When to do a pregnancy test
Modern tests allow us to determine pregnancy in the shortest possible time after a “suspicious” intercourse. But this cannot be done earlier than is possible in principle. And in order to correctly answer the question posed, it is necessary to deal with the processes occurring after the meeting of the spermatozoon and the egg cell.
How does a pregnancy test work
So, we know that after fertilization has occurred in the blood of a woman, the level of the hormone HCG begins to increase, which indicates the presence of pregnancy. Having identified this substance, the test shows us a positive result – two strips. In fact, the test responds to the presence of hormone gonadotropin in the urine: when the level of hCG rises, the reagent on the second test strip appears.
HCG in the body of a pregnant woman is produced immediately after embryo implantation into the uterus wall, first in the blood and a little later in the woman’s urine, and usually in the urine it is in lower concentration than in the blood. Implantation, in turn, occurs on the 7-10th day after ovulation. But it must be borne in mind that the level of the hormone increases gradually, increasing daily, until it reaches a certain level, which the test is able to fix. This moment determines the time frame. That is, the test is able to “detect” the presence of the hormone gonadotropin in the urine of a pregnant woman no earlier than after 11-15 days after the day of the last ovulation. The lower the threshold of sensitivity of the test, the earlier it will be able to determine the pregnancy and the more expensive it is. Tests with a sensitivity of 10 mIU / ml (as a rule, jet tests fall into this category) are able to determine the pregnancy that took place several (up to five) days before the expected menstruation. Tests with a sensitivity of 25 mIU / ml (strip stripes) determine pregnancy starting on the first day of the delay. But this is statistics. And there are also individual cases with early or late implantation. Therefore, a premature test can often be wrong.
See also High Sensitivity Pregnancy Test.
When to do a pregnancy test with an irregular cycle
The probability of a test error is especially high if the woman has an irregular menstrual cycle. A test carried out ahead of time in this case may show false-negative results, because the gestational period may be very small so that the reaction bar will work. A pregnancy test error is all the more likely than the test was previously performed.
Pregnancy test with an irregular cycle does not make sense to hold until the delay. The earliest time when it can be done is two weeks after ovulation, and the longest cycle should be taken as a reference point. If you do not monitor this process, then it is recommended that the test be carried out after a delay, and in order to be more reliable, it is best to repeat the test again after a week or two. Regarding what time of the day testing should be done, read the article “Pregnancy test – when to do it: in the morning, in the afternoon, in the evening?”.
How to make a pregnancy test
Regardless of the regularity of the cycle and other features of the female body, the reliability of the test will be the higher, the clearer the rules for its conduct will be. Any violations of the instructions may cause false results.
It is believed that in the morning the pregnancy test shows the most reliable results, since the concentration of hCG in the morning urine is the highest. But if the delay is already large, then the test can be done by and large at any time of the day.
A prerequisite is compliance with the rules of sterility: no foreign substances in the test liquid should not fall, and therefore the hands must be thoroughly washed and wiped dry beforehand. Also prepare a sterile collection vessel well in advance.
The test strip should be immersed in a vessel with urine only to the level indicated on its canvas, and always on the side where indicated (where the reactive substance is contained).
You should not evaluate the test result before the time specified in the instructions (usually, it is 5 minutes) or much later. After a long period of time, the results of any test are considered invalid.
When to do a pregnancy test: reviews
How does the test work?
Currently, to get a pregnancy test is not difficult. This indicator, designed for self-diagnosis of the presence or absence of pregnancy, is sold in any pharmacy. The reliability of the results obtained with this remarkable invention reaches 90%. However, many women, relying on their own knowledge, do not bother themselves with reading the instructions attached to the test. As a result, the results of the pregnancy test are not always true.
The test for determining pregnancy is a strip of cardboard, the surface of which is coated with a special reagent. The principle of home diagnosis of pregnancy is as follows. Immediately after fertilization, a special hormone hCG, chorionic gonadotropin, begins to be intensively produced in the female body. If a woman’s urine contains an increased amount of the hormone hCG, then when it hits the test, a corresponding reaction occurs – the strip changes its color, which confirms the presence of pregnancy.
When a sensitivity test of 25 mUI is used (an indicator of hormone levels), it is necessary to take into account that after ovulation the hormone level rises gradually. Therefore, the test will show the correct result, starting from the 11th day after the ovulation occurred. It is worth considering that the blood test is a more accurate and reliable option, since the content of the hormone in the urine is much lower and this indicator depends on many individual characteristics of the body of each individual woman. In addition, there may be early or late implantation – respectively, and the timing of the increase in the level of the hormone may shift. On average, after ovulation, implantation occurs after a week (with a cycle of 28 days), but there are significant differences.
A negative result of any test may be due to the fact that it was done before the onset of menstruation, when the level of the hormone in a woman’s body has not yet exceeded the norm. Therefore, it is recommended after several days to repeat the test (starting from the day of delay of menstruation). You can use tests with a sensitivity of 10 mUI – they are more sensitive and accurate, but also cost more. Such tests determine the occurrence of pregnancy even before the delay of menstruation.
Sometimes tests show a positive result, if from a previous pregnancy in the uterus after an abortion or miscarriage, the remains of the ovum remain – therefore it is better to consult a doctor if you suspect this. A fuzzy second strip on the test confirms the pregnancy – while the concentration of the hormone in the urine is low, this explains the pale color of the strip.
When to do the test?
