Deciphering the results of the hCG analysis. Free beta-hCG: features of the hormone, norm and deviation Material for research

Watch a helpful video on this topic

Norms

Statistical indicators of the norm are the basis for ascertaining the presence of deviations in pregnancy or its normal course. For each stage of pregnancy, certain values ​​\u200b\u200bare normal.

In the first trimester, when the membranes of the fetal egg begin to actively produce the hormone, such values ​​\u200b\u200bare the norm.

Many women, in anticipation of the desired pregnancy, are tested for beta-hCG, which makes it possible to determine its onset. However, not everyone knows what this indicator is and what else it can show. Why take an analysis for beta-hCG, how and when is the biomaterial taken?

Data-lazy-type="image" data-src="https://dazachatie.ru/wp-content/uploads/2018/02/3559_vysokiy-khgch-na-pervom-skrin_novyj-razmer.jpg" alt="( !LANG: the doctor takes the analysis" width="660" height="409" srcset="" data-srcset="https://dazachatie.ru/wp-content/uploads/2018/02/3559_vysokiy-khgch-na-pervom-skrin_novyj-razmer..jpg 300w" sizes="(max-width: 660px) 100vw, 660px">!}

HCG is human chorionic gonadotropin. Total hCG consists of a pair of subunits - alpha and beta. Of these two components, b-hCG is not only distinguished by its uniqueness, but also has some properties of its own. In addition, it is free beta-hCG that is present in the basis of the material from which express tests are made to determine the onset of pregnancy.

This subunit contains 145 amino acids, giving it unique properties. With the participation of gonadotropin, a huge number of processes in the body of a woman are carried out.

Both subunits of gonadotropin begin to be produced after direct conception and implantation of the fetal egg to the uterine wall.

An analysis for beta-hCG is prescribed for the purpose of:

• early diagnosis of pregnancy;
• tracking the dynamics of fetal development;
• determination of signs of abnormal development of the fetus;
• exclusion of the development of ectopic pregnancy;
• assessment of the need for re-cleaning after artificial termination of pregnancy;
• determination of risk factors during gestation;
• diagnosis of tumors and amenorrhea;
• confirmation or refutation of the diagnosis of testicular tumors - in the case of an analysis for men.

What is the difference between hCG and beta hCG?

What is the difference between total human gonadotropin and b-hCG? Total hCG is a hormonal subunit, according to which it is possible to diagnose not only the onset of pregnancy, but also other processes in the human body. Whereas the beta subunit appears in the analysis only during conception and implantation of the embryo to the uterine wall, since this hormone is produced exclusively by the cells of the fetal egg.

300w (max-width: 660px) 100vw, 660px">

When pregnancy does not develop in the patient's body, then the following pathological conditions can be determined by the level of alpha-hCG:

• tumor neoplasms that affect the concentration of hormones in the body;
• deviations in the work of the endocrine system.

How and when to take beta hCG?

To determine the level of this hormone, it is necessary to donate blood. When is the hgh test taken? Starting from 3-5 days of delay menstrual cycle or on the 12th day after the expected date of conception, a woman can donate biomaterial for the presence of this hormone in the body. However, at such a short gestational age, the accuracy of the test will be low, so a follow-up check will be required to confirm the assumptions in any case.

To track the dynamics of the hormone, it is necessary to donate blood three times with a difference of 2 days, if possible at the same time.

In obstetric practice, the doctor prescribes an analysis for beta-hCG at a gestational age of 10-12 weeks, since it is during this period that the concentration of the hormone is highest. If the pregnancy is planned, then doctors recommend repeating the procedure at 14-18 weeks.

How is the analysis given? Blood sampling to determine the concentration of the hormone is carried out in the morning on an empty stomach. In the case of passing the analysis in the afternoon, it is forbidden to eat for 4-6 hours before the procedure. Also among the recommendations of doctors is the restriction of active physical activity the day before blood donation. And when taking any hormonal drugs, it is necessary to notify your consulting doctor about this.

It is also worth knowing that this hormone can be determined from amniotic fluid and urine, however, in order to diagnose pregnancy and its development, beta-hCG analysis is taken from a vein.

