If the question arises about a possible pregnancy, the first thing any woman does today is to go to the pharmacy for a pregnancy test.
These miniature diagnostic systems for home use are affordable and convenient and should be used by any sexually active woman of childbearing age.
The first question that arises when you suspect a possible conception is when you need to do a pregnancy test, how long should you wait?
Modern pregnancy tests are highly sensitive and capable of detecting pregnancy as early as possible, sometimes even before menstruation is delayed.
But it is worth remembering that the tests are not omnipotent and they will not show pregnancy the very next day after the "dangerous" intercourse. This is due to the peculiarities of the conception process and the mechanisms of the tests.
How the test works
To understand how long it takes to take a pregnancy test, it is important to remember that ovulation occurs approximately in the middle of the cycle, and conception occurs within a few days after the release of the egg.
At the same time, after the egg is fertilized, a gradual progressive increase in the level of the hormone in the blood occurs.
As its concentration increases, by the time of implantation of a fertilized egg into the wall of the uterus, about 7-10 days, the level of hCG also increases in the urine. In this case, the level of hCG doubles approximately every day.
Thus, the test can show the presence of pregnancy after about 14 days or more, just in time for how menstruation should begin.
There are also more sensitive tests that can show the presence of pregnancy a few days before the delay (usually no more than 2-3 days), they have a sensitivity of 5-10 mIU / ml and are usually inkjet tests.
However, it is always worth remembering that women with an unstable cycle can ovulate early or late, and conception can occur with deviations from the average. Therefore, it is difficult to answer exactly how long it takes to do a pregnancy test, wait until your period is delayed.
The instructions often indicate that for the study it is worth using the morning portion of urine immediately after waking up, but why should a pregnancy test be done in the morning?
The fact is that morning urine contains in the early stages the maximum amount of the hCG hormone and will show more accurate results than at other times of the day.
But if you use a test with high sensitivity, from 5-10 mIU / ml, then the time of the test is not important - in the presence of pregnancy and delay, the test will show a positive result.
How to evaluate the result?
If you have done a pregnancy test, it is important to correctly assess its result, especially if it is an early period - before the delay or its first days.
By the way, it is for the reliability of the result that it is recommended to carry out a pregnancy test in the morning. This will avoid false negative results.
If the test shows two stripes, it is highly likely that you are pregnant if unprotected intercourse has taken place during this menstrual cycle.
But it is worth remembering that the result can be influenced by hormonal changes, the presence of pathologies with the release of the hCG hormone without pregnancy. And if the test is carried out too early, even if there is a pregnancy, it may show one strip.
And then the question arises - how many times do you need to do a pregnancy test. Usually, with a positive pregnancy test, one study is enough, the next step should be a visit to the doctor and an ultrasound scan.
If the result is negative, it is worth waiting two to three days in order for the concentration of the hCG hormone to increase (remember about late ovulation), and repeat the test.
If you have a delay in menstruation, and the pregnancy test is negative, do it again after a few days, perhaps its sensitivity is not great.
If, after that, the test does not become positive, you need to consult a doctor and find out the reasons for the delay - the tests are also sometimes wrong.
If you are planning a child and are looking forward to good news, or you are afraid of such a prospect, and you need to know information about whether conception took place or not, they will come to the rescue pregnancy tests.
This simple yet effective home diagnostic tool can be purchased at any pharmacy or 24-hour supermarket, making pregnancy determination process simple and accessible to every woman. It does not require extra costs. But most tests say that they need to be done when menstruation is delayed. Doctors-gynecologists almost unanimously recommend the same.
And how are things really? On what day after conception can the test determine pregnancy? We will talk about this in this article.
Let's first deal with the question of how pharmacy pregnancy tests.
Regular test strips, inkjet tests and test cassettes, as well as electronic tests work on the same principle - in them contains a reagent, which reacts to a special hormone produced in pregnant women: human chorionic gonadotropin, aka hCG. And, although the tests themselves vary in price and type, they all contain a strip soaked in reagent (or two strips, as is the case with regular test strips) inside.
When soaked in morning urine, the test collects the required amount, and then a reaction occurs.
First, a control strip appears - it shows that the test works in principle, and not is overdue(and this happens if the terms and rules of storage are not observed). Further, within a few minutes a second strip should appear on the test - if there is a pregnancy (a "plus" or "minus" sign appears on the digital test). Inside the electronic test there are two strips impregnated with a supersensitive reagent capable of trapping even the smallest concentration hormone in the urine.
In the body of a non-pregnant woman hCG concentration extremely insignificant. And the test is simply unable to catch it. After conception, within a week (it usually takes 1 to 5 days for a fertilized egg to move through the tubes) occurs attachment of the ovum to the wall of the uterus. And it is from this moment that the pregnancy hormone, hCG, begins to be produced in the woman's blood. Its level in the blood increases several times every day, the concentration of the hormone in the urine is two times lower. In some women, the doubling of the hormone occurs more than once a day, but a little less often, once every 36-48 hours.
By the day of the expected delay, the concentration of the hormone in the urine reaches such a level that any pharmacy pregnancy test can "catch" it. But what about those who cannot or do not want to wait for this day? What day after ovulation and the estimated day of conception testing can be done?
This is where ultrasensitive tests come to the rescue of a woman.
What tests can I do before the delay?
Pregnancy tests differ not only in the form of execution, but also in content. In this case, we are talking about test sensitivity... They fall into two categories: ultrasensitive tests and conventional tests. The higher the sensitivity of the test, the less hormone He is able to "determine" hCG by providing the correct test results.
Pregnancy tests are four types of sensitivity:
- tests with a sensitivity of 10 mU / ml;
- tests with a sensitivity of 15 mU / ml;
- tests with a sensitivity of 20 mU / ml;
- tests with a sensitivity of 25 mU / ml.
The higher the numerical value of the sensitivity, the more hCG in the urine is required for the test to determine pregnancy. The first two tests above refer to categories of ultrasensitive, the last two are usual. The sensitivity of the test is indicated on its packaging.
The best tests with high sensitivity are Frautest (10 mU / ml), Be Sure!, Eva-test, Ultra and Femitest. All of the above tests can be used before the delay of menstruation.
Another excellent pregnancy test, which is able to determine it 10-14 days after ovulation, is the electronic test Clearblue digital... Despite the fact that the manufacturer indicates the sensitivity of the test is 25 mU / ml, this test detects even a small concentration of the hCG hormone, and shows pregnancy earlier than other counterparts - both conventional and ultrasensitive.
The advantage of this test is unambiguously the fact that it does not show the so-called “ ghost stripes"- when at an early stage the test shows a very pale, barely noticeable second strip. Clearblue test results are displayed as plus or minus, eliminating misinterpretations. It also displays the gestational age in weeks.
In order for the test to show an accurate result, you need to know two things: when exactly conception took place, and how many days a woman's menstrual cycle lasts. Based on this data, you can calculate the day on which the test is already will show the result.
A woman's standard menstrual cycle is 28 days... It is considered from the first day of the last menstruation. Ovulation - the process of maturation and release of an egg from the ovary, occurs on 12-14 day of the cycle... Within 48 hours from this moment, the egg is ready for fertilization, and if there was sexual intercourse on these days, conception occurs. If it was not there, the egg dies, and together with the epithelium it leaves during menstrual bleeding.
But not all women have a standard menstrual cycle. For some, its duration changes. every month- in one it can be 25 days, in another - 32 days. This cycle is called irregular. And this usually presents difficulties in the calculation. ovulation dates.
With a lengthened menstrual cycle, ovulation usually occurs at 15-17 day... When shortened (up to 28 days) - by 10-12 days. Keeping a chart of your menstrual cycle can help you navigate when you should. ovulation occurs.
If you planned a baby in advance, and tracked your ovulation using the basal temperature measurement method, ultrasound of the follicles or test strips created to determine the date of ovulation, then the date of the expected conception should be known for sure.
Now let's move on to the calculations using the example of a standard cycle of 28 days. If ovulation was on the 12th day of the cycle, sexual intercourse took place on the 13th and 14th day of the cycle, then fertilization should have occurred on day 14(deadline). From that moment on, for 5-7 days, the egg moved through the tubes towards the uterus, where it was supposed to occur its attachment... It turns out that it took place on the 19-20 day of the cycle.
From this moment, the woman's body begins to produce chorionic gonadotropin, the concentration of which doubles every day. After 2-3 days from the moment the embryo is attached to the uterus, the level of hCG will suffice in order to be able to catch the hypersensitive tests.
It turns out that a pregnancy test can be done on 23-24 day of the cycle- 5 days before the onset of the delay. With a longer cycle - 27-29 days. With a shorter (24-26 days - 19-21 days.
It's time to return to the conversation about the so-called " ghost stripes". The fact is that when tested at an early stage of pregnancy, ordinary test strips often show exactly the "ghost strip" - very weak and pale second pink stripe.
Often women are embarrassed by this and make them very nervous, because it is not clear whether this is pregnancy, or whether the reagent has manifested itself.
Let's try to figure it out. Why is the second strip at an early date sometimes so pale? It depends on the concentration of the hCG level in the woman's urine. The higher it is, the brighter the strip. Oversensitive tests are more likely to show a pale second streak. And, as the manufacturers assure, it is considered a sign of pregnancy.
Gynecologists confirm this fact and recommend retesting. Normally, as pregnancy develops, tests will show a brighter second strip every day until it becomes equal in color. with control... This usually occurs on the first day of your missed period.
If a woman drinks a lot of fluids, or she has kidney problems, then the strip may remain dim for a long time. Unfortunately, with an ectopic pregnancy tests also show a very faint second band, therefore, if you have such a situation, it is recommended to consult a doctor as soon as possible and conduct a full-fledged ultrasound examination.
How do I distinguish a faint second line from a reagent? Usually the reagent appears as thin strip not pink, but gray or light gray. The second strip during pregnancy, even pale, has distinct pink tint and wider.
The easiest way to check if it is a reagent or a desired pregnancy is to buy several tests from different manufacturers. If in doubt, do two tests of different brands contract. If both show a faint but distinct second streak, you are pregnant.
After that, it is advisable to repeat the testing with a break of one day. If the second strip becomes brighter, congratulations can be accepted with confidence. If you still have any doubts, the easiest way to dispel them is to hand over hCG blood test... In the blood, this hormone is contained in a higher concentration, and is able to diagnose the fact of conception 8-10 days after ovulation.
A pregnancy test is an easy way to determine whether you are pregnant today. With its help, you can find out about the onset of pregnancy even before the start of the delay, because today tests with varying degrees of sensitivity are offered. To obtain a reliable result, you need to understand all the intricacies of home express diagnostics of pregnancy.
What is a pregnancy test?
A few weeks after conception, the body begins to secrete a hormone - chorionic gonadotropin or hCG. This happens after the embryo is attached to the uterus. With each subsequent day, the content of hCG in the blood and urine increases, reaching a maximum by 8-9 weeks.
Sensitivity to this hormone is the basis for determining pregnancy using a test. Its onset is signaled by two strips impregnated with a special substance. One of them turns bright red after contact with any liquid, and the second only when immersed in urine, which contains a certain level of hCG.
The likelihood of a correct result
The accuracy of the information received when using the pregnancy test is 97.5%. In this case, the result is influenced by compliance with the instructions for its use and adherence to certain rules.
When can I do a pregnancy test?
As a rule, the manufacturers of pregnancy tests recommend that they be carried out no earlier than the first day of the delay. This is due to the fact that hCG is not yet detected in the urine before. With a regular menstrual cycle, a mature egg is released in the middle of the cycle. If the cycle is 30 days, then it will be 15 days. Fertilization occurs only within the next two days. The oocyte, which fused with the sperm, moves for another 5 days to the place of attachment in the uterus.
Therefore, hCG will begin to be released at about 22 days of the cycle, and at first in a small amount. At this time, only a blood test can determine its presence. In urine, it will begin to come to light a little later. With an irregular cycle, a woman herself can determine the day of ovulation using special tests and measurements. Another 12 is added to this day, and then you can take a blood test for the level of hCG, and in the urine it will begin to determine approximately 15 days after the expected ovulation.
Types of pregnancy tests
In pharmacies, you can find a wide range of pregnancy tests, differing in price and in the declared level of sensitivity. Each manufacturer promises the most accurate result, so you need to figure out how they differ from each other:
Strip test or a paper strip known to many, on which there is a layer with antibodies to hCG. They react with a hormone in the urine to produce a second streak. Such tests are the most popular and are distinguished by their low cost. But they make mistakes more often than other types, are not very convenient to use, and also show pregnancy only after a delay. To diagnose pregnancy with a strip test, you need to take a clean container and draw a small amount of urine into it. The tip of the dough is lowered there to the indicated level, kept for 10 seconds. The result becomes noticeable in the interval from 3 to 10 minutes. In this case, the second strip will appear the faster, the higher the concentration of hCG in the urine.
Inkjet pregnancy test Convenient in that you do not need to collect urine in a container to carry it out. It should only be placed under the stream of urine, which is convenient when used outside the home. The tip with the filter is under the stream for 10 seconds, and the result will be noticeable within 1-10 minutes. Such tests are expensive, but they are accurate and easy to use.
Tablet test is a box with two windows. In principle, it is similar to a strip test, but it is considered more reliable and, accordingly, higher in price. It comes with a pipette and a container for collecting urine. A little urine is dropped into one window from a pipette, and the result is displayed in the second. You can evaluate it within 10 minutes.
Electronic or digital test for pregnancy is by far the most modern. The tip of the filter dough is placed in the urine and you need to wait until it is soaked. The result is evaluated after 3 minutes. In this case, the window will display "+" or the inscription "pregnansy". Electronic tests are considered the most sensitive and also the most expensive. Manufacturers even create reusable models.
Pregnancy test before delay
Today, hypersensitive tests can be found in pharmacies. They show pregnancy even before the delay occurs. They indicate a sensitivity level of 25 mUI, indicating the corresponding hCG content in the urine, at which the second strip appears. Such tests can be done up to 4 days before the delay. If a lower sensitivity level is specified, it is impractical to carry it out before the delay.
How to do a pregnancy test?
Before using a pregnancy test, you must carefully study the instructions, as it differs depending on its type. For the result to be reliable, you need to adhere to the following rules:
- The tests usually do not indicate the time of its carrying out, but gynecologists recommend doing it in the morning after waking up: in the night urine the highest concentration of the hormone hCG, and in the early stages only at this time of day the result can be noticeable.
- The information content can be affected by the intake of diuretics, as well as the large volume of fluid consumed.
- If, after a delay, the test does not show pregnancy, and menstruation does not occur, it should be repeated after a few days. This is especially true for women with irregular cycles.
- The cheaper the test, the lower the cost of the reagent used in it, therefore, the higher the probability of error.
- The most common test strips are those that should be dipped in a container of urine. It is important here that the test is placed only up to the specified level, kept for no more than the recommended time, and the result is evaluated after the time allotted in the instructions. This will help reduce the likelihood of an incorrect result.
- The test result is described in the instructions for it. One strip is colored in any case, since it is a control, and the second only when pregnancy occurs, that is, for a positive result, 2 bright red stripes should appear.
Why is there a weak second strip on the test?
If there is a second strip on the test, but it is poorly expressed, this may indicate a low concentration of hCG in the urine. The reasons can be:
- threat of interruption;
- short pregnancy period;
- ectopic or undeveloped pregnancy.
Such a result equates to a positive, but it is best to do a control test after a few days.
Sometimes a weakly expressed second strip may indicate a false positive result.
False positive pregnancy test - how to understand?
It happens that a woman strictly follows the instructions, but the test shows the wrong result. Reasons for a false positive test:
- Ovarian dysfunction.
- Taking medicines with hCG prescribed for infertility.
- Use within two months after an abortion or miscarriage.
- Vesicular motility and chorionic carcinoma, related to hormone-producing tumors.
- The expiration date of the test.
Can the test not show pregnancy?
Reasons that home express diagnostics does not show the second strip when pregnancy occurs:
- too short term;
- threat of interruption;
- ectopic or undeveloped pregnancy;
- endocrine dysfunction;
- non-compliance with the instructions for using the test;
- kidney disease;
- stale or collected urine during the day;
- a large amount of liquid drunk, leading to a low concentration of hCG.
Can a pregnancy test be done in the evening?
You can carry out a pregnancy test at any time of the day, but the reliability of the result still depends on this: as mentioned above, the highest concentration of hCG in the body of a pregnant woman is observed precisely in the morning after waking up. Therefore, when carrying out diagnostics in the evening, you can get a false negative result.
This is especially often observed up to two weeks after conception, when the hCG level has not yet reached the value necessary for diagnosis. But at the same time, its concentration in the urine accumulated overnight is such that the test determines its presence. In the future, with an increase in the level of the hormone, it will be detected by the test at any time of the day.
Can the test identify an ectopic pregnancy?
In an ectopic pregnancy, the ovum is attached more often to the fallopian tube instead of the uterus. But at the same time, the hCG hormone is produced. A feature in this case is that it grows very slowly or does not increase at all over time.
The test will show a positive result after the delay, but the second strip is likely to show poorly. Only a gynecologist can diagnose an ectopic pregnancy.
Today you can buy express pregnancy tests in every pharmacy, and even at the supermarket checkout. They are easy to use and reliable: doctors estimate their accuracy at 99% Pregnancy Tests... But often such tests lie.
How pregnancy tests work
Absolutely all pregnancy tests check if there is a special hormone in the urine or blood (if we are talking about a laboratory test) Pregnancy Tests- human chorionic gonadotropin, abbreviated as hCG. It begins to be produced as soon as the fertilized egg attaches to the wall of the uterus.
