Pregnancy and hCG. Normal hCG levels by week

Human chorionic gonadotropin (hCG) is considered to be a hormone that accompanies the full process of pregnancy by a woman. Indeed, the role of hCG in maintaining pregnancy is enormous, but this is not the only purpose of the hormone. Blood flow analysis for hCG is done not only for pregnant women, but also for women who are not carrying a child, and this test is also prescribed for men. For what purpose is the hCG analysis performed? Decoding the results will show what this laboratory test detects.

HCG during pregnancy - normal occurrence

Human chorionic gonadotropin begins to be produced after the embryo has been implanted into the walls of the tag, and this occurs 6–8 days after fertilization of the egg by the sperm.
HCG is one of the most important indicators of the normal course of pregnancy. Just like other hormones (follicle-stimulating and luteinizing), it belongs to a number of gonadotropic hormones. The only difference between them is the different amino acid sequence. Test systems for determining pregnancy are based on the detection of human chorionic gonadotropin, namely its beta subunit in the urine. This is due to the fact that the hormone is excreted from the body in the urine.

In Vitro Fertilization

During the IVF procedure, it is important to control hormonal levels, since the natural process of pregnancy is disrupted. The doctor must monitor hormonal levels in order to adjust the amount with medication if there is a deficiency of the hormone. For medical reasons, an HCG injection is prescribed in the IVF protocol. Injections help restore ovulation. The drug is dosed individually.

After embryo transfer, an hCG test is performed two weeks later. This is the most reliable way to establish the fact of pregnancy. HCG is monitored weekly. If the hormone increases, then you should think about the birth of a new life.

Hormone control is indicated throughout the entire period of bearing a child, since after reproductive technologies the risk of miscarriage increases. To assess the characteristics of pregnancy after IVF, women are advised to monitor hormone levels on a daily basis.

During the period from the tenth to the fourteenth week of pregnancy, screening is carried out to exclude chromosomal abnormalities. Ultrasound and hCG studies are recommended for women at risk:

Spouses are relatives
A large number of miscarriages in previous attempts to carry a baby to term
Hereditary factor
Woman's age over 35 years

An increase in gonadotropin hormone levels often indicates Down syndrome. To identify abnormalities in the development of the embryo, an analysis is carried out for the presence of genetic defects. Traditional methods of genetic analysis include ultrasound and hCG testing. In the interval of 10 – 14 weeks, pathological abnormalities in the development of the fetus are clearly visible. If the doctor doubts the normal course of pregnancy, he will refer you for additional tests: amniotic fluid testing, chorionic villus biopsy, umbilical cord blood.

Human chorionic gonadotropin is a special hormone. This is an ideal marker of the oncological process. For some types of malignant tumors, the sensitivity of the hormone is 100% (tumor of the placenta, ovarian carcinoma, tumor processes in the uterus, intestinal cancer).

Properties of hCG

Human chorionic gonadotropin stops the process of resorption of the corpus luteum of the ovary, which remains after the rupture of the follicle and the release of the egg, ready for fertilization. After all, it is in it that the progesterone and estrogen necessary for the normal course of pregnancy are synthesized.
HCG has corticotropic properties, that is, it stimulates the production of steroid hormones by the adrenal cortex. Steroids help the female body cope with the stress that pregnancy poses to it. They also have immunosuppressive qualities that prevent rejection of the fetus as a foreign organism.
The hCG hormone has a beneficial effect on the growth and development of the placenta by improving its nutrition and functional activity. Human chorionic gonadotropin also affects the chorion (the outer membrane of the fetus), increasing the number of its villi.
Changes in the anatomy and physiology of the female body during pregnancy are also directly related to the effects of hCG.
It takes part in the differentiation of the male fetus, namely, it induces the synthesis of testosterone by the testes.

The structure and role of hCG in a woman’s body

Human chorionic hormone (hCG) is produced in both women and men. In a woman's body it is produced by the pituitary gland. In the male body, hCG synthesis occurs in the testicles. Its concentration is insignificant and never exceeds five milliinternational units in one milliliter of blood.

