HCG (human chorionic gonadotropin) is a hormone released during pregnancy. Using a laboratory blood test, the concentration of beta subunits is determined. Conception can be detected using this method as early as 6-8 days. The hCG test also differentiates a normal pregnancy from an ectopic one. The online hCG calculator will help you decipher the blood test. You will be able to track the dynamics of hormone growth indicators and be able to determine the duration of pregnancy.
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What is hCG - “beta”?
The content of the article
HCG is a hormone that is produced by the fetus itself, or rather by the fetal membrane of the embryo (chorion). The process begins immediately when the embryo is implanted into the uterus. At this moment, the fetus still looks like a small bubble of liquid, consisting of an embryoblast (from which the fetus will form in the future) and trophoblast (cells that form the chorion).
Under the influence of gonadotropin, the corpus luteum produces hormones that maintain the condition of the endometrium (the inner lining of the uterus) necessary for normal pregnancy. An increase in hCG concentration indicates that fertilization has taken place.
HCG contains:
- Alpha subunits. They are not determined because they have no diagnostic value during pregnancy.
- Beta subunits, which make it possible to determine the fact of conception and the period of fetal development.
That is why the term human chorionic gonadotropin in pregnancy tests refers to its beta component.
Biological properties
In terms of biological functions, hCG is similar to luteinizing and follicle-stimulating hormones. It binds to both types of gonadotropic receptors, but is significantly superior to gonadotropins in biological activity. Thanks to hCG, the corpus luteum functions for up to 12 weeks, instead of the usual two. After 12 weeks, the placenta forms, producing estrogen and progesterone. In addition, hCG stimulates the production of female sex hormones and weak male hormones in the ovarian follicles.
There is evidence that human chorionic gonadotropin activates the synthesis of steroids by the adrenal cortex. This can help the body adapt to pregnancy as stress, suppress the function of the immune system and prevent fetal rejection. The data are confirmed by the fact that corticotropic hormones produced in the pituitary gland do not have such properties.
Another function of human chorionic gonadotropin is to maintain placental function. The hormone improves the nutrition of the organ and increases the number of chorionic villi. An injection of the hormone in the middle of the cycle increases the production of estrogens and progesterones, promotes ovulation and the formation of the corpus luteum. In men, a synthetic hormone stimulates the production of sperm and androgens. An increase in hCG in the absence of pregnancy indicates a malignant disease.
How do hCG levels change during pregnancy?
For the first time, an increase in beta-hCG levels is detected starting from the sixth day after conception. At first, the concentration of the hormone doubles every two days. Further, the increase in hCG concentration slows down and when the level reaches 1200 mU/ml, doubling begins to occur every 72-96 hours. Upon reaching 6000 mU/ml, growth occurs every 96 hours.
The concentration indicator is not just boring numbers: it is what helps determine the gestational age.
After 11 weeks, the hormone in the body becomes less, but its level is still increased. At 34 weeks, a second increase in hCG occurs. This surge, according to scientists, triggers labor. After childbirth, the level of beta-hCG in the blood gradually decreases.
Treatment tactics
Based on the results of the study, the doctor develops further treatment tactics.
Pregnancy support is canceled in the following cases:
- human chorionic hormone level is negative;
- the level of chorionic hormone is reduced; ultrasound examination does not detect the fertilized egg.
Further administration of synthetic hormones in such cases will negatively affect the menstrual cycle, while the woman could be preparing for the next protocol. If the indicators are normal, and a developing fertilized egg is visualized on ultrasound, pregnancy is supported, and studies are repeated regularly, according to the drawn up scheme. If the level of human chorionic gonadotropin is elevated, the woman should be further examined. An ultrasound examination, laboratory tests, and genetic consultation are prescribed. The decision to carry such a pregnancy is made strictly individually, based on the results of examinations.
Online hCG calculator
The calculator will help you when deciphering blood tests for hCG. You will be able to monitor the growth dynamics of Beta-hCG and determine the duration of pregnancy.
The results indicated in the tables and the hCG calculator itself are approximate. To determine this hormone, various methods can be used and indicators may vary. Therefore, the analysis is deciphered where it was done. The units of measurement for the concentration of beta-hCG are also different. The concentration is indicated in honey/ml, mIU/ml, U/l and IU/l as well as U/l mIU/ml, IU/l. All indicators are the same and do not need to be recalculated. U stands for units, IU stands for international units, mIU/ml and U/l are the English display of units.
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.