Data-lazy-type="image" data-src="https://dazachatie.ru/wp-content/uploads/2018/02/HGCH-pri-beremennosti.jpg" alt="(!LANG:pregnant woman" width="660" height="440" srcset="" data-srcset="https://dazachatie.ru/wp-content/uploads/2018/02/HGCH-pri-beremennosti..jpg 300w" sizes="(max-width: 660px) 100vw, 660px">!}

What are the norms for beta hCG?

Deciphering the results of the analysis is carried out by a specialist. He also fixes any deviations from the norm, and also makes a decision regarding therapy in case of discrepancy between the norms.

It should be said right away that the individual characteristics of the body greatly affect the results of the examination. In the normal state, the quantitative proportion of human gonadotropin in the body of both men and women does not exceed 10 IU / l. After the fertilization of the egg by the sperm and its implantation, the level of the hormone begins to rise rapidly and in some situations can reach 500 IU / l. The normal level of hgh indicates that no pathological processes occur in the woman's body and pregnancy develops accordingly.

The indicator of beta-hCG, or rather its norm, depends on the period of gestation of the child. For convenience, all data has been summarized in a table.

If the indicator of the hormone is within the specified limits, then there is no reason for excitement. In case of discrepancy between the data obtained as a result of the study of the biomaterial and the indicators indicated in the table, a re-analysis may be assigned, on the basis of which the doctor will already make a decision.

Outcome

At the end of the publication, let's summarize:

1. HCG is a human gonadotropin composed of alpha and beta subunits.
2. Beta-hCG is a hormonal subunit that indicates the presence of pregnancy in the human body. An analysis for the determination of this hormone is a very important study during the period of bearing a child.
3. There are rules that correspond to a certain period of pregnancy. If the analysis indicators go beyond the limits of the norms, then only the doctor will be able to decide what to do in a given situation.

The individual characteristics of the body can affect the results of the test, not to mention the situations when a woman undergoes hormone therapy, which will clearly affect the performance of the study.

- one of the main hormones that regulate the functions of the sex glands. It performs a number of important tasks in the body of a pregnant woman, helping to maintain the right concentration of other hormones and survive the stress that is gestation.

Given the important role of chorionic gonadotropin, it is not surprising that the analysis of its concentration in the blood is one of the main ones in monitoring pregnancy. The units of measurement for hCG in the test results of several different laboratories may differ, therefore, in order to correctly interpret the results, it is important to know the relationship between them.

Why is hCG so important?

To understand why the content of human chorionic gonadotropin is one of the main markers of a healthy pregnancy (especially in the first trimester), it is necessary to understand its properties and effects on the body.

Along with other gonadotropic hormones (luteinizing and follicle-stimulating), as well as thyrotropin (TSH), hCG consists of an α- and β-subunit. The structure of the hCG β-subunit distinguishes it from the listed hormones (the α-subunit is a homologous similar structural component in FSH and TSH). During pregnancy, it is a determining factor that allows you to set the concentration of this particular hormone due to a specific reaction to the subunit.

In its properties, hCG resembles both other gonadotropic hormones at once. However, despite the ability to bind to both types of receptors, the luteinizing properties significantly prevail over the stimulation of the follicle. In this capacity, hCG is significantly superior to the usual pituitary luteinizing hormone: it is thanks to its high activity that the corpus luteum, which normally exists for the last two weeks of the menstrual cycle, is preserved until the placenta develops sufficiently to produce estrogen and progesterone.

Under the influence of chorionic gonadotropin, the corpus luteum produces a lot, which is required for the normal course of pregnancy. HCG also stimulates the production of estrogens, without which the activation of progesterone, weak androgens and glucocorticoids is impossible, which reduce the immune response to a half-foreign body and avoid miscarriage.

The role of hCG in the body of a pregnant woman explains the dynamics of hormone production: up to 10-12 weeks, its amount is steadily increasing, because. For the normal bearing of the fetus, more and more progesterone is required. After the placenta matures and the secretion of all the hormones necessary for pregnancy by its tissues begins, the need for the existence of the corpus luteum and its intensive stimulation disappears, so the concentration of hCG decreases.

Considering all of the above, an excess or deficiency of chorionic gonadotropin in pregnant women indicates pathologies or diagnostic errors (more likely in the early stages of gestation).

