How many days after conception does the test diagnose pregnancy?

Women planning pregnancy are very sensitive to the issues of early diagnosis. Some begin to do home pregnancy tests as early as a couple of days after intercourse, and this becomes a cause for worries, nervous tension. To prevent this, you need to know exactly how many days after conception the tests show correct and reliable results.

What happens after conception?

To talk about how accurate self-diagnosis can be with the help of modern test systems available to everyone, you need to clearly understand what exactly happens in a woman's body after conception, because it is these changes that create the preconditions for the emergence of so-called “interesting position” markers, which and are installed through testing.

It is more correct to count not from the date of unprotected intercourse, but from ovulation. In women, it occurs on average 14 days before the end of the menstrual cycle. With a cycle of 30 days, the release of an egg should be expected on day 16, and with a 28-day cycle - by 14. The fact is that, technically, conception itself is possible only during the ovulatory phase, which is limited by the life of the egg (24-36 hours).

It means that there is no difference when there was sexual intercourse - a few days before ovulation or on the day of ovulation, conception will fall on ovulation (plus a day). Spermatozoa retain morphological and physiological characteristics for up to 3-5 days, and therefore even sexual intercourse, which was 4 days before ovulation, may well become fateful, just the conception itself will take place not on the day of sexual intercourse, but after 4 days.

On the day of ovulation, the mature egg leaves the follicle located on the surface of the gonad (ovary). The follicular bubble bursts. In its place, a temporary gland begins to form, which produces progesterone. It is called the corpus luteum. At the same time, no less important metamorphoses are taking place with the reproductive cells of the parents: they merge, there is an exchange of DNA information (23 chromosomes from each parent form the genome of a new cell - a zygote). The formation of the zygote after the meeting of the sperm and the oocyte takes about 12 hours.

After that, the zygote begins to split, the number of cells inside one increases, and immediately the slow movement of the zygote from the fallopian tube to the uterus begins, since only in the uterine cavity, nature provides the most optimal conditions for the development of offspring. The way to the uterus takes about three days. The motionless zygote is helped in this by contractions of the muscular layer of the fallopian tubes, and the rhythmic, synchronous oscillation of the villi, which in abundance cover the inner part of the oviduct.

The embryo usually appears in the uterine cavity on the 4th day after conception. By this time, it consists of at least 16 cells. Blastomeres have been formed, they are already differentiating into internal and external. The internal ones, when the time comes, will become the basis for the formation of the baby's organs, and the external ones will be the basis of the placenta, fetal membranes. A day later, on the fifth day after conception, the embryo acquires a new status - it becomes a blastocyst, in which there are more than 30 cells.

For another 2-3 days, the embryo is in a free state: it does not attach for anything, and everywhere, if I may say so, leads an autonomous existence. Only 7-9 days after conception, the most important process occurs, after which we can talk about pregnancy as a fait accompli. The embryo is implanted into the wall of the uterus.

The blastocyst sheds the zona, and the ovum adheres to the endometrium. Then the villi of the outer layer begin to produce an enzyme that dissolves endometrial cells. The fertilized egg sinks deeper into the endometrial layer. The villi begin to produce a special hormone - hCG. Chorionic gonadotropin acts as a support for the corpus luteum. In non-pregnant women, 10 days after ovulation, it fades away, regresses.

But if implantation took place, this is a signal that the need for progesterone is high, and the temporary gland continues to exist and supports the embryo with the correct hormonal background. Due to the high level of progesterone, the woman does not start her next period.

All existing pregnancy tests are based on the determination in the urine of traces of the hormone hCG. And until its amount reaches certain values, tests will show nothing.

Terms of determination

As you can see, no significant changes occur in the woman's body, either two or four days after conception, which would be characteristic of pregnancy. The hormonal background before implantation remains the same in both pregnant and non-pregnant women. It is dominated by a natural excess of progesterone levels, and this is typical for all women in the second half of the cycle. And therefore it is not worth looking for symptoms of successful conception in the first week after ovulation - they cannot exist in principle.

Everything that a woman can perceive as signs of pregnancy at this time is nothing more than psychogenic symptoms or far-fetched sensations that have nothing to do with real changes in the body during pregnancy.

Hence the conclusion - the test, even the most accurate and modern, will not show pregnancy in the first week after ovulation (from 14 to 21 days of the cycle). It is possible to find out whether the efforts of partners after unprotected intercourse have been successful only if when the level of human chorionic gonadotropic hormone in the urine of a woman exceeds the sensitivity threshold of the test system.

The level of this hormone increases in leaps and bounds, but evenly. Every two days, the concentration of a substance in a woman's blood doubles with a singleton pregnancy. If there are two embryos, then the excess will go faster - 4 times every two days. First, the level of hCG rises in the blood, and only after a few days - in the urine. Thus, with the help of a home test, a clear, reliable result can be obtained only a week after implantation, that is, 6-7 days after implantation.

Typically, this is the first day of your missed period. Therefore, test makers and it is recommended to start testing no earlier than the start of the delay... If you use the test earlier, there is a high probability of getting a false negative result (the test will show one strip, despite the fact that conception took place). Modern test systems are different: strips, inkjet, digital, tablet. But they all work according to the same principle: if the level of hCG in the urine is above the sensitivity threshold, the reagent applied to the test zone shows a second strip.

