Determining the hCG level by days from conception allows you to detect pregnancy pathologies in time or make sure the fetus is developing normally. The analysis is carried out by most private and public clinics, which makes it as accessible as possible. The minimum duration of the study is 4 hours, and the maximum does not exceed 1 day.
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What is hCG
Human chorionic gonadotropin is abbreviated as hCG. This is a hormone synthesized in women after zygote is fixed in the uterine epithelium. Usually this process proceeds in the first 7 days from conception.
HCG triggers the formation of female sex hormones (estrogen and progesterone) in the corpus luteum. Moreover, he is also responsible for its safety.
This is necessary for adequate ripening of the fetus and its bearing. Such a system works until the complete formation and start of functioning of the placenta. Then its influence is sharply reduced.
What is the analysis done for and when
A blood test for hCG is performed to determine the fact of pregnancy. It is also used to diagnose its development. It allows us to differentiate a normally developing fetus from a frozen one, and also to suggest its ectopic localization. It is especially important to control the concentration of chorionic gonadotropin in IVF. This will make it possible to evaluate the success of the protocol and the number of implanted embryos.
Chorionic gonadotropin has 2 subunits - α and β.Its first part is similar to that of substances produced by the pituitary gland (follicle-stimulating, thyroid-stimulating and luteinizing hormones), due to which the corpus luteum works for short periods. And the second subunit is unique. On it and determine its content in urine or blood.
For quick home diagnostics, test strips are used. They allow you to know the level of hCG in the urine. Its maximum concentration is detected in the morning hours, so the study should be done at this time. If the norm is exceeded, the analysis will show a positive result, which will mean pregnancy. But to find out in this way the exact date of fertilization or the growth dynamics of the hormone is impossible.
To accurately determine the amount of hCG, a blood test is performed. He will show the result after 6 - 10 days from the day of fertilization.
Since the measurement is carried out by a quantitative method, this allows you to track the dynamics of concentration growth. In this way, the degree of development of pregnancy is estimated, and also based on the data obtained, it is possible to assume the number of embryos in the uterus before they become visible on ultrasound.
At the first prenatal screening, they also look at the level of β-hCG. Its concentration may change in the presence of a chromosomal disease in the fetus. This is an important diagnostic factor, it allows to reduce the number of children with disabilities and gives parents the opportunity to choose with a positive test of genetic examination for developmental disorders.
How does hCG change by day of pregnancy
In pregnant women, the level of hCG in the early stages increases every 2 days by 2 times. The maximum number is noted in 5 - 8 weeks. Then his level drops. This pattern makes it possible to track the development of the embryo when it is still not sufficiently noticeable with ultrasound.
Normal performance
The content of chorionic gonadotropin is measured in honey / ml.
The approximate concentrations determined in the blood during a one-year pregnancy can be presented in the form of a table:
| period (weeks) | hCG concentration (thousands of units) |
|---|---|
| Women who do not bear a child and men | Up to 0.005 |
| 1 − 2 | 0.025 to 0.3 |
| 2 − 3 | 1.5 to 5.0 |
| 3 − 4 | 10 to 30 |
| 4 − 5 | From 20 to 100 |
| 5 − 7 | 50 to 200 |
| 7 − 8 | From 20 to 200 |
| 8 − 9 | ... up to 100 |
| 9 − 10 | ... up to 95 |
| 11 − 12 | ... up to 90 |
| 13 − 14 | From 15 to 60 |
| 15 − 25 | 10 to 35 |
| 26 − 37 | ... up to 60 |
HCG rates are exemplary and may be adjusted depending on which day of the cycle of fertilization.
With late ovulation, they will be slightly lower, so it is more important to monitor the dynamics of changes. With a regular doubling of the amount of the hormone, pregnancy is considered to be proceeding normally.
During a frozen pregnancy
If embryo development stops, the amount of hCG stops growing exponentially. Concentration may increase too slowly, not change or gradually decrease. This is due to how many weeks the embryo has grown. The pathological dynamics of the hormone is always considered an indication for urgent treatment in a specialized medical institution. It will help to avoid possible complications of a missed pregnancy and fetal death in the womb when passing from conception for more than 23 weeks.
HCG levels at double
Chorionic gonadotropin is synthesized to continue pregnancy. With twins, its concentration increases exactly as many times as there are embryos in the uterus. But this is true only for the first analysis of hormone levels. During dynamic observation, the same pattern will be observed as in a singleton pregnancy: the number of hCG grows 2 times every 2 days.
What is low or high
The number of hCG can vary in any of the parties. Its deficiency is noted with an ectopic pregnancy or a dead one, the threat of miscarriage, insufficiency of uteroplacental blood flow. Also, this condition is characteristic of late ovulation, when the period of conception is later than doctors suggest. But the presence of this deviation is considered an occasion to seek medical help and conduct additional examinations.
A high concentration of chorionic gonadotropin is not unambiguous.
It can occur in several conditions:
- the number of fruits is more than one;
- prolonged pregnancy;
- early ovulation, as a result of which the term of probable fertilization is determined incorrectly;
- the presence of a chromosomal disease in the embryo (developmental abnormalities, Down syndrome and other pathologies);
- preeclampsia - toxicosis in pregnant women;
- treatment with progestogen analogues.
Not that the content in the analysis for hCG is no reason to panic or suggest an unpleasant outcome. Cases of inaccurate calculation of the term of gamete fusion or detection of several embryos are noted much more often than adverse episodes. But to ignore this fact is also not worth it, because early diagnosis of pathologies allows you to avoid complications associated with them.
The level of hCG in the blood rises earlier than in the urine, and the result of the study is more accurate. It allows you to learn about fertilization even before the delay of critical days.
Therefore, it is often used by women for whom the conception of a child is a long-awaited event. Ultrasound up to 7 - 8 weeks is carried out transvaginally, which is undesirable for such a period, and analysis of the concentration of chorionic gonadotropin can calm anxious expectant mothers, "reporting" that the embryo is in the uterus and their health is not in danger. This is a modern, safe and accurate diagnostic method, the popularity and credibility of which is growing every year.