Beta-hCG levels at different stages of pregnancy
| Days after last menstruation | Gestation period (days/weeks) | HCG in honey/ml |
| 26 | 12 | 0-50 |
| 27 | 13 | 25-100 |
| 28 | 14 (2 weeks) | 50-100 |
| 29 | 15 | 100-200 |
| 30 | 16 | 200-400 |
| 31 | 17 | 400-1000 |
| 32 | 18 | 1050-3000 |
| 33 | 19 | 1450-4000 |
| 34 | 20 | 1940-5000 |
| 35 | 21 (3 weeks) | 2600-6500 |
| 36 | 22 | 3400-8500 |
| 37 | 23 | 4400-10800 |
| 38 | 24 | 5700-13700 |
| 39 | 25 | 7200-17000 |
| 40 | 26 | 9000-21000 |
| 41 | 27 | 10100-23300 |
| 42 | 28 (4 weeks) | 11200-2550 |
| 43 | 29 | 13700-30900 |
| 44 | 30 | 16600-36500 |
| 45 | 31 | 19900-43000 |
| 46 | 32 | 25500-50200 |
| 47 | 33 | 27450-57650 |
| 48 | 34 | 31700-65400 |
| 49 | 35 (5 weeks) | 36100-73200 |
| 50 | 36 | 40700-81150 |
| 51 | 37 | 45300-88800 |
| 52 | 38 | 49800-96000 |
| 53 | 39 | 54100-102500 |
| 54 | 40 | 58200-108200 |
| 55 | 41 | 61640-112800 |
| 56 | 42 (6 weeks) | 64000-116310 |
Concentration of chorionic gonadotropin at later stages
| Duration in weeks | HCG concentration honey/ml |
| 7 | 65000 – 155000 |
| 8 | 67500 – 190000 |
| 9-10 | 70000 – 211000 |
| 11-12 | 13500 – 63000 |
| 13-14 | 1200 – 71000 |
| 15-25 | 8000 – 60000 |
| 26-37 | 5000 – 55000 |
Why is a beta-hCG blood test more sensitive than a drugstore test?
Pregnancy tests are not accurate for the following reasons:
- The concentration of hCG in urine is almost two times lower than in the blood, so even the most sensitive test will give a false negative result in the early stages.
- Human chorionic gonadotropin tests sold in pharmacies are capricious and may not work correctly. Reasons: inaccurate analysis, expired reagent, improper storage of the test.
- If you drink a lot of water in the evening or take a diuretic, the test will not detect pregnancy. Tests also give false negative results for kidney diseases.
Every year there are thousands of mothers in the world who for a long time did not imagine their “interesting situation”, trusting pharmacy strips.
Blood test for early pregnancy - why it is needed and how to donate blood correctly - MEDSI
Table of contents
- Reasons for conducting the study
- HCG changes during pregnancy
- Reasons for deviations from the norm of the hCG hormone
- Reasons for increasing hCG levels
- Preparation for the procedure
- How is blood sampling performed?
- Advantages of carrying out the procedure at MEDSI
A blood test for pregnancy is a procedure that is necessary to identify existing pathologies.
It also allows you to determine the presence of pregnancy itself, since it detects the presence in a woman’s blood of a hormone called human chorionic gonadotropin (hCG). In a situation where conception has not occurred, this substance is not produced in the patient’s body, since its appearance is associated with the formation of chorion. This is the tissue that appears between the endometrium and the zygote after a fertilized egg attaches to the wall of the uterus.
Reasons for conducting the study
A blood test can show the presence of pregnancy as early as the sixth day after successful conception. Whereas a standard pregnancy test in some cases can give incorrect results. Therefore, tests during pregnancy are prescribed to determine conditions such as:
- Establishing the actual fact of conception
- Assessment of hormonal levels for disruptions
- Tracking pathological types of pregnancy:
- Frozen - in this case, at a certain stage the embryo stops its development
- Ectopic - in this situation, the zygote is not attached to the wall of the uterus, but in the fallopian tube
A blood test also shows the presence of infections, other types of dysfunction of the body and diseases such as:
- Cytomegalovirus
- Diphtheria
- Tetanus
- Herpes
- Chlamydia
- Hepatitis
- Ureaplasmosis
- HIV
- Mycoplasmosis
- Syphilis
- Leptospirosis
- Chlamydia
Any of these diseases poses a danger not only to the woman’s body, but also to her unborn child. Therefore, if there are abnormalities in the blood test results, the doctor refers the patient for additional examination.
HCG changes during pregnancy
After the physical onset of conception, the level of hCG in the female body begins to rise, and every two to three days its concentration almost doubles. It reaches its highest level at 8–11 weeks, and then it begins to gradually decrease.
The first test can be taken on the 6th day of the expected delay, but the result will be more accurate on the 11th–12th day. Therefore, doctors recommend undergoing blood tests two to three times (every two days each).
