HCG analysis - when is it prescribed and what does it show?

Human chorionic gonadotropin, or hCG, is a protein produced by the membranes of a developing embryo. It is responsible for the course of pregnancy, blocking menstruation, and helps increase the concentration of hormones that are needed to preserve the fetus. The presence of hCG in a woman’s blood is one of the early signs of conception. It must be said that the human pituitary gland produces a small amount of hCG, so in some cases a small concentration of it can be found in the blood of men and women (including those in menopause).

HCG: role in the body

The main function of hCG is a signal that a woman’s body needs to be rebuilt in connection with the onset of pregnancy. It affects sex hormones, activates increased production of estradiol, progesterone and estriol, which change the hormonal background of the expectant mother. By monitoring the activity of hCG, you can assess how the fetus is developing and what the likelihood of miscarriage is.

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Starting from week 7, gonadotropin is responsible for the development of the corpus luteum, maintaining its functionality. There is an assumption that it suppresses the mother's immune system, due to which the fetus is not rejected.

Reference! The pregnancy test strip is based on a method for assessing the level of human chorionic gonadotropin in the blood. But in this case, the material being studied is urine, and in it the concentration of the hormone increases more slowly. Therefore, if a blood test can detect pregnancy on the second day after fertilization, the test can do this only after 7 days.

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.

Types of hCG tests

The following types of tests for human chorionic gonadotropin are distinguished:

1. General - prescribed for diagnosing conception (on the 2nd day after fertilization, when the test strip cannot yet show the correct result). If there are no pathologies and the pregnancy proceeds normally, in the first weeks the hCG level doubles every two days, and reaches its maximum values ​​by 10–11 weeks of gestation. After this, its level decreases. In multiple pregnancies, the hCG level increases in accordance with the number of fetuses.
2. Free β-hCG - analysis shows the presence of testicular and trophoblastic neoplasms. It is also used in screening studies in the 2nd and 3rd trimester to exclude Edwards and Down syndrome. If a positive result is observed, the woman is transferred to the risk group, but this cannot be a 100% guarantee of the occurrence of chromosomal mutations in the fetus. The age of the pregnant woman over 35 years, a family history of Down's disease, the presence of genetic defects in close relatives, and radiation exposure are indications for a more thorough study of hCG. In all other cases, this test is prescribed at 8–13 and 15–20 weeks of pregnancy.

Accuracy check / My baby and I

Consultant: Nona Hovsepyan, consultant physician, Independent Laboratory INVITRO Text: Natalia Rubina

We, of course, understand that in a magazine like ours it’s already a little late to write about pregnancy tests. But very often visitors to the site krokha.ru have questions: “How can I tell if I’m pregnant? Can the test be wrong?

How it works?

All pregnancy tests operate on the same principle - they recognize a special hormone called human chorionic gonadotropin (hCG) in urine (tests for home use) or blood (laboratory tests). It is produced only during pregnancy. A non-pregnant woman simply cannot have it (more precisely, it can, but only in exceptional cases, which are discussed below). The amount of hCG in the body from the moment the fertilized egg attaches to the wall of the uterus doubles approximately every 2-3 days and reaches a maximum by 7 - 12 weeks of pregnancy. Its presence in the blood and urine can be detected until approximately the third week after birth.

When purchasing a pregnancy test, pay attention to its sensitivity. Typically, most tests have a sensitivity of 20-25 mIU/mL (international units per mL). They are able to recognize pregnancy only from the first day of missed menstruation. Whereas there are more sensitive (but also more expensive) tests (10 mIU/ml) that can determine pregnancy within 7-10 days from the moment of expected conception. And after a week of delay, pregnancy (if any) will be shown by any tests.