HCG in its structure is a glycoprotein with a fairly large molecular weight. It consists of two particles of unequal importance: α and β. The α subunit is found not only in hCG, but also in other gonadotropic and thyroid hormones. The component that distinguishes hCG from other gonadotropes is its β-substance. Thanks to it, such properties of chorionic hormone as immune specificity and biological activity are manifested.

The biological activity of hCG is similar to that of follicle-stimulating and luteinizing hormones. It is able to bind to both types of gonadotropin receptors. HCG exhibits a more pronounced luteinizing activity than follicle-stimulating activity.

After conception, hCG begins to be produced not only by the pituitary gland, but also by the placenta. The activity of placental hCG is much stronger than that of the pituitary hCG. It is he who contributes to the persistence of pregnancy. Normally, the corpus luteum formed at the site of the burst follicle resolves after two weeks. If the egg is fertilized and implanted, then from the first days of pregnancy the syncytiotrophoblast begins to produce hCG, which prevents the corpus luteum from dissolving.

It continues to function for two weeks and synthesizes progesterone and estrogen, which support pregnancy. Only after the placenta itself becomes capable of producing these hormones does the need for the corpus luteum disappear, and it is eliminated on its own. HCG has the ability to stimulate the synthesis of small amounts of estrogens and weak androgens by the corpus luteum.

It also has an immunosuppressive effect, which allows you to maintain pregnancy. Since hCG causes physiological hyperplasia of the adrenal cortex, during pregnancy the amount of corticosteroid hormones in a woman’s blood increases. Glucocorticoids increase a pregnant woman's resistance to the stress that pregnancy itself causes. In addition, they are powerful immunosuppressants, which prevents the fetus from being rejected.

The hCG level increases day by day. This contributes to the good development of the placenta, improving its trophism and maintaining functional activity. When the concentration of hCG increases over the weeks, the number of chorionic villi increases in the correct proportion. However, there are situations when the level of hCG increases day by day in the absence of pregnancy or in men. In this case, you need to think about ectopic hCG, the cause of which may be malignant neoplasms.

Injection of exogenous hCG in the middle of the female cycle leads to an increase in the ovarian synthesis of progesterone and estrogen, then ovulation begins, and then luteinization of the burst follicle. This contributes to the successful fertilization of the egg and the progression of pregnancy. Administration of hCG to a man leads to increased spermatogenesis and testosterone synthesis, which increases his fertility. However, an increase in hCG levels over the weeks in a man can occur if he has a tumor of the testes.

HCG during pregnancy: normal

The normal level of human chorionic gonadotropin in the blood of a non-pregnant healthy woman ranges from 0-5 mU/l. The same level is found in the blood of men.

In the case when the course of pregnancy is physiological (normal), the concentration of hCG gradually doubles with an interval of two days. Its maximum value is determined in the period of 8–10 weeks of pregnancy and is up to 291 thousand honey units/ml. Next, the hormone level quickly decreases, reaching a value of about 4 – 80 thousand mU/ml during pregnancy 16 – 21 weeks. Until the moment of birth, approximately the same hCG value is maintained.

HCG during pregnancy - norm by week:

from 1 to 2 weeks of pregnancy - 25 - 156 mU/ml
from 2 to 3 weeks of pregnancy – 101 – 4870 mU/ml
from 3 to 4 weeks of pregnancy – 1110 – 31500 mU/ml
from 4 to 5 weeks – 2560 – 82300 mU/ml
from 5 to 6 weeks – 23100 – 151000 mU/ml
from 6 to 7 weeks – 27300 – 233000 mU/ml
after 7 weeks and before 11 weeks – 20900 – 291000 mU/ml
from 11 to 16 weeks – 6140 – 103000 mU/ml
from 16 to 21 weeks – 4720 – 80100 mU/ml
from 21 to 39 weeks of pregnancy – 2700 – 78100 mU/ml

In some situations, it is necessary to determine hCG during pregnancy. The norm indicates the correct course of pregnancy.