The concentration of chorionic gonadotropin during pregnancy

Human chorionic gonadotropin is considered a placental hormone, despite the fact that in the absence of pregnancy, a small amount of it (not higher than 5 mIU / ml, according to some reports up to 6.15) is produced by the pituitary gland. During pregnancy, the rate of beta hCG is several orders of magnitude higher than this figure.

The normal content of hCG in the blood by week of pregnancy;

Normally, after the cessation of the functioning of the corpus luteum, the concentration of chorionic gonadotropin gradually decreases, but in the third trimester of pregnancy, a repeated, less intense peak in the level of the hormone can be observed.

Previously, in medical practice, this phenomenon was considered one of the variants of the norm. Today, experts are more wary of the peak: an increase in the level of hCG after 11 weeks often indicates pathologies that threaten the health of the mother (trophoblastic disease), or placental insufficiency. The latter is often observed in the Rh-conflict of the organism of the pregnant woman and the fetus.

To monitor the health of the fetus, as well as to determine the presence of certain types of cancerous tumors, an analysis of the content of free β-hCG is used.

The concentration of free hCG can be indicated in nanograms per milliliter. The ratio of honey and mIU to ng is given below.

In men and in the absence of pregnancy in women, the level of unbound beta-subunit of gonadotropin does not exceed 43 mIU / ml (the maximum level of free hCG is 2 ng / ml).

The table below is indicative. It is up to the supervising physician to interpret the results, as these norms are average and may not be suitable for a particular pregnant woman due to special circumstances (some chronic diseases, multiple pregnancy, etc.).

Causes of low and high levels of hCG

Possible causes of elevated hCG levels in expectant mothers can be:

• multiple pregnancy (the level of hormone concentration is proportional to the amount);
• preeclampsia;
• severe early toxicosis;
• diabetes mellitus in a pregnant woman;
• prolonged gestation;
• discrepancy between the estimated and actual terms of pregnancy;
• taking hCG preparations or gestagens;
• chromosomal abnormalities in the fetus.

At non-pregnant women elevated levels of hCG in the blood may be associated with the onset of menopause ( normal rate increases to 9.5 mIU / ml), analysis less than 5 days after the abortion and trophoblastic diseases (molar mole, etc.).

Normally, after the birth of a child, chorionic gonadotropin is not detected in the urine, and its concentration in the blood quickly drops to normal values ​​​​(0-6.15 mIU / ml). If this does not happen even after 42 days after birth, gynecologists talk about trophoblastic pathology.

The reason for the increase in the level of gonadotropin can also be the presence of a cancerous tumor in the intestines, kidneys, and lungs. In men, an increased amount of hCG in the blood can also be associated with seminoma and testicular teratoma, in women with a hormone-producing neoplasm in the uterus.

A low level of hCG, unlike an elevated one, is only dangerous. Possible causes of the phenomenon may be:

• ectopic localization of the fetus;
• delayed fetal development;
• true overgrowth;
• risk of miscarriage;
• antenatal fetal death (when monitored in the 2nd-3rd trimester of pregnancy);
• chronic placental insufficiency (for example, due to the Rhesus conflict of the mother and fetus).

Of great importance is not only the result, but also the dynamics of hCG growth. For example, when it doubles on average 2 times a week, while normally the concentration of gonadotropin doubles every 2 days. With the threat of a miscarriage, the level of hCG drops rapidly (on average, by more than 50% of the normal value).

Features of the analysis for the level of hCG

Units

Measurement of the concentration of chorionic hormone is carried out in mIU / ml (international milliunits per milliliter), mU / ml or in mass units - nanograms per milliliter of biomaterial. Indicators honey and mIU are equivalent to each other. To convert ng / ml to generally accepted units, it is necessary to multiply the result obtained by 21.28.

Thus, 21.28 mU/ml = 21.28 mIU/ml = 1 ng/ml.

Result confirmation

From about 500 mIU / ml of hCG, the fetus can be detected on a transvaginal ultrasound. Early ultrasound diagnosis is used to clarify the location of the fetus, because. the concentration of placental gonadotropin also increases during ectopic pregnancy.

Biomaterial

Blood and urine can be used to study the level of hCG concentration. Home test strips and inkjet testers are less accurate than venous blood tests, but are cheap and easy to use. The sensitivity of the tests is indicated on the packaging.

Most of them show a positive result when the hCG concentration exceeds 25 mIU / ml, i.e. about 2 weeks after conception. More expensive tests are able to report pregnancy earlier - as early as 7-10 days after the fertilization of the egg.

However, in the early stages, experts advise resorting to a blood test, because. it will be possible to talk about a truly positive or negative result only after a few days after the delay.

Application in combination with other studies

Elevated levels of hCG in pregnant women may indicate fetal chromosomal diseases (most likely Down syndrome). To clarify the result, a comprehensive screening is carried out. In the first trimester, it includes the analysis of free β-hCG and PAPP-A (plasma protein A associated with pregnancy). A low protein level indicates a high risk of severe chromosomal abnormalities. In the second trimester, screening includes the study of three biochemical markers (hCG, alphafetoprotein and estriol-A).

In the absence of pregnancy, the hCG test can be used in combination with tests for tumor markers to determine cancerous growths.

How to get accurate results

The correctness of the result largely depends not only on the reagents and the correct work of the laboratory staff, but also on the preparation of the patient (patient) for the study. There are several rules that will minimize the error:

• venous blood analysis should be carried out strictly, if possible before 10 am;
• on the eve of the study, it is undesirable to eat fatty foods, drink alcohol and play sports;
• within 2-3 hours before blood sampling, it is necessary not to smoke or even drink water, and also to exclude stress;
• the patient or the patient must warn the laboratory assistant about all the drugs taken, especially hormonal ones;
• it is undesirable to donate biomaterial after X-ray, ultrasound, massage, physiotherapy and examinations.

This is important: for monitoring pregnancy, the dynamics of the increase in the level of hCG is very important, therefore, tests must be taken at the same time of day, under unchanged nutritional conditions.

human chorionic gonadotropin (abbreviated hCG, HCG, HCG in English language, HGL in Ukrainian) is a hormone that, in the normal state of the body, is produced exclusively during pregnancy. The hCG hormone is produced after conception - it is synthesized by a fertilized egg, and after it is formed trophoblast (this is the precursor of the placenta), this hormone is produced by its tissues. That is why the level of hCG is determined only after conception.

Chorionic gonadotropin consists of two different subunits - alpha and beta . At the same time, alpha is identical with subunits of alpha hormones. When it comes to hCG - what it is, its B-subunit is considered. It is important to understand, when considering what beta hCG is, that it is a unique subunit and therefore cannot be confused with other hormones. Speaking about the study on human chorionic gonadotropin, we mean that there is no difference between hCG and beta-hCG.

What is hCG during pregnancy? Its definition and interpretation is a very important stage in the diagnosis of a number of pathologies of both the fetus and the woman. In some conditions, which will be described in this article, hCG values ​​​​are either greatly reduced or increased. Considering what kind of analysis it is, it must be taken into account that when small deviations this study has no diagnostic value from the norm. Therefore, some diseases and conditions future mother (prolongation of pregnancy , intrauterine infection, chronic placental insufficiency ) is determined by other methods.

After the results of hCG have been obtained, they are deciphered in dynamics, since each woman's hCG level during pregnancy changes in her own way. Therefore, one result cannot be used to judge the situation as a whole.

It is important that the result of the analysis of hCG for pregnancy must be considered by a qualified specialist. After all, decoding hCG test is very important, as it allows you to correct some problems of fetal development.

Since the free beta subunit of gonadotropin is unique, the test that determines the rate of hCG during pregnancy is also called beta-hCG. Normal - if during pregnancy HCGb appears in the blood a few days after conception. But, nevertheless, if, for example, hCG is 8, what it means, after the first analysis, it is definitely impossible to say. A repeat test will be required to confirm pregnancy. In general, the fb-HCG rate is a very important indicator of fetal development.

When handing over hCG to Invitro, Hemotest, Helix and other clinics, a woman needs to understand what kind of indicator it is, when such a test shows pregnancy, etc. This will be discussed in the article below.

What is HCG for?

