When an egg is fertilized and attached, a special hormone, hCG, begins to be produced. The presence of human chorionic gonadotropin in the urine or blood of a woman can indicate pregnancy.
General information about the hormone
HCG in a woman's body begins to be produced from the moment of conception, but at first its concentration is so insignificant that it cannot be detected. At the moment of fertilization of the egg, the shell begins to form. It is her cells that can produce this hormone.
You can identify it by conducting a laboratory blood test. You can also find out about the fertilization of the egg and the attachment of the embryo using a regular home pregnancy test. A blood test allows not only to diagnose pregnancy, but also to figure out if it is proceeding normally. But for this you need to know what hCG results for what period should be.
Assign this analysis for the purpose of early diagnosis of pregnancy. Indeed, compared with conventional home tests, this method is considered more informative. This study will also help determine the statusplacental function. It allows you to identify violations in the uterus-fetus system.
Interpretation of analyzes
In the blood, chorionic gonadotropin can be detected as early as 7-10 days after fertilization has taken place. When pregnancy occurs at this time, the concentration of this hormone exceeds the established negative norms of 0-5 units.
But it is better to donate blood after a delay. After all, the concentration of hCG begins to increase markedly only after implantation. For most women, this happens on the 7th day after fertilization. But there are cases when the fetal egg is implanted in the wall of the uterus 2-3 days later. If you take an hCG test at this time, it will be negative.
Therefore, gynecologists advise to wait for the expected date of menstruation and only after that go to the laboratory. This way you can get the most reliable results.
If on the expected date of menstruation hCG is negative, and critical days do not occur, then you can retake the analysis in 3-5 days. Perhaps ovulation was delayed and the egg was fertilized a few days later than the expected date.
HCG results allow you to find out the duration of pregnancy. If you take this analysis in dynamics with a certain frequency, then you can understand whether the baby is developing normally in the womb. This is determined by the dynamics of growth in the concentration of this hormone. Normally, it should double every 2-3 days. But it makes sense to follow it only up to 9 weeks, after this period its concentration may begin to decline.
Definitionpregnancy
After donating blood for analysis, women often cannot wait until the result is already there. HCG is negative if its concentration is in the range of 0-5 units. Pregnancy is indicated by indicators above 25 units.
But it happens that a woman receives a response indicating that the concentration of hCG ranges between 5 and 25 units. This is the so-called gray area. It is impossible to unambiguously say from such an analysis that pregnancy has occurred. Indeed, such indicators may indicate that fertilization has occurred recently, and the amount of the hormone has not yet had time to increase to the required level.
In addition, such results of hCG may indicate that the egg was fertilized, but could not attach to the wall of the uterus. In this case, you need to wait for menstruation. If it does not start, it makes sense to retake this analysis. At the same time, it is important to look at the dynamics of indicators. After all, such a result may indicate an ectopic implantation of the fetal egg.
If the hCG hormone is present in an amount of more than 25 units, then the egg, most likely, has already attached. For up to 2 weeks, counting from the date of conception, the level of chorionic gonadotropin should be in the range of 25-156 mU / ml. Its concentration increases quite quickly.
Check if the gestational age corresponds to the results of the tests, the hCG table will help.
| Estimated due date from conception/last period | Hormone concentration, honey/ml |
| 1-2/3-4 | 25-156 |
| 2-3/4-5 | 100-4 870 |
| 3-4/5-6 | 1 111-31 500 |
| 4-5/6-7 | 2 500-82 400 |
| 5-6/7-8 | 23,000-151,000 |
| 6-7/8-9 | 27 300-230 000 |
| 7-11/9-13 | 21,000-291,000 |
| 11-16/13-18 | 6 100-103 000 |
| 16-21/18-23 | 4 720-80 000 |
| 21-39/23-41 | 2 700-78 100 |
If the period set in the laboratory based on the results of the tests does not match the one you have, then you should additionally consult a gynecologist and go for an ultrasound.
Possible causes of increased hormone levels
In some cases, women get results that do not match their expected gestational age. The concentration of the hormone can be either more than the established norm, or less than it.