Tests for the content of human chorionic gonadotropin can be taken at the IVF Center clinic in Smolensk.

Interpretation of hCG readings in pregnant women

HCG analysis and interpretation among women registered during pregnancy may show increased and decreased levels of human chorionic gonadotropin. Both clinical conditions are very dangerous for both the pregnant woman and the child in the womb. Deciphering the hCG analysis, that is, an increase or decrease in the value of chorionic hormone should occur taking into account the standards established for each individual period of gestation. A reduced hCG ratio in the blood of women during pregnancy does not bode well.

A decrease in chorionic hormone levels in pregnant women may indicate the following pathologies:

Ectopic fertilization.
Threat of spontaneous miscarriage.
Incorrect development or freezing of the embryo.
Overmaturity of the child due to prolongation of the gestation period.
Fetoplacental insufficiency.

An increased level of hCG in the blood of women preparing to become mothers occurs:

From the use of gestagens.
When bearing several fruits.
If the pregnancy date is incorrectly stated.
If a woman has diabetes.
If there is a possibility of a chromosomal abnormality of the fetus.
When pregnancy is delayed beyond 42 weeks.
When a severe degree of toxicosis develops, which threatens complications in the form of impaired renal function (nephropathy), and as a result, severe swelling. And in addition they threaten with weight gain and high blood pressure.

In addition, a complicated condition of gestosis, called eclampsia, is dangerous due to the appearance of convulsive seizures. If a course of therapy is not carried out in a timely manner, the consequences can be disastrous - the death of the mother or child. In view of this, pregnant women are usually recommended to regularly test for hCG. Monitoring the level of the main hormone of pregnancy will help maintain the condition of the woman in pregnancy and the fetus in a normal state.

HCG during pregnancy: the norm is not met

There are situations in which the above standards are not observed, which indicates the presence of pathology in the body of a pregnant woman or fetus. Decreased or elevated levels of this hormone will be of diagnostic importance.

Reasons for increasing hCG

Multiple pregnancy (twins, triplets, etc.). In such a situation, the level of concentration of the hCG hormone will increase in proportion to the number of children.
Diabetes mellitus in a pregnant woman.
Taking progestin medications.
Toxicosis or gestosis in a pregnant woman.
Pathology of the fetus of a chromosomal nature.
Incorrectly set gestational age.

Reasons why hCG levels decrease

Incorrectly set gestational age.
Threat of miscarriage (hCG is reduced by more than 50% of normal).
Ectopic pregnancy.
Delayed normal fetal development.
Chronic placental insufficiency.
A pregnancy that does not develop.
Intrauterine fetal death.
Post-term pregnancy of a true nature.

Even non-pregnant women and men may have diseases in which elevated levels of human chorionic gonadotropin will be detected. These include: tumors of the kidneys, uterus, testicles, digestive tract, chorionic carcinoma (cancer) and hydatidiform mole.

Interpretation of the obtained analysis for hCG

After receiving the form with the result of the analysis, the woman should come to see her doctor, since only a qualified specialist can accurately and confidently assess the obtained hCG numbers. HCG indicators must be assessed only according to the reference values of the laboratory in which the venous blood analysis was studied. Each laboratory has its own hCG standards for weeks of gestation. For correct interpretation, the gynecologist uses a table where the approximate hCG norms for weeks of pregnancy are recorded, and he also focuses on the state of the pregnancy and the anamnestic data of the women.

HCG values by week of pregnancy are recorded in table form and measured in mIU/ml:

In non-pregnant women, hCG levels range from 0 to 5;
The result is considered questionable if the hCG level is from 5 to 18 and requires a retake after 48-72 hours;
3-4 weeks – 1500-4500;
4-5 weeks – 18000-900000;
5-6 weeks – 40,000-220,000;
6-7 weeks – 43000-230000;
7-8 weeks – 23000-220000;
8-9 weeks – 19000-120000;
9-10 weeks – 21000-94000;
11-12 weeks – 22000-89000;
13-14 weeks – 19000-56000;
15-25 weeks – 13000-32000;
26 - 37 weeks - 12000-60000.