When determining HCGb indicators, you need to understand why human gonadotropin is needed. Wikipedia says the following:

• this hormone at the beginning of pregnancy stimulates the synthesis process and;
• prevents disappearance corpus luteum ;
• prevents aggression maternal organism against fetal cells;
• initiates physiological and anatomical changes in the body of a pregnant woman;
• stimulates the adrenal glands and gonads of the fetus;
• participates in the process of sexual differentiation in male fetuses.

Why is this analysis ordered?

Analysis for women is prescribed for the purpose of:

• early diagnosis of pregnancy;
• monitoring the dynamics of how the pregnancy proceeds;
• definition of malformations (fetal anatomy);
• development exceptions ectopic pregnancy ;
• the need to assess whether the artificial was completely carried out;
• establishing that there is a threat;
• diagnostics and tumors .

For male patients, such an analysis is necessary to diagnose testicular tumors .

HCG levels during pregnancy

The function of chorionic gonadotropin in the body is very important. Its indicators in the early stages begin to increase, as it is produced by a fertilized egg. It is hCG that makes it possible for pregnancy to develop, since it starts all the processes necessary for bearing a baby.

Already 9 days after ovulation, hCG can be determined in the blood plasma. That is, even when the fertilized egg has invaded the endometrium, there is a slow increase in the indicators of this hormone. And if its low level is determined in the early stages, then the concentration doubles every two days. What exactly should be its level in a certain week, how hCG should grow, slow or fast growth is noted, you can find out from the corresponding tables.

The growth of hCG during pregnancy occurs up to 8-10 weeks from the last menstruation, when its peak is noted - 50,000-10,000 IU / l. Further, the level of the hormone begins to decrease, by 18-20 weeks it is already reduced by half. Then the content of hCG remains stable for the entire duration of pregnancy.

Gonadotropin during pregnancy is excreted from the body by the kidneys, therefore, it is excreted in the urine. It can be determined by conducting a urinalysis, in the range of 30-60 days after the last menstruation. The highest rates are noted for 60-70 days. That is why, when hCG begins to be produced, you can do a pregnancy test strip or other urinary tests.

HCG levels during pregnancy later dates can reach repeated peak levels. Previously, such doctors considered a variant of the norm. However, it has now been proven that elevated hCG in the later stages may indicate a developmental pathology. In particular, a high hormone level in the last weeks of gestation sometimes means that there is a reaction of the placenta to placental insufficiency in the case of Rhesus conflict .

Therefore, it is necessary to identify this disease in a timely manner and treat it.

The main signs of hydatidiform mole are:

• Constant, indomitable vomit , much more painful than with the usual.
• Uterine bleeding (severe daubing) at an early stage.
• The size of the uterus is larger than normal at this time.
• Symptoms preeclampsia (sometimes).
• Trembling fingers, palpitations, weight loss (rare).

When the signs described above are noted, it is important to consult a gynecologist, undergo an ultrasound scan and be tested for hCG.

If the pregnancy develops normally, then the rate of this hormone rarely increases more than 500,000 IU / L. There is an approximate calculation of hormone norms for each period. But if a cystic drift develops, the level of hCG is different, several times higher than these norms.

To cure a hydatidiform mole, the entire trophoblast must be removed from the uterus. For this, curettage or other surgical interventions are carried out.

It may happen that a benign hydatidiform drift turns into malignant chorionic carcinoma . As a rule, with this tumor, metastases appear very quickly. But it responds well to treatment with chemotherapy .

There are the following indications for chemotherapy:

• HCG levels above 20,000 IU/L one month after the mole was removed.
• An increase in the level of this hormone after the mole has been removed.
• Metastases to other organs.

chorioncarcinoma

chorioncarcinoma may appear both after hydatidiform mole, and after childbirth or abortion. If a woman develops this disease, then 40 days after the pregnancy has ended, the level of hCG has not fallen, but its increase is noted. There may also be uterine bleeding, signs that indicate metastases. In such a situation, there are indications for chemotherapy, surgical intervention. In the future, the patient should be under observation. How long it should last, the doctor decides.

The use of drugs with human chorionic gonadotropin

Like all human hormones, the level of human chorionic gonadotropin can depend on various factors. So, the result of the tests is affected by whether a woman takes drugs containing human gonadotropin orally.

As a rule, such drugs are prescribed to women during, as well as during the period when preparations for IVF are underway, in order to increase the level of the hormone.