Some women believe that it is possible to use the test to determine pregnancy after ovulation until the delay of menstruation, because an increase in the level of human chorionic gonadotropin occurs already in the first week after fertilization. This is not entirely true. It should take 10-14 days for the hCG hormone to reach a concentration at which the test strip could react to it. The test is not sensitive to the minimum amount of this hormone. Therefore, the most optimal time to determine pregnancy with the help of a test strip is the first day of the delay of menstruation.
It is necessary to use the test in the morning, after the woman has woken up – this will ensure the optimal concentration of the hormone in the urine. The use of a special inkjet test is possible during the day or in the evening.
If after the alleged conception blood began to be released, then the test should be done after dubious “menstruations”. Once the test has confirmed the pregnancy, the woman should immediately contact a gynecologist, since bleeding can be a signal of the risk of abortion.
Currently, there are already new, improved, determinants of pregnancy, for example, inkjet tests. They have a higher threshold of sensitivity, so a positive result can be obtained as early as 5 days before the start of the menstrual cycle. The inkjet test is a receiver rod (cassette) equipped with a reagent, a holder and a protective cap. Its main difference from the test strip is that this indicator for determining pregnancy is only necessary to hold under the stream of urine. This method of home diagnostics is much more convenient, since it does not require spending time searching for a suitable container and keeping the test in the urine. However, it should be borne in mind that compared to the strips, the cost of the jet test is much higher.
Features of a pregnancy test
Of course, a pregnancy test on the first day of a delay is recommended. The body of each woman is different, so the timing of the onset of ovulation and further implantation of the egg can vary. In addition, much depends on mood fluctuations, stress, age-related changes, concomitant ailments, immunity and even from atmospheric influences.
Doubtful results are possible, including due to the poor quality of the tests, the expiration of their shelf life, their incorrect use, or too early. It is undesirable to drink too much liquid on the eve of the test – this can significantly reduce the concentration of the hormone in the urine. The results may also be affected by the presence of certain hormonal changes in the body, the use of anti-sterility drugs.
To get a reliable result, the main thing is to follow certain rules when conducting a pregnancy test after ovulation. It is necessary to carefully study the instructions, do not allow dirt and moisture to enter the test, do not touch the place of application of the reagent, do not use the indicator at the end of its storage period. If everything is done correctly, then it is quite possible to rely on the test result. Good luck, future moms!
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When to do a pregnancy test after ovulation
Fertilizing a woman is an amazing process that gives rise to a new life. Already after 3-6 hours after sexual intercourse in the period of ovulation, we can safely talk about the beginning of pregnancy, if the sperm cell penetrated the egg cell. Lightning in the body of a woman begins a variety of chemical processes that reconfigure the body to preserve pregnancy.
But a woman is interested in something completely different – when to do a pregnancy test after ovulation? After all, we all know that the pregnancy test responds to a special hormone of pregnancy in the urine of a woman – hCG, which, after implantation of a fertilized egg, begins to actively double in each day.
Implantation of a fertilized egg occurs about a week after fertilization. Exactly from this period the real pregnancy begins. The implantation itself lasts about 40 hours, but somehow it just happened, the zygote cells begin to divide very quickly. Blood vessels appear, which will eventually become the placenta, and the body of the future man is formed from the embryonic nodule.
After ovulation, a pregnancy test with a determination of the concentration of the hormone hCG within 10 mU / ml (in a non-pregnant woman this hormone varies from 0–5 mU / ml) can be already about 12-14 days,
Comments: September 09, 2007 – 13:44 |
For many women planning a pregnancy, the question arises: when can a pregnancy test be performed to see 2 treasured stripes? Test makers, doctors, and friends are advised not to do tests until the delay. Let’s see why and try to calculate the probability of a positive pregnancy test depending on the DPO (the day after ovulation).
For our calculations, we take as a basis a pregnancy test with a sensitivity of 25 mUI. The test responds to the presence of pregnancy hormone hCG in the blood of a woman. With a sensitivity of 25 mUI, the test is able to show a positive result, if in the urine of a woman the hormone hCG has exceeded this bar,
To better understand how the hormone hCG grows in the first days after implantation, look at the graph (the growth of the hormone hCG is marked with a green line):
Suppose that the implantation occurred on the 7th day after ovulation and we assume that on this day the level of hCG "jumped" up to 2 mUI. The next day, the hCG level doubled to "whole" 4 mUI. At 9 DPO doubling again and 8 mUI. Although the pregnancy has already come, but for the test with sensitivity from 25 mUI, the hormone level is still very low, so the test will still be negative. Only on day 11 after ovulation, the level of hCG crosses the 25 mUI border for the first time and the pregnancy test may for the first time show a weak second strip. In our calculations, we do not take into account the fact that the content of hCG in the urine may be much lower than in the blood and for each woman this level is individual.
Now imagine that the implantation did not occur at the 7th DPO, but only on the 10th (also the norm!). This means that according to our calculations, the first strip can be seen only at 14 DPO. So we got to the definition of the delay and the answer to a frequent question: "After how many days you can do a pregnancy test?". Typically, the length of the second phase is about 14 days and that is why test manufacturers advise to carry out pregnancy tests only after a delay, that is, at the earliest at 15 DPO.
The probability of implantation depending on the DPO
Speaking of the fact that implantation usually occurs on the 7-10 day after ovulation, you need to know that early and late implantation rarely happens. The probability of implantation depending on DPE is presented in the list: