Women who are planning a baby try to see the first signs or symptoms of pregnancy in themselves long before they actually appear. Many expectant mothers begin to do tests almost immediately after the expected ovulation, so they want to quickly see the cherished two strips. But today, the most accurate way to determine pregnancy in the early stages is to test for hCG. Various factors influence the growth rate of this hormone. We will talk about how hCG in the urine increases after conception in our article. We will definitely dwell on when you should start doing pregnancy tests at home and how else you can find out the level of this hormone in the body.
What is HCG?
The full name of this hormone is: human chronic gonadotropin. It begins to be produced by chorion cells already in the first hours of pregnancy - immediately afterembryo implantation. This usually happens a week after the actual fertilization of the egg.
According to its chemical structure, hCG consists of alpha (α) and beta (β) subunits. The latter value is unique to this hormone. It is in the presence of hCG in blood or urine tests, namely the beta subunit, that one can judge the implantation of the egg to the uterine wall. This is what home pregnancy tests are based on.
If a woman is not pregnant, chronic gonadotropin is absent in the body. As an exception, it can be produced by various malignant tumors, both in women and in men.
The role of the hormone in a woman's body
In the normal state, hCG is absent in the urine. But a blood test can show the presence of this hormone in the body, but its concentration is no more than 5 mU / ml. Active growth of hCG occurs 6-8 days after fertilization. It plays the following role in a woman's body:
- Participates in the development and maintains the functionality of the placenta, helps to increase the chorionic villi.
- Prevents resorption and ensures the activity of the corpus luteum until the 12th week of gestation, until the placenta independently produces progesterone and estrogen in the right amount. Without these hormones, a successful pregnancy outcome is impossible.
- Prevents early miscarriages as a result of a negative reaction of the body to a foreign organism inside the uterus. This is especially true if the Rh factor of the embryo differs from that of the mother.
HCG level should be normalmatch the gestational age. The deviation of the indicator in one direction or another is the reason for a thorough examination of the mother and fetus.
How HCG rises during pregnancy
With the successful development of pregnancy, there is an intensive growth of human chorionic gonadotropin in dynamics. Starting from 6-8 days and up to 11 weeks of gestation, this figure increases several thousand times, and then gradually decreases. A sharp decrease in the value of the indicator or a slowdown in growth may indicate a miscarriage or ectopic pregnancy.
Elevated levels of hCG in the urine may indicate that the woman has an incorrect gestational age, or be one of the signs of the following conditions in the body:
- multiple pregnancy (higher than normal hCG growth is proportional to the number of embryos);
- Chromosomal abnormalities in the fetus (with a simultaneous decrease in PAPP-A plasma protein-A);
- when the mother-to-be has diabetes;
- with the development of late toxicosis (preeclampsia);
- Woman taking some synthetic hormonal drugs.
Determining the level of hCG in the blood
It is possible to determine the presence of human chorionic gonadotropin in the body both by urinalysis and by a blood test. In the first case, the study is most often performed at home using pregnancy tests. An analysis for the determination of hCG in blood serum is carried out exclusively inlaboratories.
For research, a woman takes blood from a vein on an empty stomach in the morning. The last meal the day before should be no later than 6 pm. Before taking the test, it is not recommended to drink coffee, tea and other drinks. In addition, the patient is advised to refrain from:
- alcohol;
- greasy and spicy food;
- physical activity;
- sexual contact.
If a woman is taking any medications, including hormonal ones, she must inform the laboratory assistant about it. The result of the analysis can usually be obtained within two hours after delivery.
HCG levels in urine during pregnancy
Analysis to determine the value of human chorionic gonadotropin allows you to establish the fact of pregnancy. Its accuracy reaches 98%. This is the easiest test to determine pregnancy. In other cases, it is carried out after artificial termination of pregnancy, with suspicion of the development of a tumor in the body, dysfunctional bleeding in the uterus.
For analysis, a morning portion of urine is taken to the laboratory. The concentration of hCG in it is determined using special reagents. Based on the results of the analysis, one can judge the presence and estimated duration of pregnancy. If there are deviations up or down, the doctor should prescribe an additional ultrasound of the pelvic organs and blood donation for hCG.