In rare cases, such drugs are taken if there is a threat of miscarriage. In any case, if a woman uses such medications, then before taking any measurements and analyzes, you need to warn the doctor about this.

Taking a variety of drugs, many women are interested in whether they can affect the performance of this hormone. For example, it is often asked whether to the hCG level. According to experts, Duphaston may slightly affect the level of this hormone, since this drug controls the level progesterone . However, if the hCG norms do not comply, this cannot be attributed to the effect of the drug, since we can talk about a pathological condition.

The level of this hormone is not affected.

Hormonal drugs, the active ingredient of which is human chorionic gonadotropin, these are Profazi , Humegon , Horagon , Choriogonin , Menogon . They restore the ovulatory process, activate the hormonal activity of the corpus luteum. At what size of the follicle an injection is given, the doctor determines.

Initially, studies are carried out on hormones, their norm in women and deviations. If there are certain deviations, in particular, progesterone is below normal, what this means, the doctor will explain during the consultation and prescribe a specific treatment.

If necessary, to stimulate ovulation, hCG injections are prescribed from 5000 to 10000 IU, in order to maintain pregnancy - from 1000 to 3000 IU. Individual dose selection is important. Therefore, if an injection of 10,000 was given, when ovulation, if an injection of 5,000 was given, after how much ovulation, the specialist will explain.

Currently, human chorionic gonadotropin is also used by athletes, since under its influence it increases in the male body.

False positive test result

Those who are interested in how long a pregnancy test shows for this hormone should take into account that in some situations, tests can be false positive.

This happens in the following cases:

• Some experts argue that when taking oral contraceptives, the level of the hormone may increase. However, there is no proven evidence that contraception affects hCG.
• As a rule, after childbirth or abortion, the level of the hormone decreases for seven days. In some cases, the doctor waits 42 days, after which tests are taken, and he can make a diagnosis. If the analysis shows that hCG has not decreased or increased, then we can talk about a trophoblastic tumor.
• The level may remain elevated when metastases occur. chorioncarcinoma , hydatidiform mole .
• Other tumors can also develop from germinal tissues, but they rarely give an increase in the level of the hormone. Therefore, in the presence of education in the brain, stomach, lungs and a high level of chorionic gonadotropin, first of all, there is a suspicion of trophoblastic tumors with metastases.

Thus, the hCG rate in non-pregnant women should not be higher than those that are normal. The norm of hCG in non-pregnant women is from 0 to 5. The level of this hormone in a non-pregnant woman may be higher in the first days after an abortion, when taking certain medications, and also with the development of certain pathological conditions.

Immunity against hCG

In rare cases (units) in the female body are produced to chorionic hormone. They are an obstacle to the normal attachment of a fertilized egg in the uterus and its subsequent development.

Therefore, if in two or more cases the pregnancy ended in a spontaneous miscarriage, it is important to take an analysis to determine antibodies to hCG and find out if there are any specific abnormalities. If the result is positive, treatment is carried out during the first trimester.

The woman is assigned glucocorticoids and low molecular weight heparins . However, it is important to consider that organisms that produce antibodies to hCG are rare. Therefore, in the absence of pregnancy, you must initially go through all the studies and exclude the influence of other factors on women's and men's health.

conclusions

Thus, an analysis for hCG is a very important study during the period of bearing a baby. It is quite understandable that after receiving the results of the studies, patients have many questions. For example, why hCG is growing, but not doubling, how to correctly decipher hCG according to DPO, etc., does fibroids affect hormone levels, etc. You need to ask a gynecologist about everything, who will help decipher the tests and give comprehensive answers to all questions.

Description

Method of determination Linked immunosorbent assay.

Material under study Serum

Home visit available

Specific pregnancy hormone.

Glycoprotein is a dimer with a molecular weight of about 46 kDa, synthesized in the placental syncytiotrophoblast. HCG is made up of two subunits: alpha and beta. The alpha subunit is identical to the alpha subunits of the pituitary hormones TSH, FSH, and LH. The beta subunit (β-hCG) used for the immunometric determination of the hormone is unique.

The level of beta-hCG in the blood as early as 6-8 days after conception makes it possible to diagnose pregnancy (the concentration of β-hCG in the urine reaches the diagnostic level 1-2 days later than in the blood serum).

