HCG is human chorionic gonadotropin, which is a hormone produced by the fetus immediately after conception. Subsequently, the placenta is responsible for its reproduction. Therefore, the presence of a certain amount of this hormone in a woman’s blood or urine will clearly indicate that embryo implantation has occurred.
Two subunits are included in the structure of hCG - alpha and beta. Alpha is responsible for the production of other hormones and is not used to determine whether a woman is pregnant or not, so the beta subunit is used for this. If the pregnancy proceeds normally, then the beta subunit of hCG in the body of the expectant mother begins to appear approximately five to seven days after conception. A week after conception, the hCG concentration is more than 50 mIU/ml. The maximum level of hCG in urine is 200 mIU/ml (this indicator is observed in the first trimester of pregnancy).
It is important to note that tests of non-pregnant, completely healthy women may also contain hCG, but its level will be extremely low and insufficient to determine the presence of pregnancy. In addition, if the pregnancy is ectopic, the level of the gonadotropin hormone will be much lower, in contrast to a normal pregnancy.
The level of the hormone (carried out along with other common tests) is determined by doctors at approximately 15-20 weeks of pregnancy in order to identify the risks of fetal development abnormalities during the process of perinatal diagnosis. This is an extremely important analysis at these times, which allows you to obtain very effective research results that really help to detect in time all the deficiencies in the development of the fetus and take the necessary measures to eliminate them.
In some cases, hCG is used for diagnostic purposes as an oncological marker for the presence of malignant neoplasms of the trophoblastic tissue of the testes and ovaries, which are formed by human chorionic gonadotropin. This method is not used very often, but in a number of situations it is relevant.
HCG - description
The abbreviation, consisting of an incomprehensible three letters, hCG, stands for human chorionic gonadotropin. This is a protein hormone produced by the tissue of the chorion (embryo) after the embryo attaches to the wall of the uterus. HCG appears within a few days after fertilization of the egg has occurred. A certain concentration of hCG in a woman’s urine and blood is confirmation of the presence of pregnancy, and in the future – an indicator of its development.
Results and interpretation of hCG
As you know, pregnancy occurs with the assistance of luteinizing and follicle-stimulating hormones. Like them, the hCG hormone belongs to the gonadotropic hormones, but has a different chemical structure, which includes more than 180 amino acids, as well as the alpha-hCG and beta subunit, which becomes a decisive factor in the analysis. This difference made it possible to create a standard test that allows one to determine pregnancy by the days after ovulation.
When does hCG begin to be produced? Surprisingly, hCG begins to be produced from the first hours of conception, and in the period from 8 to 10 weeks its concentration increases many times. Subsequently, its level gradually decreases.
How does hCG work?
This hormone promotes the development of pregnancy by maintaining the functions of the corpus luteum, which is formed in the ovary during ovulation. The corpus luteum, in turn, produces progesterone, which creates favorable conditions in the uterus for the development of the embryo.
HCG during pregnancy promotes the formation of the placenta, which is subsequently responsible for the production of human chorionic gonadotropin.
The action of standard tests that allow early detection of pregnancy is based on the interaction of the chemical coating of the test strip with the protein contained in the woman’s urine.
On what day can testing be carried out? Given the lower concentration of hCG in urine, such tests are recommended when menstruation is delayed by more than 3 days or 2 weeks after fertilization of the egg has occurred. The best way to determine the level of hCG is in morning urine. However, if the delay exceeds one week, the test can be performed at any time of the day or night.
HCG is most active during pregnancy during its first trimester. It promotes not only the production of progesterone, but also other sex hormones - estradiol and estriol, which the body requires for its normal course.
Protein is determined not only in urine, but also in blood serum. At the same time, its content in the blood is more significant and makes it possible to determine pregnancy within a week after fertilization of the egg.
In the body of a woman expecting the birth of a baby, hCG includes the following functions:
- providing a stimulating effect on the corpus luteum of the ovary, which produces progesterone;
- preventing the maturation of new follicles in the ovary;
- suppression of the action of immune cells aimed at rejecting fetal cells;
- stimulating the work of the adrenal cortex of the unborn baby;
- assisting in the formation of male genital organs in the male embryo and stimulating the production of testosterone by the testicles.
HCG is found in small concentrations in the blood of everyone, regardless of what gender a person is. This factor is explained by the fact that this protein is synthesized in small quantities by the pituitary gland.
Functions
The content of gonadotropin is relatively small, but it has a number of critical responsibilities on which the lives of interconnected organisms depend.
During the production of hCG, the following processes occur:
- Formation of the reproductive and endocrine glands of the fetus.
- Physiological preparation of a woman’s body for the upcoming birth.
- Preventing the disappearance of the temporary corpus luteum - a temporary gland that produces progesterone, necessary for the proper course of pregnancy.
- Suppression of further maturation of follicles, introducing them into a kind of inactive state while carrying a baby.
- Reducing the mother’s immune responses to prevent rejection of a partially foreign embryo in her body.
How does hCG change during pregnancy?
The level of hCG during pregnancy begins to actively increase at 3 weeks from conception. During this period, the hormone level doubles every 2-3 days, continuing to grow relentlessly until 11-12 weeks. A decrease in protein concentration occurs by week 12, and remains virtually unchanged until week 22. Then the hCG level begins to rise again until childbirth, but not so intensely.
Unlike home tests, in a laboratory setting the level of human chorionic gonadotropin is determined by drawing blood. In this case, a venous hCG test to determine pregnancy can be taken a week after the expected day of the onset of menstruation.
In what cases is a urine test for hCG prescribed?