The level of hCG by week of gestation is a very important diagnostic criterion, on the basis of which a conclusion is made about the condition of the embryo, and it is also a marker of various chromosomal developmental abnormalities in the fetus and congenital pathology of internal organs in the child. When assessing hCG results by week of pregnancy, differences that exceed 25% of the reference values are taken into account. An increase or decrease in hCG levels by 50% or more is considered to be a pregnancy pathology.

HCG as a marker of fetal abnormalities

Every pregnant woman at a certain stage of pregnancy must undergo a series of screening examinations, which will allow us to suspect the presence of a possible problem as early as possible. Determination of the level of human chorionic gonadotropin is included in this list.

Anomalies of fetal development in which the level of hCG increases:

Down syndrome, Patau syndrome, Edwards syndrome, Turner syndrome and severe structural disorders of the fetal neural tube.

In cases where, based on the results of screening examinations, an abnormality of fetal development was suspected, the pregnant woman is prescribed a number of additional tests and examinations. Depending on the stage of pregnancy, different techniques are used: cordocentesis, amniocentesis or fetal chorionic villus biopsy. In addition, consultation with a geneticist is required.

Functions of gonadotropin

HCG produced during pregnancy performs the following functions:

stimulation of the formation of estrogen and progesterone;
corpus luteum support;
supporting maternal immunity.

HCG tests in early pregnancy reveal a sharp increase in the hormone. At this time, the fetus is not yet able to produce the necessary hormones, and it requires hormonal support. When the fetus begins to form a sufficient hormonal background, the hCG level will begin to subside. In addition to hCG during pregnancy, it is necessary to take tests for other hormones.

HCG for ectopic pregnancy

An ectopic pregnancy is a pregnancy in which the embryo attaches anywhere other than the inner wall of the uterus. This can be the right or left fallopian tube, the abdominal cavity, the ovaries and other places along the path of the egg during ovulation. An ectopic pregnancy is a very dangerous condition, because in addition to the fact that it is almost always interrupted, it can cause enormous harm to the female body, even death.

Determination of hCG during pregnancy (the norm is given above) in combination with an ultrasound examination of the pelvic and abdominal organs is the “gold standard” in diagnosing ectopic pregnancy and determining the site of embryo attachment. In the presence of an ectopic pregnancy, a much lower level of human chorionic gonadotropin is determined in the blood than should be normal. This is due to the fact that the outer shell of the fruit produces much less of it. With increasing gestational age, there is no significant increase in hCG.

In situations where a low level of hCG indicates an ectopic pregnancy, and ultrasound diagnostics does not reveal the exact site of attachment of the embryo, laparoscopic surgery is prescribed.

To the symptoms of ectopic pregnancy

include: bloody vaginal discharge, abdominal pain that began after a missed period, fainting conditions combined with a delayed period. Determining hCG during pregnancy (the norm at the beginning of the article by week) with such symptoms will help determine the problem.

Analysis process

For more information about the blood test for hCG, read this material - note. altravita-ivf.ru.

Table of hCG values by day during pregnancy

Women after IVF are recommended to take hCG every two to three days; clinics use a daily table. The table displays: day of transfer, average, minimum and maximum hormone values. The table is extremely easy to use. To evaluate the results obtained, you need to select the “age” of the embryos, determine the day after the transfer and compare the results of laboratory research with the data in the table.