In the first trimester hCG pregnancy provides the synthesis of progesterone and estrogens, necessary to maintain pregnancy, by the corpus luteum of the ovary. HCG acts on the corpus luteum like a luteinizing hormone, that is, it supports its existence. This happens until the "fetus-placenta" complex acquires the ability to independently form the necessary hormonal background. In the male fetus, hCG stimulates the Leydig cells that synthesize testosterone, which is necessary for the formation of male reproductive organs.

The synthesis of hCG is carried out by trophoblast cells after implantation of the embryo and continues throughout pregnancy. In the normal course of pregnancy, between 2 - 5 weeks of pregnancy, the content of β-hCG doubles every 1.5 days. The peak concentration of hCG falls on the 10th - 11th week of pregnancy, then its concentration begins to slowly decrease. At multiple pregnancy the content of hCG increases in proportion to the number of fruits.

Decreased concentrations of hCG may indicate an ectopic pregnancy or threatened abortion. Determination of the content of hCG in combination with other tests (alpha-fetoprotein and free estriol at 15-20 weeks of pregnancy, the so-called " triple test”) is used in prenatal diagnosis to identify the risk of fetal abnormalities.

In addition to pregnancy, hCG is used in laboratory diagnostics as a tumor marker for tumors of trophoblastic tissue and germ cells of the ovaries and testes that secrete chorionic gonadotropin.

Early diagnosis of pregnancy: determining the level of hCG

What is HCG?

HCG (human chorionic gonadotropin) is a special pregnancy hormone, which is an important indicator of the development of pregnancy and its deviations. Chorionic gonadotropin is produced by cells of the chorion (shell of the embryo) immediately after its attachment to the wall of the uterus. Based on a blood test for chorionic gonadotropin, the doctor determines the presence of chorionic tissue in the body, and hence the onset of pregnancy in a woman.

When can I conduct a study to determine the level of hCG?

Determining the level of human chorionic gonadotropin in the blood is the most reliable method early pregnancy detection. Chorionic gonadotropin appears in a woman's body from 5 to 6 days after fertilization. A common rapid pregnancy test that every woman can use at home is also based on the determination of human chorionic gonadotropin in the urine, but the necessary level of this hormone in the urine to diagnose pregnancy is reached a few days later.

In the absence of any pathology, in the first weeks of pregnancy, the level of the hormone doubles every 2 days, and its maximum concentration is reached by 10-11 weeks of pregnancy. After 11 weeks, the level of the hormone gradually goes down.

An increase in the level of human chorionic gonadotropin during pregnancy can occur with:

multiple pregnancy;

toxicosis, gestosis;

maternal diabetes;

fetal pathologies, Down syndrome, multiple malformations;

incorrectly established gestational age;

taking synthetic gestagens, etc.

Elevated values ​​can also be seen within a week when taking an analysis after the abortion procedure. A high level of the hormone after a mini-abortion indicates a progressive pregnancy.

Low levels of human chorionic gonadotropin during pregnancy can mean miscalculation of the pregnancy or be a sign of serious disorders, such as:

ectopic pregnancy;

non-developing pregnancy;

delay in fetal development;

the threat of spontaneous abortion;

fetal death (in the II-III trimester of pregnancy).

Determining the level of chorionic gonadotropin is included in a triple test study, the results of which can be used to judge the presence of some anomalies in the development of the fetus, but an accurate diagnosis cannot be made. The study only allows you to identify women at risk. In this case, women will need to make a serious additional examination.

What is the role of the hCG hormone in the human body?

In addition to establishing the fact of pregnancy, by quantitative determination of the level of this hormone, one can judge the nature of the course of pregnancy, the presence of multiple pregnancy.

The most important task of human chorionic gonadotropin is to maintain the pregnancy itself. Under its control, the synthesis of the main hormones of pregnancy: estrogen and progesterone. In the first trimester, until the placenta is fully formed (up to 16 weeks), human chorionic gonadotropin maintains the normal functional activity of the corpus luteum, namely, the production of progesterone.

Another important function of human chorionic gonadotropin is to stimulate ovulation and maintain the viability of the corpus luteum.

When does a doctor prescribe an hCG test?