If you want to find out if you are pregnant as early and accurately as possible, it is better to go and have a blood test done at a antenatal clinic or a specialized laboratory. HCG appears in the blood faster than in the urine, so pregnancy can be determined even before the expected period (but not earlier than 7 days from the date of conception). A blood test can be qualitative (the answer will be: yes or no) and quantitative, when the analysis form will tell you the exact amount of hCG in your blood. It is better to do the second option, since then (by taking it several more times) it will be possible to monitor the dynamics of the development of pregnancy. Doing a dynamic test, in particular, is useful to recognize a pregnancy that has frozen in the early stages. If the embryo freezes in development, the hCG level stops growing, and the test will immediately show this. QUESTION ON THE SITE WWW.KROKHA.RU

Olga B. “On the second day of the delay, I took a test, and it showed two lines. But one of them is very weak. Am I pregnant? Nona Hovsepyan: Even if the second line is weak, but there, you are pregnant. However, if in doubt, re-test 3-4 days later. The level of hCG in the body will increase noticeably and the stripe will be much brighter. Can a test lie? All instructions say that pregnancy tests are 95-99% accurate. This means that there is a chance that the result will be incorrect. So, a false negative result is possible if:

• you performed the test too early and the level of hCG in the urine is still too low; ^ the test has expired (so carefully study the packaging before buying the test); • you performed the test incorrectly (although it is difficult to imagine that this is possible - everything is extremely simple there); • drinking too much liquid the day before the test can dilute the urine and reduce the concentration of hCG;

The test can also show a false positive result:

• if you are taking fertility drugs that contain hCG (usually in the form of injections); • HCG can appear in the body during hydatidiform mole, a disease associated with the pathology of the trophoblast (a temporary organ necessary for attachment of the embryo to the wall of the uterus). During hydatidiform mole, the trophoblast degenerates into a huge number of small bubbles. These bubbles occupy the entire uterine cavity and tend to grow rapidly. The main symptom of hydatidiform mole is bloody vaginal discharge due to delayed menstruation. To clarify the diagnosis, you need to see an obstetrician-gynecologist as soon as possible; • Normally, elevated hCG levels can be observed up to 3 weeks after premature birth or miscarriage. But a positive test result may also mean that remnants of the fertilized egg remain in the uterus. In order to find out, you need to do an ultrasound and, if necessary, curettage of the uterine cavity.

Cannot influence the result:

• kidney diseases; • taking contraceptive medications; • taking antibiotics; • drinking alcohol; • lactation.

What tests are there?

1. Strip tests (paper strips).

These are the simplest, cheapest and most common tests. The strip needs to be lowered for 10-20 seconds to a certain mark in a container with morning urine (it is the most concentrated). After this, place the test on a horizontal surface and evaluate the result after a few minutes. One line means you are not pregnant, two lines means you are pregnant.

2. Tablet tests.

They are designed in the same way as strip tests. Only the paper strip is placed in a plastic case. And the previously collected morning urine needs to be dropped into a special hole with the pipette included with the test. The result is also shown in the form of one or two stripes.

3. Jet tests.

Their convenience is that there is no need to collect urine anywhere—the test strip just needs to be placed under the stream. In this case, urine does not have to be morning. Inkjet tests are more sensitive. The result is assessed by one or two stripes.

4. Electronic tests.

They have a special strip - a sample receiver, which you can optionally lower into a container with urine or place under the stream. The result is read in 3 minutes. If “+” or the inscription “pregnant” appears on the test, you are pregnant, but if “-” or “not pregnant”, you are not.

5. Interactive tests.

Recently, a lot of so-called virtual or interactive tests have proliferated on the Internet. But there is not the slightest sense in believing them. At best, this is just a scam, at worst, it’s a way for scammers to make money. So, in the simplest tests, you are asked to place your finger on a square on the screen, and if after 2 minutes it turns red, you are pregnant, but if the square turns blue, you are not. The square turns red even if you don't touch the screen. Apparently this test is for those who have no doubt that they will soon become a mother. More complex tests ask you to answer a number of questions, including “Have you recently had unprotected sex?” and “Do you feel engorgement in your breasts?” As a result, it is proposed to receive a response after sending an SMS to a specific number.

Can a test detect an ectopic pregnancy?

If the fertilized egg has implanted outside the uterus, a regular pregnancy test will still be positive. However, such a pregnancy, as a rule, is terminated at 7-8 weeks, and this is accompanied by large blood loss and serious problems for the woman’s health. To avoid this, it is better to recognize and terminate an ectopic pregnancy in advance (it is impossible to save it).

The main symptoms of an ectopic pregnancy: with a positive pregnancy test, nagging pain in the lower abdomen and spotting appear. In this case, you need to get an ultrasound as soon as possible. With an ectopic pregnancy, there is no fertilized egg in the uterine cavity, but the doctor will notice the growth of the endometrium, as in a normal pregnancy.

