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How does the test work
If you do the test too early, you can get a negative result. Therefore, do not rush to use it immediately after sexual intercourse. The test works on a simple principle. It is made in the form of a strip and has two lines impregnated with a special substance – a reagent. A woman should collect some urine and put a test strip in it. When urine gets on the strips, they appear. One becomes visible in any case, and the second – only during pregnancy. Thus, the test responds to the content of the hCG hormone or pregnancy hormone. If conception occurred, the test will show two bright stripes.
What is the hormone hCG
This chorionic gonadotropin, which is produced after conception. It produces chorion. If fertilization and egg implantation have occurred, then the woman begins to produce a hormone. It is detected in the blood and urine of a pregnant woman. Having done a blood test, the doctor can determine the presence of chorionic tissue in the body of a woman. This serves as confirmation of pregnancy. Detection of hCG in the blood makes it possible to determine the pregnancy within a week after fertilization. The role of this hormone is very high. It stimulates the formation of other hormones that are necessary for the normal development of pregnancy and the fetus: progesterone, free estriol, estradiol, etc.
Hormone hCG after conception
After attaching the egg to the wall of the uterus, the level of the hormone HCG begins to increase steadily. It doubles every day. There are women whose hCG levels rise more slowly than others. For example, every 36 or 48 hours. The highest level of hormone is observed 10-12 weeks after fertilization. Then it decreases and in the second half of the term remains at the same level.
In some cases, hCG remains elevated and in the absence of pregnancy. This happens if the test is carried out after an abortion after 4-5 days or because of the use of special preparations of hCG. If the hormone level does not decrease after a mini abortion, this indicates that the pregnancy continues. A low content of hCG in a pregnant woman indicates an incorrect determination of pregnancy. Sometimes it says about problems in the body:
- pregnancy does not develop;
- the threat of miscarriage and spontaneous abortion;
- developmental delay in the fetus;
- ectopic pregnancy;
- fetal death, etc.
It is necessary to take into account the fact that the fertilized egg is usually attached to the wall of the uterus no earlier than 2 weeks after ovulation and fertilization. Therefore, manufacturers test advised to perform them only after the delay of the next monthly. A fetal egg can attach to the wall of the uterus from the 3rd to the 13th day after conception. Therefore, the results can vary: in some women, a positive test is observed a week before the menstruation, while in others, even after 3 days after the delay, only one strip appears. Therefore, it is difficult to give an unequivocal answer to the question: “After how many days can a pregnancy test be done?”.
It is possible to diagnose pregnancy only after a certain time after conception. At the time of implantation of the ovum, the level of the hormone HCG is very small. But it grows daily. Therefore, waiting for 5 days after the delay of menstruation, you can accurately diagnose pregnancy. The hormone hCG is produced with different intensity in different women, it must also be taken into account. If implantation occurred 11-12 days after ovulation, then a positive result can only be enjoyed 2 weeks after fertilization. If ovulation has occurred in the middle of the cycle (2 weeks before the menstruation), then it will be possible to determine whether a pregnancy has occurred or not only on the first day of the delay.
When making a test, some women face a situation where one strip becomes bright and the other becomes dull. Thus, the second strip is present, but it is faded. In this case, too, they say a positive test result. Just the urine pregnancy hormone is still very small. The reason may be that the woman drinks too much fluid, which reduces the concentration of the hormone in the urine.
Highly sensitive pregnancy tests
If conception has occurred, by the first day of the proposed menstrual cycle, the hormone hCG in the blood of a woman increases to 100 mIU / ml. In the urine, the concentration of this hormone is 2 times less. Highly sensitive test strips are able to respond to gonadotropin when its concentration is 10 mIU / ml. Therefore, such tests can be done early, without waiting for the delay. The most sensitive tests make it possible to obtain accurate results several days after the attachment of the ovum to the endometrium. All tests of this type are immunochromatographic. It is very easy and convenient to use them. There are test strips, cassettes and inkjet. They have an increased sensitivity and give accurate results by 99.9%. Tests may have the following sensitivity:
- 10 mIU / ml;
- 20 mIU / ml;
- 25 mIU / ml.
The lower the sensitivity index, the earlier you can learn about pregnancy with a test. In the early stages, tests that say 10 mIU / ml can tell about conception.
Any test must be repeated. Whenever it is conducted, it must be re-executed. After how many days can I take another pregnancy test? Do this procedure 2-3 days after the first test. This will allow you to be confident in the results. It is also necessary to visit a gynecologist, if menstruation has not come.
How to perform a pregnancy test
To get accurate results, it is recommended to do a test for morning (first) urine. The amount of hormone HCG in the urine during this period reaches a maximum. If you have failed to use the first urine, then the test can be done at any other time. Before that, it is advisable to refrain from using the toilet for several hours. This advice is relevant for those who want to learn about pregnancy before the delay of menstruation. In addition, you can do several tests. At least one of them will be able to determine early pregnancy.
Despite the fact that manufacturers offer highly sensitive tests, experts say that they are not as effective as the diagnosis of laboratory blood tests. Therefore, if you want to know about an interesting situation as soon as possible, you should donate blood for analysis. In the blood, the hormone hCG is detected much earlier than in the urine.
If a woman performs the test 3-4 weeks after conception, the result is beyond doubt. At this point, the content of hCG in her body is very high. Test strips are equally sharp and bright. If the pregnancy is multiple, then the hormone level will be much higher. This allows you to diagnose pregnancy earlier.