If you get an hCG test result that has higher than expected levels of human chorionic gonadotropin, this may indicate:
- multiple pregnancy;
- the development of diabetes in a future mother;
- wrong gestational age;
- possible developmental pathologies, for example, Down syndrome or multiplevices.
In addition, elevated levels of hCG can be with the development of toxicosis in the early or preeclampsia in late pregnancy. Taking synthetic progestogens also affects its concentration.
There are cases in which the level of gonadotropin increases without pregnancy. His growth is stimulated:
- tumor diseases in the gastrointestinal tract;
- neoplasms in testicles;
- tumors in the uterus, lungs, kidneys;
- taking hCG drugs.
Also, the hCG value can be high with a mole. This is a situation in which the embryo does not develop, but the chorionic villi begin to actively grow. It can transform into a malignant tumor. Therefore, it is important to remove it in time.
Having received the first positive results of the analysis, it is important to monitor the intensity with which the concentration of the hormone increases. The hCG table makes it possible to verify whether the calculated gestational age corresponds to that determined in the laboratory. And the growth dynamics determine the uterine location and viability of the embryo.
Reasons for a decrease in hCG levels
It is not uncommon for the concentration of the pregnancy hormone to be reduced. The safest is the situation in which the timing discrepancy can be caused by an error in the calculations. This is often the case in women with irregular cycles. After all, the date of ovulation is quite difficult for them to determine. Deviations of 5-7 days will already be very noticeable. To confirm that everything is fine with pregnancy, the dynamics of hCG will help. If the hormone concentrationwill double every 2-3 days, then there is no cause for concern.
In the early stages, a decrease in hCG levels can be caused by:
- threat of miscarriage (if the placenta is detached, the hormone level can decrease by 50%);
- incorrect implantation of the embryo (it can attach in the fallopian tubes, cervix, ovaries or even in the abdominal cavity);
- a missed pregnancy, in which intrauterine death of the embryo occurs.
In the second or third trimester, the concentration of the hormone may also decrease. In this case, blood is not donated in order to determine the timing. HCG can tell about placental insufficiency. If the amount of the hormone is reduced, then this may indicate a violation of the blood supply between the fetus and the mother. But making a diagnosis based on a single test result is wrong.
Also, the concentration of the hormone will be less with intrauterine death of the fetus. Ultrasound is required to confirm the diagnosis. When pregnancy is prolonged, the concentration of chorionic gonadotropin also decreases. This is due to the fact that the functions of the chorion are gradually fading away.
Preparing for analysis
Despite the fact that hCG may be positive already a few days before the expected date of menstruation, gynecologists recommend waiting for a delay. At this time, it will be possible to understand exactly by the result whether fertilization has occurred.
For diagnosis, the laboratory assistant takes venous blood. Therefore, it is important to go to this study on an empty stomach. Blood sampling is carried outin the morning hours. The night before, you should stop eating fatty foods. Strenuous exercise should also be avoided.
Before the study, it is necessary to warn the doctor about taking various medications. Some of them may not affect test results.
If a woman was stimulated to ovulate and injected with the synthetic hormone hCG, then it is better to wait a little with blood donation. After all, the body will need time to fully remove it. In this situation, it is advisable to wait a few days after the delay and take the test at least twice in 1-2 days. This will allow you to track the growth dynamics of hCG by week and confirm that pregnancy has occurred.
Deviation from the norm: is it worth panicking
Not always a woman gets a result that matches her gestational age. In this case, she needs to immediately go to the gynecologist, even if she has not yet had time to register. Each situation must be de alt with individually. Elevated levels of hCG can indicate both a multiple pregnancy, an incorrectly set period, and various problems. The doctor should prescribe additional studies to check if everything is fine with the woman. But first of all, it is necessary to conduct an ultrasound examination.
With a low concentration of the hormone, you also cannot do without consulting a doctor. The doctor will help clarify the gestational age and check whether it corresponds to the indicators determined in the laboratory. Considering that the level of hCG decreases with the wrongimplantation of the fetal egg, with the threat of miscarriage or missed pregnancy, it becomes clear why the specialist prescribes additional examinations: it is better to play it safe.
First of all, such women are sent for ultrasound. Depending on its results, it is determined whether something threatens the expectant mother and her baby. If a fetal egg is not found in the uterus, but hCG exceeds 1000 units, they speak of an ectopic pregnancy. In this case, the fertilized egg must be removed urgently.
In case of threatened spontaneous abortion, preservation therapy is prescribed. It is not uncommon for a woman to stay in the hospital under medical supervision until her condition improves.
If the level of hCG does not noticeably differ from that which should be at such a period, and the heartbeat is not visualized on the ultrasound, this indicates that the embryo may have stopped developing. Further tactics of actions depend on the term. If no more than 1-2 weeks have passed after the delay, then the analysis must be retaken in dynamics. Perhaps ovulation occurred later, and the estimated gestational age does not correspond to the real one.
Re-take tests
What does hCG mean, we figured it out. A study of its level can be carried out after 2-3 days in the first weeks of pregnancy. If it doubles, then there is no cause for concern. But what if the indicators increase very slowly? In such a situation, it is better to consult a doctor. Only a specialist can find out the reason that led to the fact that the concentration of the hormone does not increase proportionallydeadline.
Most often, poor dynamics is observed in ectopic pregnancy. The concentration of the hormone may increase, but its doubling every 2-3 days is out of the question. The membranes of the embryo produce hCG, but not as actively as it does during normal egg implantation. As a rule, during an ectopic pregnancy, the level of hCG can rise 2 times in a week.
Also, the dynamics can worsen with the threat of a miscarriage. In this case, it is important that the woman be given adequate preservation therapy in time. In most cases, pregnant women are prescribed progesterone preparations (Dufaston, Utrozhestan) and strict bed rest is recommended. Doctors also prescribe antispasmodics and mild sedatives.
When a missed pregnancy hCG will not rise. If you take tests at regular intervals, you can see that its level is falling. The shorter the gestational age was at the moment when the embryo stopped developing, the faster the indicators will decrease. But in all cases, it is desirable to conduct the study in the same laboratory.
Performing express diagnostics
You can determine if you managed to get pregnant at home. To do this, use special tests that react to the presence of a hormone in the urine. Some manufacturers produce devices that allow you to find out the approximate dates. HCG in the urine increases in the same way as in the blood. But such tests are not cheap.
Even with the help of such home diagnostics, it is possible to determine exactly whetherfertilization of the egg. How pregnancy develops can be judged by the intensity of the color of the strip on the test. If on the first day of the delay it can be weak and barely noticeable, then after a week it will have the same color as the control band.
But if it does not get brighter, then this is an occasion to donate blood to determine the level of the hormone. After 6 weeks (counting from the last menstruation), it will already be possible to see the embryo and heartbeat on ultrasound. The lack of dynamics may indicate a missed pregnancy or ectopic implantation of the fetal egg. But it is impossible to draw such conclusions without ultrasound diagnostics and checking hCG by weeks. It is also worth noting that different tests may have different sensitivity and dye concentration.
Features of interpretation of results
Despite the fact that upon receipt of the test form, a woman can see both her indicators and the hormone rate for each period, you should not interpret them yourself.
In case of any deviations, it is important to assess the general condition of the pregnant woman. Additional diagnostic methods become mandatory. Either way, an ultrasound will be needed. Only with such a study can you see the fetal egg and the embryo if they are in the uterus. With the help of ultrasound, an ectopic pregnancy is also determined. It will be indicated by the absence of a fetal egg in the uterus and the accumulation of free fluid outside it.
If you get too low hCG results, do not immediately despair. It is important to look at the dynamics and seeindicator growth. Before donating blood, it is necessary to clarify the expected gestational age. If this is not done, then the laboratories may not indicate exact results, but simply write that the concentration of the hormone is greater than a certain indicator (for example, more than 1000). Indeed, in this case, the laboratory assistant simply determines whether there is a pregnancy. When specifying the week of pregnancy, the study will already calculate exact numbers to check whether the estimated dates correspond to those determined in the laboratory.
In addition, a woman should be aware of the signs that may indicate problems. These include nagging pain in the lower abdomen and back, smearing brown or bloody discharge, a noticeable deterioration in well-being.