For women, a urine test to determine protein concentration may be prescribed in the following cases:
- to determine pregnancy in the early stages;
- if it is necessary to monitor pregnant women with a history of spontaneous abortions or fetal death;
- during observation to exclude ectopic pregnancy;
- in case of prolonged absence of menstruation in cases not related to pregnancy;
- to identify hormone-dependent tumors;
- for the purpose of intrauterine detection of pathologies in the fetus;
- when there is a threat of spontaneous abortion;
- to assess the condition of a woman who has undergone a medical termination of pregnancy;
- if you suspect a frozen pregnancy;
- in case of severe uterine bleeding.
Urine tests are also carried out at home, which, depending on the test system used, makes it possible to determine not only the presence of pregnancy, but also the duration. For example, an hCG reading of 69 indicates a period of 1-2 weeks.
HCG determination in men is carried out according to the following indications:
- suspicion of the presence of a hormone-dependent tumor developing in the testicles or other organs;
- to achieve sports performance.
HCG table for men and women
In the latter case, we are talking about the use of anabolic steroids. These hormonal drugs help increase muscle mass, but their disadvantage is the ability to block testosterone production. Therefore, after stopping steroids, athletes often have to resort to the use of hCG, which stimulates the natural production of testosterone.
Decoding the results
Deviations from the norm over 20% indicate pathological development of the fetus. However, each specific case must be studied individually, since the characteristics of the body are different for everyone. That is why the analysis must be deciphered by a competent specialist who will carefully study the situation and, if necessary, prescribe a repeat analysis.
When confirmation of the pathological process is received, the doctor will conduct additional diagnostics, establish an accurate diagnosis and prescribe competent treatment.
If hCG is produced without deviations and the test results are normal, we can with a high probability talk about the absence of pathology in the course of pregnancy. But if deviations are nevertheless identified, you should not immediately succumb to fear and panic. It is necessary to contact a highly qualified specialist who will correctly interpret the results obtained and prescribe competent treatment.
It is important to choose a proven and reliable clinic for testing. After all, a guarantee of the most accurate research can only be in the case of high-tech equipment in the laboratory and the presence of highly qualified specialists.
Normal indicators
For men and women who are not carrying a child, it is believed that the normal value can start from hCG 0, and its maximum permissible value is hCG 15. They are measured in nmol per 1 ml of blood. And in urine this indicator can be zero or a maximum of 5 mU per 1 ml of urine. Exceeding this indicator may indicate the development of a hormone-dependent tumor in the body.
Indicators of hCG in urine corresponding to the norm
How much is the norm of the hormone? Below is a table that indicates the hCG norm in urine in honey per 1 ml, calculated from conception, and determined based on the week of pregnancy.
| From first to second | from 19 to 145 |
| From second to third | from 111 to 3640 |
| From third to fourth | from 1090 to 17600 |
| From fourth to fifth | from 2740 to 59600 |
| From fifth to sixth | from 23500 to 137000 |
| From sixth to seventh | from 29900 to 222000 |
| From seventh to eighth | from 30500 to 266000 |
| Eighth to ninth | from 54700 to 268000 |
| From ninth to tenth | from 25900 to 234000 |
| From ten to eleven | from 46200 to 238000 |
| From eleven to eighteen | from 16500 to 92700 |
| Eighteenth to twenty-seventh | from 8540 to 58500 |
If the pregnancy is ectopic, then the concentration of protein in the urine increases much more slowly than in standard cases. And at a period of 3 to 7 weeks, the hCG rate begins to decrease.
If hCG during pregnancy begins to increase from conception, and its normal development is confirmed by ultrasound examination, but then the level of the hormone decreases sharply, it means that there is a threat of self-termination of pregnancy, or the fetus has died.
How does hCG rise during pregnancy?
HCG levels in the blood correspond to the norm
Human chorionic gonadotropin, like any other hormone, is sensitive to any manipulation. Therefore, a reliable laboratory test result can only be obtained if certain rules are followed.
- You should not eat food 10 hours before donating blood.
- The day before the test, it is necessary to exclude sexual contact.
- On the eve of donating blood, you should avoid intense physical activity, overheating and hypothermia, as well as stressful situations.
The study is carried out no earlier than 7 days after the expected conception. And obtaining the most reliable results is possible only with three blood samples taken at an interval of 2 days.
Serum hCG readings that correspond to the norm for pregnant women and calculated from conception are as follows.
| Third | from 5 to 50 |
| Fourth | from 5 to 426 |
| Fifth | from 18 to 7340 |
| Sixth | from 1080 to 56500 |
| From seventh to eighth | from 7650 to 229000 |
| From ninth to twelfth | from 25700 to 288000 |
| From thirteenth to sixteenth | from 13300 to 254000 |
| From seventeenth to twenty-fourth | from 4060 to 165400 |
| From twenty-fifth to fortieth | from 3640 to 117000 |
A decrease in the concentration of hCG in the blood during pregnancy can occur in the following cases:
- unreliable calculation of gestational age;
- the fetus is located outside the uterus;
- the fetus froze;
- threat of spontaneous miscarriage.
An hCG level during pregnancy that exceeds the standard indicates the following:
- before pregnancy, the woman took medications containing a synthetic analogue of human chorionic gonadotropin;
- the pregnancy period is determined incorrectly;
- multiple pregnancy;
- genetic pathologies of the fetus;
- hormone-dependent tumors.
When taking the test, you should take into account the difference in hCG in the blood and urine: there is 1.5-2 times more protein in the blood.
Indications for analysis
At what stage can an ectopic pregnancy be detected by ultrasound?
- Suspicion of a malignant tumor of the internal genital organs.
- Lack of menstruation.
- Assessment of the quality of abortion performed using medications in a hospital setting.
- Vaginal bleeding of unknown origin.
- Confirmation or denial of pregnancy 5–7 days after expected fertilization.
- High probability of miscarriage.
- Tracking the dynamics of gonadotropin levels by day from conception.