But tests have different threshold of sensitivity. This means that ultrasensitive systems (on the packaging of these it is indicated that the threshold is from 10 to 15 units per milliliter of liquid) show a positive result with a lower concentration of the desired substance in the urine. In this way, ultrasensitive systems can be used not from the first day of delay in menstruation, but earlier - they can be done 2-3 days before the start of the delay. The overwhelming majority of tests that are on the market today have a sensitivity of 20-30 units. They determine the "interesting position" a little later, and are more suitable for use after the onset of a missed period.

Again, one cannot but foresee possible non-standard situations. If ovulation occurred later than the expected day, then the implantation process will be later, which means that the hCG level will begin to rise later. If ovulation happened earlier, then the amount of chorionic gonadotropin may rise earlier than the indicated average dates.

Stress, diseases, hormonal shifts, and chronic fatigue can affect the timing of ovulation. And this is another reason why it is recommended to do tests from a period at which both with timely and late ovulation, the level of the hormone is already increased - this is the time after the start of the delay.

Summarizing all of the above, we note:

it is possible to determine pregnancy with a home test with high accuracy from the moment of the first day of delay in menstruation and later;
on ultrasensitive tests, the second strip appears earlier - 12-13 days after ovulation (conception);
days should be counted not after sex, but from the beginning of the cycle (from the first day of menstruation) or from the day of ovulation (as the most likely day of conception);
the best time to check if you are pregnant with tests with an average sensitivity (from 20 units and above) is at least 2 weeks after the intended conception (or 14 days after ovulation).

Can I find out earlier?

If it is fundamental for a woman to determine pregnancy before the delay in menstruation begins, then it is worth contacting a doctor. Given that, first of all, the hCG hormone rises in the blood, a blood test for hCG will be more accurate and effective. It can be done on a paid basis in any clinic - the research costs from 300 to 600 rubles, depending on the clinic and the region. For the study, a woman's venous blood is needed, taken on an empty stomach in the morning. Results can be obtained the same day or the next.

The great advantage of analysis is that you can get a positive result as early as 10 days after ovulation (24 days of the cycle). The laboratory assistant diagnoses the level of hCG, which the pregnancy tests are unable to detect, because the determination takes place in a clear and specific quantitative form.

Laboratory diagnostics will also be of great help if a woman received a dubious test result - a weak second strip or a negative home test result after a positive one. In any doubtful situations, determining the level of hCG in the blood helps to put everything in place.

In the case of laboratory diagnostics, it is also necessary to adhere to reasonable time frames. It is not worth checking the amount of the hCG hormone in the blood plasma 2 or 3 days after conception, and even 4, 5 or 6 days after ovulation it is too early to donate blood, because before the moment of implantation, there is no point in analyzes and testing at all - hCG does not rise yet.

The earliest period at which an increase in the level of the hormone can be detected is the period 9-10 days after ovulation. If you then repeat the analysis (find out the concentration of hCG after 11, 14 days), then you can pay attention to high growth rates - this means that the pregnancy is developing normally. A slow increase in hCG over time may indicate an ectopic pregnancy, hormonal deficiency of progesterone and the associated threat of miscarriage at an early stage. If the hCG in the blood stops and begins to decline, a frozen pregnancy is possible, in which the fetus stopped developing and died.

How to get an accurate result?

A woman who does a test at home (before or after a delay) should remember that even the simplest test at first glance requires a correct approach to its use, otherwise one should not count on reliable results. First of all, you should correctly approach the choice of the test. Buy the system only at the pharmacy, because at the supermarket checkout, storage conditions may be violated, and an expired test or one that was stored in high humidity conditions may turn out to be faulty and unusable. The dough packaging should not be wrinkled, not torn, not broken. Be sure to check the expiration date.

Before testing carefully read the instructions. For strip strips, it is very important not to overexpose the test in liquid and not to immerse it deeper than the MAX line. Waiting for the result should also not be protracted - usually manufacturers recommend evaluating the result after 5-10 minutes, and this is not just that: as it dries, a second gray strip may appear on a negative test, which is a dried reagent, she does not speak about pregnancy, but can mislead a woman.

When conducting innovative e-tests, remember that it is important not to allow urine to spill onto the case, and during cassette testing, do not drip too much liquid into the urine opening.

Use a clean, dry container to collect urine.

It is best to do a test for early diagnosis on morning urine - after a night's sleep, urine is more dense in content of substances, concentrated. After a delay (after 5,6,9 days) there is no longer a difference at what time to do the test: the level of hCG, even if conception occurred before menstruation, a few days before, will already be sufficient to determine it in the urine of any daily portion.

Before testing, it is advisable not to drink or consume large quantities of foods with a liquid content for at least 4 hours. This is true if the diagnosis is not carried out in the morning.

The home test results are pretty easy to understand. A positive result is two bright stripes of the same color saturation. A weakly positive result is one more faded line with a bright control. In this case, it can be assumed that the test was done too early, you need to repeat the diagnosis every other day, on the morning urine sample. If the strip does not become brighter, blood should be donated for hCG, an ectopic pregnancy or the risk of early miscarriage is not excluded.

A negative result is the presence of only one control strip. It appears on a healthy test, suitable for use in contact with any liquid. And the absence of stripes generally indicates that the test is faulty, unusable. Replace it with another one and repeat the diagnosis in compliance with all the rules and requirements of the instructions.

Reviews

According to women, many tests showed positive or slightly positive results two days before the expected menstruation. Many indicate that before the delay, the tests were not carried out simply because there was no thought of pregnancy, and only after there was no menstrual bleeding for several days, the first test was done and immediately received a bright positive result, which is beyond doubt.

The price does not matter, women say. The cheapest test strips are sometimes much more accurate than the expensive test systems.