Preparation for laboratory analysis
Analysisfor the determination of hCG in urine can be considered reliable if the following conditions were met before it was performed:
- refusal to have sex at least 12 hours before the delivery of the material to the laboratory;
- using a sterile container to collect biomaterial;
- delivery of urine to the laboratory within 2 hours after collection.
For analysis, it is necessary to collect an average portion of morning urine. Before this, it is necessary to carry out hygiene procedures, and close the vagina with a swab. This will prevent the secretions from entering the urine. On the eve of the test, it is recommended to stop eating foods that stain the color of the body fluid, such as beets.
Norm HCG in urine by day after ovulation
It is not advisable to test for the detection of human chorionic gonadotropin in the urine earlier than 7 days after the expected ovulation. Even if fertilization has already occurred, the concentration of the hormone in the body will be too low. On average, on day 8, the egg is attached to the walls of the uterus, resulting in a sharp increase in the level of hCG. Even the most sensitive tests will be able to determine pregnancy at this time.
How the level of hCG in urine changes by day can be found in the table.
| The day after ovulation | HCG level, honey/ml |
| min-max | |
| 7-8 | 2-18 |
| 9-10 | 5-26 |
| 11-12 | 11-65 |
| 13-14 | 22-170 |
| 15-16 | 39-400 |
| 17-18 | 120-840 |
| 19-20 | 370-2000 |
Thus, already in the first week after ovulation, the concentration of homon in the urine increases at least 10 times. On the 42nd day from conception, hCG in the urine can reach 128,000 mU / ml. The highest concentration of the hormone in the urine is usually observed at 8-9 weeks of pregnancy.
What to do if the hCG level is below normal?
In such a situation, you should immediately consult a doctor. Low hCG in the urine during pregnancy may mean that the gestational age is set incorrectly. The gynecologist will examine the patient and give a referral for an ultrasound examination. This will allow you to assess which week of gestation corresponds to the development of the embryo. Perhaps ovulation was late and, accordingly, fertilization occurred a few days later than the expected date. In this case, the ultrasound will show that the woman has absolutely nothing to worry about.
In addition to incorrect determination of the gestational age, low levels of hCG can also indicate serious disorders in the body:
- ectopic pregnancy;
- anembryony;
- fetal growth retardation;
- threatened miscarriage;
- placental insufficiency;
- Intrauterine fetal death (after 24 weeks of gestation).
If the reason for the decrease in chorionic gonadotropin is the threat of spontaneous abortion, the doctor prescribes to the womanhormone therapy to increase the chances of the embryo surviving.
HCG determination at home
To find out if there is a pregnancy or not, it is not necessary to run to the laboratory. This can be done at home as well. Special pregnancy tests are based on the detection of the beta subunit of hCG in the body. They have different sensitivities (from 10 mU/ml and above). Thus, based on the data in the table above, pregnancy can be detected even before the delay of menstruation, starting from the 7th day after ovulation.
At the heart of every pregnancy test is the reaction of a reagent with urine. If the hCG hormone is present in the body, the reagent will react by the appearance of a second strip on the test. False-negative results are possible in early pregnancy. This happens when implantation has already occurred, and the test does not show a second strip. In fact, there is no need to get upset in advance. It is possible that ovulation occurred later, and the sensitivity of the test is too high to determine early pregnancy. This is the reason why doctors do not recommend doing home tests before your missed period.
Pregnancy tests
The pharmaceutical industry offers several types of home tests to consumers:
- Stripes. This is the simplest and most accessible test model. On one side of such a strip, a reagent sensitive to hCG is applied. When performing the test, it should be lowered into a jar of morning urine to the indicated mark, and then placed on a flat surface.surface. It will be possible to evaluate the result in 5 minutes.
- Inkjet. Such a test does not need to be lowered into a container with urine, it is enough to substitute it under the stream during morning urination.
- Electronic (digital) test. It has the highest sensitivity and can show pregnancy for 1-2 weeks (7-14 days after ovulation). The test result can be seen on the scoreboard.
It is worth noting that none of the presented tests shows hCG in the urine by day. The most accurate result can only be obtained after passing laboratory tests.