Monitoring the level of hCG allows you to monitor the dynamics of pregnancy development, the appearance of pathologies, etc.:
- During an ectopic pregnancy, the hormone level practically does not increase
- If the development of the embryo has stopped, then the level of hCG drops from the moment of its death
Usually the analysis result is compared with a special table. In the first or second weeks, the concentration of hCG can range from 25 to 700 units, at its peak it can reach 18,000–240,000 units, and at the end of pregnancy – 2,179–60,000 units.
After establishing the fact of conception, the doctor refers the patient to other blood tests:
- General
- Biochemical
- For clotting
- For hepatitis and HIV
- For the presence of TORCH infections
- For genetic pathologies
- For Rh factor and blood group (if they have not been determined previously)
- The content of hormones produced by the thyroid gland
- For antiphospholipid syndrome
- For STDs
Reasons for deviations from the norm of the hCG hormone
Normally, after pregnancy, the level of human chorionic gonadotropin should gradually increase. If it decreases, the doctor may suggest the presence of problems such as:
- In the early stages:
- Fetal death
- The likelihood of spontaneous abortion
- Absence of embryo in fertilized egg
- Placental abruption
In some cases, low hCG levels may be associated with incorrectly calculated gestational age. Therefore, to determine the exact cause of low hormone levels, early pregnancy tests are usually performed, as well as several types of other tests.
Reasons for increasing hCG levels
In the results of blood tests, the level of hCG may be seriously higher than normal for the following reasons:
- Presence of toxicosis
- Formation of more than one fetus
- The appearance of a hydatidiform mole
- Presence of genetic problems
- Complication due to diabetes mellitus
The level of human chorionic gonadotropin can be increased not only due to pregnancy, but also due to certain abnormalities:
- Extremely high hCG levels due to hormonal medications
- The presence of a malignant neoplasm in various organs (kidneys, gastrointestinal tract, uterus, lungs, etc.)
- Preservation of unstable hormonal levels as a result of an abortion
In rare cases, in the presence of serious hormonal imbalances, elevated levels of hCG may also be found in men.
Preparation for the procedure
Before taking tests for pregnant women for the amount of hCG, the following preparation is required:
- Fasting for 7–8 hours before the procedure
- Limiting any liquid intake several hours before the examination
It is also necessary to warn your doctor about taking medications.
Statistics show that the highest concentration of hCG in the blood is observed in the first half of the day, so the doctor usually prescribes such a test in the morning.
If the recommendations are not followed, the study may show an unreliable result, so additional procedures will have to be performed.
How is blood sampling performed?
Blood tests for pregnant women are taken from a vein in the area located on the inside of the arm at the elbow. The procedure goes as follows:
- The patient sits on a couch or chair and exposes her left or right arm
- A medic applies a tourniquet above the elbow
- After this, the woman clenches her palm into a fist several times
- The doctor lubricates the area of the future puncture with a disinfectant
- Then he inserts a needle into the vein and fills the syringe (about 10 ml of blood is needed for the study)
- After this, the tourniquet is removed, and a cotton swab is applied to the puncture area, which the patient must press with her hand bent at the elbow (this helps stop the release of fluid from the wound)
After these manipulations, the blood in a test tube is sent to the laboratory for testing. The results of the analysis can be transferred directly to the attending physician or given to the patient. A woman can independently compare the indicated indicators with the values in the tables, but it is recommended to entrust this process to professionals.
Advantages of carrying out the procedure at MEDSI
- The clinics employ highly qualified doctors who not only develop comprehensive examination and treatment programs, but also help to properly prepare for childbirth if pregnancy occurs
- Special consultation mechanisms have been created for future parents
- The clinics have their own laboratory for receiving and checking tests, which allows you to get accurate results in the shortest possible time
- For examinations and therapy, modern devices from leading manufacturers from countries such as Japan, USA, Germany, etc. are used.
- Original drugs are used (not generics)
To make an appointment, you must call 8 (495) 7-800-500 or contact one of the many registries located in Moscow, the region and regions of the Russian Federation.
Do not delay treatment, consult a doctor now:
- Analysis during pregnancy
- Gynecologist appointment
- Planning and management of pregnancy
- Reproductive health
How is a human chorionic gonadotropin test taken?
For the analysis, blood from a vein is needed in the morning on an empty stomach. Measurement of beta-hCG concentration is performed no earlier than 3-5 days after a missed period. When taking hormones, you need to inform your doctor about this - they can affect the concentration of hCG.
To diagnose congenital pathologies (perinatal screening), an hCG test is performed at 14-18 weeks. Determination of hCG in men and non-pregnant women (analysis for tumor markers) can be carried out on any day.
HCG norms
As mentioned earlier, chorionic hormone begins to grow rapidly from the first days of pregnancy. The dynamics of its increase trace the course of pregnancy. If its level begins to drop sharply, this may indicate the development of an ectopic pregnancy, the appearance of a threat of miscarriage, placental insufficiency or missed abortion. It is especially important to monitor hCG levels over time if there is a history of miscarriages. The frequency of testing should be determined by the attending physician.
To obtain reliable data on changes in hormone levels, the study must be carried out in the same laboratory. This is due to the fact that different laboratories use different equipment and reagents to perform tests, and may also present results in different units of measurement. You can choose a laboratory yourself, based on your own experience or on the recommendation of your attending physician.
Below are the approximate norms for hCG levels by week of pregnancy (the norms established in the laboratory will be indicated on the results sheet):
- 1-2 weeks: 25-160 mIU/ml;
- 3-4 weeks: 1120-31400 mIU/ml;
- 5-6 weeks: 23200-51100 mIU/ml;
- 7-11 weeks: 20800-291100 mIU/ml;
- 11-16 weeks: 6130-103100 mIU/ml;
- 16-21 weeks: 4620-80200 mIU/ml;
- 21-39 weeks: 2800-78000 mIU/ml.
The concentration of beta-hCG is different from the norm, what does this mean?
The online hCG calculator only works to determine pregnancy. If pregnancy is not confirmed and there are no other signs of pregnancy, you need to make an appointment with an oncologist. An increase in the hCG hormone can occur in both non-pregnant women and men. This indicates malignant tumors of the uterus (chorionepithelioma, chorionic carcinoma) or testicles. An increase in the hormone is also observed in cancer of the bladder, kidneys, intestines, and lungs.
| Excess hCG | Decreased hCG |
| Multiple pregnancy. In case of twins or triplets, the level is proportional to the number of embryos | Risk of miscarriage |
| Toxicosis | Death of an embryo or fetus |
| Down syndrome (more research needed) | Frozen pregnancy |
| The term is incorrectly defined | Placental insufficiency |
| Post-term pregnancy | |
| Ectopic pregnancy | |
| Hydatidiform mole | |
| Pregnancy after stimulation or IVF |
If a high level of hCG persists after an abortion, this indicates an incomplete abortion - incomplete removal of the fertilized egg or an ongoing pregnancy. Gonadotropin levels also increase when taking hormonal medications.
Deviations
Sometimes pregnancy may not develop, but a hydatidiform mole occurs - the growth of chorionic villi in the form of bubbles with liquid contents. At the same time, human chorionic gonadotropin also increases, which can be mistaken for the presence of pregnancy. In this case, the patient must undergo ultrasonography and other studies to make an adequate diagnosis and eliminate the drift, since it can transform into a malignant tumor if treatment is not carried out in time.
HCG variability can mean different conditions when indicated:
| Understated | Overpriced |
| Ectopic pregnancy | Incorrect determination of gestational age |
| Incorrect deadline | Multiple pregnancy - twins, triplets, especially fraternal ones. Heterozygous twins have their own placenta, each of which intensely secretes the hormone |
| The fetus is delayed in development | Chromosomal mutations (high probability of Edwards Syndrome). If the hormone increases in the second trimester, then Down syndrome is possible |
| Risk of miscarriage | Diabetes mellitus in an expectant mother |
| Placental insufficiency | Preeclampsia |
| Non-developing pregnancy | Taking synthetic progesterone |
| Post-maturity | Early toxicosis |
| Intrauterine death of a child | |
| After in vitro fertilization, conception did not occur or the embryo did not implant |
Where to get tested for hCG in St. Petersburg
You can get tested without queues and quickly get accurate results at the Diana Clinic in St. Petersburg. When deciphering, specialists take into account all factors that can affect the level of beta-hCG, which eliminates errors. Here you can consult with experienced gynecologists who will explain what to do in a given situation.
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HCG as part of pregnancy screening
The level of the hormone is determined in venous blood serum. No complex preparation is required for diagnosis. Biomaterial is collected in the morning.
General preparation rules:
- diagnostics are carried out on an empty stomach;
- the woman must inform the gynecologist about all medications used, because the drugs can affect the results of laboratory diagnostics;
- on the eve of donating blood, it is necessary to limit physical activity and eliminate the effect of unfavorable factors;
- other instrumental studies are carried out after diagnosis and determination of the level of pregnancy hormone in the blood.
After collection, the blood is placed in a centrifuge and then separated into fibrinogen and serum. Specialists then determine beta units using immunometric methods. The woman is informed of the result within 24 hours. The hCG level increases in proportion to the number of fetuses.