The day after the egg leaves the follicle	Range and average hCG numbers	Pregnancy Day	Interval from minimum to maximum
7	2-10 (4)	25	2400-9800 (6150)
8	3-18 (7)	26	4200-15600 (8160)
9	5-21 (11)	27	5400-19500 (10200)
10	8-26 (18)	28	7100-27300 (11300)
11	11-45 (28)	29	8800-33000 (13600)
12	17-65 (45)	30	10500-40000 (16500)
13	22-105 (73)	31	11500-60000 (19500)
14	29-170 (105)	32	12800-63000 (22600)
15	39-270 (160)	33	14000-68000 (24000)
16	68-400 (260)	34	15500-70000 (27200)
17	120-580 (410)	35	17000-74000 (31000)
18	220-840 (650)	36	19000-78000 (36000)
19	370-1300 (980)	37	20500-83000 (39500)
20	520-2000 (1380)	38	22000-87000 (45000)
21	750-3100 (1960)	39	23000-93000 (51000)
22	1050-4900 (2680)	40	25000-108000 (58000)
23	1400-6200 (3550)	41	26500-117000 (62000)
24	1830-7800 (6550)	42	28000-128000 (65000)

Having received the test results, there is no need to worry if the hCG is outside the normal range in any direction. For each woman, the concentration is individual and differs at different times. Sometimes the difference can be up to 1000 IU/l and is considered normal for one pregnant woman, a risk criterion for another, and a pathology for a third. Therefore, only a doctor interprets the tests.

HCG during frozen pregnancy

A situation where, for any reason, the fetus stops developing and dies, but spontaneous miscarriage does not occur, is called a frozen pregnancy (antenatal fetal death). This condition can be suspected based on the following signs: delayed menstruation, a positive pregnancy test, the absence of external signs of a developing pregnancy, a stop in the rate of increase in hCG and then its gradual decrease, the absence of a fetal heartbeat on ultrasound or other obvious signs.

Reasons why the fetus freezes:

abnormalities of the chromosomal apparatus incompatible with life, inflammation of the endometrium of the uterus, pathology of the structure of the uterus and many others.

Then, when a miscarriage during a frozen pregnancy does not occur on its own, an abortion is performed by medication (administration of special medications) or by curettage of the uterine cavity.

HCG and specific tumors

Such processes include complete or partial hydatidiform mole (pathology of the fetal egg) and chorionic carcinoma.

Hydatidiform mole is not a true malignant neoplasm, but can lead to disastrous consequences. That is why it is necessary to diagnose it as early as possible. The level of hCG during pregnancy (see the norm above) in a woman with a hydatidiform mole is several times higher than normal levels. If the diagnosis is not made in a timely manner and the chorion is removed, it can develop into a malignant tumor - chorionic carcinoma, and quickly metastasize to various organs.

Preparing to donate blood for hCG

If a pathology is suspected, the doctor may additionally prescribe a blood test for hCG during pregnancy. Whether it’s normal or pathological is not always easy to figure out, because there may be various factors that distort the result of the analysis. It is for this purpose that a number of recommendations have been developed,

which should be followed on the eve of blood sampling:

Avoid excessive physical activity at least 24 hours before donating blood.
You cannot take medications.
Avoid drinking alcohol.
Smoking is prohibited 3 hours before the test.
It is not recommended to donate blood for hCG after various additional examinations and physiotherapeutic procedures (X-rays, ultrasound, massage, etc.).
It is advisable for a woman to come to the blood donation procedure well rested and without stress.
The most suitable time for blood collection is considered to be the morning (from 8 to 10 o'clock).
Blood is drawn on an empty stomach. You can't do anything other than a glass of still water.
It should be noted that when repeating blood tests for hCG, it is not recommended to change the conditions under which the first test was taken. Following this simple rule will help make a correct comparison over time.

When to take hCG

Testing human chorionic gonadotropin concentrations is a complex test. For the results to be reliable, established rules must be followed.

Blood is drawn from a vein on an empty stomach. Twenty-four hours before the study, the patient is advised to exclude fried foods, fatty foods, and alcoholic beverages are prohibited. If at the time of donating blood the patient is being treated with hormonal medications, she must inform the doctor. HCG levels are monitored over time. It is advisable to perform the study in one laboratory at a certain time of day.

HCG analysis is the optimal indicator of proper pregnancy.