes is quite high, since only disposable medical instruments are used.
Inside the tubes into which the blood is drawn, there are special chemicals that prevent the oxidation of the blood. These drugs also help maintain a certain glucose concentration over time. Their use allows you to get a fairly reliable result. In some situations, it is possible to simultaneously determine the level of glycated hemoglobin.
To obtain the result, a test tube with venous blood is placed with a special apparatus - analyzer. The modern instruments used for this test are now fully automatic. They allow you to get not only accurate, but also very reliable results. However, in some cases, technical errors are still possible. This usually happens more often when the technique of blood sampling by a laboratory assistant is violated.
Training
Before carrying out this laboratory analysis, recommendations are given to all expectant mothers. Compliance with them is necessary to obtain a more reliable result. It should be remembered that if the obtained values of the glucose tolerance test turn out to be unreliable, then in this case the doctor will prescribe a second examination.
In order to avoid this, you should still carefully carry out the necessary preparation before the test.
A variety of factors can influence the accuracy of your results. Drinking even a small amount of alcoholic beverages can provoke a distortion of the result. To obtain more accurate values, on the eve of the study, you should also exclude the intake of any alcoholic medicinal tinctures. If a pregnant woman abuses cigarettes, then it should be noted that smoking on the eve and immediately before such a diagnostic procedure is strictly prohibited.
Acute infectious diseases or exacerbations of chronic diseases of internal organs, accompanied by an increase in body temperature, lead to the fact that the results of the study are significantly distorted. 2-3 days before carrying out this laboratory test, physical activity should be excluded. Even trivial cleaning of an apartment can lead to the fact that the results can be significantly distorted.
If the study is carried out in a hot season, then the result of such a test may be distorted. Dehydration of the body also quite often provokes a distortion of the results obtained.
In order to avoid this, the expectant mother should observe the usual physiological drinking regime before the glucose tolerance test.
Severe psychoemotional stress a few days before the laboratory test can lead to distorted results. In this case, both false positive and false negative results can be obtained. Doctors recommend that a pregnant woman before taking this test do not be nervous and try to be as calm as possible.
Analysis rate
An elevated glucose tolerance test (OGTT) can occur in a variety of clinical situations. If, during the study, persistent increases in glucose levels were detected, then the test should be further rechecked. Only then can doctors diagnose gestational diabetes. You should also donate blood for research several times, as required by the method of performing this test.
Gestational diabetes mellitus Is an extremely unfavorable disease with a progressive increase in unfavorable symptoms. In this case, false overdiagnosis can lead to the fact that a pregnant woman is prescribed drugs that will lead to undesirable effects. Only an endocrinologist can diagnose gestational diabetes. To do this, he can send the expectant mother to the laboratory for delivery and other auxiliary laboratory tests.
Normal fasting blood glucose values should be less than 5.1 mmol / L. After 60 minutes, the sugar level should not exceed 10 mmol / L. 2 hours after the study, its blood values in a healthy pregnant woman do not exceed 8.5 mmol / l.
Decoding the results
Doctors identify several criteria indicating the presence of signs of gestational diabetes in the body of the expectant mother. In this case, fasting glucose is in the range of 5.1 to 6.9 mmol / L. After 55-60 minutes, its values increase above 10 mmol / L. After a couple of hours, peripheral blood sugar values reach values from 8.5 to 11 mmol / l.
There are also clinical situations where gestational diabetes management is somewhat easier. In this case, the fasting glucose level should be more than 7 mmol / L. After consuming the sugar solution, the blood sugar content exceeds 11 mmol / l. Doctors can regard this condition as a vivid manifestation of diabetes mellitus.
If an increase in the values of the glucose tolerance test occurred only during pregnancy, then this pathological condition is called gestational diabetes mellitus. It is important to note that identified deviations can return to normal after the birth of the child. Such a transient condition should be a reason for mommy to monitor blood sugar periodically regularly throughout her life.
To confirm the diagnosis, a mandatory determination of glycated hemoglobin is required. This indicator shows the dynamics of blood glucose levels over several months. Currently, experts in many countries use this indicator to verify established diagnoses of diabetes mellitus. Normally, the reading of glycated hemoglobin should not exceed 6.5%.
Such combined tests are necessarily carried out for all expectant mothers who are at increased risk of developing diabetes mellitus. During the entire period of pregnancy, these studies can be performed several times. This allows for more accurate results. After childbirth, the level of glycated hemoglobin is also determined and the content of glucose in the peripheral blood is estimated.
If the indicators have returned to normal, then the diagnosis of diabetes mellitus is excluded.
If mommy is at a high risk of hyperglycemia, then she should conduct a study with a sugar load at 24-28 weeks of gestation. Research within this time frame is the best screening for diabetes. In late pregnancy, it is much harder and more dangerous for the fetus to identify abnormalities.
If the test of the future mom shows a significant excess over normal indicators, then she will definitely be assigned a special therapeutic food. It significantly limits "fast" carbohydrates in the daily diet. In this case, it is strictly forbidden for a pregnant woman to eat buns, sweets and chocolate.
An alternative to such dangerous carbohydrates can be quite healthy fruits. However, it should be remembered that they also contain a fairly large amount of fructose - a natural sugar. They should be consumed in dosage.
Sweet carbonated drinks, as well as packaged juices from the daily diet of the expectant mother, who has signs of gestational diabetes, are completely excluded. The best drinks in this case will be plain water, as well as unsweetened compotes and fruit drinks, home-cooked from fruits or berries.
The entire further period of pregnancy of the expectant mother, who has signs of gestational diabetes, proceeds under the mandatory supervision of an endocrinologist. To identify the dynamics of the development of the disease in a pregnant woman, blood is taken several more times to determine the sugar level in it.
As a rule, the appointment of antihyperglycemic drugs is not carried out. Such drugs are usually prescribed for severe and poorly controlled course of this pathological condition.
For information on how to properly make a glucose tolerance test during pregnancy, see the next video.