If you belong to a risk group (adhesions, inflammation of the appendages, or have previously had an ectopic pregnancy), then it is better to conduct a high-quality pregnancy test using blood over time. During an ectopic pregnancy, the level of hCG in the blood is lower than during a normal pregnancy, and the test will immediately show this.

IT IS IMPORTANT!

Despite the fact that all women have different lengths of the menstrual cycle, the period after ovulation for all is 14 days, which means that by the beginning of the next cycle, pregnancy can already be determined, since implantation of the fertilized egg occurs approximately 6-7 days after conception.

FOLK WISDOM

When there were no pregnancy tests yet, our ancestors knew other ways to diagnose pregnancy.

Collect some urine in a jar and drop a drop of iodine into it. If the drop dissolves in urine, this indicates the absence of pregnancy. If the drop holds a large shape, the woman is pregnant.

In Ancient Greece, it was believed that a pregnant woman's iris became slightly darker.

Water the flowers in the flower bed with morning urine. If the flowers bloom very profusely after this, it means the woman is pregnant.

Take two onions and plant them in two pots. Write “yes” on one and “no” on the other. Water both bulbs with morning urine and wait until one of the sprouts sprouts. If the bow with the inscription “yes” is the first to “throw out an arrow,” this means that pregnancy has occurred.

HCG during pregnancy

Reference! The data presented are averages; in addition, each laboratory has its own unit of measurement of hormone levels and its own rating scale.

Reduced concentration of hCG during pregnancy:

1. If the indicators decrease by 50% or more relative to the norm, we can talk about an existing threat.
2. Fetal development problems.
3. Chromosomal abnormalities in the fetus, such as Edwards syndrome.
4. With a sharp decrease in indicators in the second and third trimester, a frozen pregnancy or fetal death is possible. In this case, at the beginning, hCG is normal, and then stops increasing or decreases sharply.
5. Ectopic pregnancy.
6. Diabetes.
7. If the concentration of the hormone decreases in the later stages, post-term pregnancy is possible.

If the analysis result shows a low level, do not immediately panic and draw conclusions. The gynecologist could have made a mistake with the date of expected conception, which happens quite often when a woman gives inaccurate information about her cycle, on the basis of which the day of ovulation is calculated.

Increased concentration:

1. Early toxicosis.
2. Postmaturity of the fetus.
3. Incorrect deadline.
4. Chromosomal abnormalities - if hCG rises sharply in the 2nd trimester, the fetus may develop Down syndrome.
5. Multiple pregnancy - in this case, the level of hCG in the first weeks of pregnancy may exceed the norm by 2-3 times. This is due to the fact that the hormone is produced by several membranes at once.

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.

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.

Analysis for hCG in non-pregnant women

The level of human chorionic gonadotropin can increase in the body of non-pregnant women with the development of the following pathologies or physiological conditions:

1. Tumors in internal organs.
2. Neoplasms or other pathologies of the ovaries.
3. Tumors of the uterus.
4. Hydatidiform mole is a pathological pregnancy.
5. A tumor that occurs when the chorionic epithelium becomes malignant.
6. Miscarriage or abortion less than a week ago.
7. Use of hormonal medications that contain gonadotropin. As a rule, they are prescribed at the preparatory stage before IVF.
8. Childbirth - After childbirth, gonadotropin levels remain elevated for approximately 7 days. After which it gradually decreases and reaches 5 mU/ml.
9. Menopause - after the final cessation of menstrual bleeding, hCG can increase to 14 mU/ml, which is a normal value for a woman during this period.

Concentration of chorionic gonadotropin at later stages

hCG in men

Normally, in men, human chorionic gonadotropin should be 0–5 units. This indicator indicates the patient's satisfactory condition. If it is elevated, this indicates a disruption in the functioning of internal systems and organs:

• malignant process in the testicles;
• oncology of the gastrointestinal tract;
• neoplasms in the kidneys;
• liver cancer;
• enlargement of the pituitary gland.

Reference! In 95% of cases, an increase in hCG in men indicates an oncological disease of the genitourinary system. The fact is that the neoplasms contain embryonic tissue, which actually produces hCG.

A low level of hCG does not pose a danger to human health and life and is considered normal.

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.