Beyond diagnostics early dates pregnancy, chorionic gonadotropin determine:

among women -

to detect amenorrhea;

exclusion of the possibility of ectopic pregnancy;

to assess the completeness of artificial abortion;

for dynamic monitoring of pregnancy;

with the threat of miscarriage and suspected non-developing pregnancy;

for the diagnosis of tumors - chorionepithelioma, cystic drift;

for prenatal diagnosis of fetal malformations;

in men -

for the diagnosis of testicular tumors.

How to take a blood test for the hCG hormone?

The independent laboratory INVITRO offers to undergo a laboratory test to determine the level of human chorionic gonadotropin.

The analysis is given by taking blood from a vein, preferably in the morning and on an empty stomach. A laboratory test is recommended to be carried out no earlier than 4-5 days of delayed menstruation, and can also be repeated after 2-3 days to clarify the results. To identify fetal pathology in pregnant women, it is recommended to take an analysis from the 14th to the 18th week of pregnancy.

In the complex diagnosis of fetal malformations, it is also recommended to take tests to determine the following markers: AFP (alpha-fetoprotein), E3 (free estriol), as well as an ultrasound scan.

Limits of determination: 1.2 mU/ml-1125000mU/ml

Training

It is preferable to take blood in the morning on an empty stomach, after 8-14 hours of a night fasting period (you can drink water), it is permissible in the afternoon 4 hours after a light meal.

On the eve of the study, it is necessary to exclude increased psycho-emotional and physical exercise(sports training), drinking alcohol, one hour before the study - smoking.

The sensitivity of the method in most cases makes it possible to diagnose pregnancy already on the first or second day of missed menstruation, but due to individual differences in the rate of synthesis of β-hCG in women, it is better to conduct a study no earlier than a 3-5 day delay in menstruation in order to avoid false negative results. In case of doubtful results, the test should be repeated twice with an interval of 2-3 days. When determining the completeness of the removal of an ectopic pregnancy or abortion, the study of β-hCG is carried out 1-2 days after the operation to exclude a false positive result.

Interpretation of results

The interpretation of test 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. An accurate diagnosis is made by the doctor, using both the results of this examination and the necessary information from other sources: history, results of other examinations, etc.

Units of measurement in the INVITRO laboratory: honey/ml.

Alternative units of measure: U/l.

Unit conversion: U / l \u003d honey / ml.

Reference values

Pregnant women

Values ​​ranging from 5 to 25 mU / ml do not allow to confirm or deny pregnancy and require a re-examination after 2 days.

Increasing hCG levels

Men and non-pregnant women:

1. chorioncarcinoma, recurrence of chorioncarcinoma;
2. cystic drift, recurrence of cystic drift;
3. seminoma;
4. testicular teratoma;
5. neoplasms of the gastrointestinal tract (including colorectal cancer);
6. neoplasms of the lungs, kidneys, uterus, etc.;
7. the study was conducted within 4 - 5 days after the abortion;
8. taking hCG drugs.

Pregnant women:

1. multiple pregnancy (the level of the indicator increases in proportion to the number of fetuses);
2. prolonged pregnancy;
3. discrepancy between the real and the established gestational age;
4. early toxicosis of pregnant women, preeclampsia;
5. maternal diabetes;
6. fetal chromosomal pathology (most often with Down syndrome, multiple fetal malformations, etc.);
7. taking synthetic gestagens.

Decreased hCG levels

Pregnant women. Alarming level changes: inconsistency with the gestational age, an extremely slow increase or no increase in concentration, a progressive decrease in the level, more than by more than 50% of the norm:

1. ectopic pregnancy;
2. non-developing pregnancy;
3. the threat of interruption (the level of the hormone decreases progressively, by more than 50% of the norm);
4. chronic placental insufficiency;
5. true prolongation of pregnancy;
6. antenatal fetal death (in II - III trimesters).

False negative results (non-detection of hCG during pregnancy):

1. the test was performed too early;
2. ectopic pregnancy.

Attention! The test has not been specifically validated for use as a tumor marker. HCG molecules secreted by tumors can have both normal and altered structure, which is not always detected by the test system. The results of the test should be interpreted with caution, in comparison with clinical data and the results of other types of examination, they cannot be considered as absolute evidence of the presence or absence of the disease.