If there is no pregnancy, hCG has nowhere to come from. If it is, hCG will be required.
Usually, the egg is attached to the uterus six days after fertilization. It is pointless to do the test during this period: it will not show anything. But then the level of hCG increases rapidly, doubling every 2-3 days.
When to take a pregnancy test
Already 8 days after, during which the egg meets its sperm, the level of hCG becomes sufficient so that the pregnancy can be recorded using a laboratory blood test.
A few days later - that is, on the 10-12th day after fertilization - the usual pharmacy tests will also see pregnancy.
Although the instructions for many of them promise an accurate result already on the first day of the delay, doctors advise not to rush Home pregnancy tests: Can you trust the results?... The reason is simple.
If you ovulate on the 10-14th day of the cycle, then by the beginning of the next cycle, at least 13 days will pass from the moment of fertilization. This means that the test will beep to you with two strips.
However, ovulation can shift. If the release of the egg took place on the 22nd day of the cycle, then by the beginning the actual gestational age may be less than 7 days. This means that even perfect tests will most likely not fix anything.
If your cycle is longer or less than 28 days, it is even more confusing.
Therefore, in order to get the most accurate result, it is worth waiting 5-7 days from the start of the delay.
If you are pregnant, the level of hCG by this time will in any case be such that even the cheapest tests with low sensitivity will unequivocally recognize it.
But even if you meet all the deadlines, the test can still mislead you. For example, he will not see a high level of hCG and show a negative result with an existing pregnancy, or, on the contrary, will give out two strips, although it does not smell like pregnancy. To be fair, let's say that this is not so much the fault of the test as you are. Five reasons for false-positive pregnancy tests.
Why rapid pregnancy tests lie
1. You used an expired or damaged test
Rapid tests contain special highly sensitive substances that react to the level of hCG. It is they who, upon contact with the urine of a pregnant woman, are painted in a bright second strip or plus sign.
But if the test is expired or stored improperly, the sensitivity of these substances may decrease. As a result, they will give a negative result, which may turn out to be false.
What to do
Buy tests only at pharmacies, where, unlike supermarkets, they try to ensure the correct storage conditions. When buying, be sure to check the expiration date.
2. You bought a test with low sensitivity
The sensitivity of express tests is indicated by numbers - 10, 20, 25, 30. These numbers indicate the concentration of hCG in urine (in mIU / ml), which they are able to capture. The higher the number, the less accurate the test. The most expensive and accurate options have a sensitivity of 10. But the cheapest ones may not catch hCG and deceive you by showing a negative result.
What to do
When buying a test, be sure to check with the pharmacist how sensitive it is. Also, this information can often be found on the packaging and always in the instructions.
3. You did the test this afternoon
It is not for nothing that the manufacturer speaks of morning urine in the instructions for the absolute majority of tests. It is more concentrated, there is more chorionic gonadotropin in it, which means that the test will be more reliable.
In the afternoon, the hCG content in the urine is lower.
What to do
Use the test exclusively in the morning, as instructed by the manufacturer.
4. You drank a lot of water before taking the test.
Water dilutes the urine, which lowers hCG levels. The rapid test may not sense the hormone and give a false negative result.
What to do
Try not to eat or drink anything before the test.
5. You did not look at the results in time
The instructions for each test specify the rules for its use. For example, like this: "The result can be assessed in 4-5 minutes after the test, but no later than 15 minutes." These minutes are not taken from the ceiling.
The lower limit indicates the time it takes for the test for the sensitive substances contained in it to react to the hCG level. If you look at the test before the agreed date, the second strip (or the plus sign in the corresponding window) may not yet appear and you will see a false negative result.
If you look at the strip after the time indicated as the upper limit, you run the risk of getting a false positive result. Evaporated urine can leave a line that can be easily confused with a second strip.
What to do
Before using the test, read the instructions and strictly follow them.
6. You are taking certain medications
Some diuretics and antihistamines affect the composition of the urine by diluting it. This lowers the level of hCG, which means there is a risk of getting a false negative result.
Other drugs, on the other hand, can give you two strips, although in fact they don't. These medications include:
- some tranquilizers and sleeping pills;
- anticonvulsants;
- fertility drugs.
What to do
If you are taking any of the medicines on this list, you should not rely on the rapid test paper. To determine if you are pregnant or not pregnant, have a blood lab test done.
7. You are sick
If your urine has high blood or protein levels, this can also affect your rapid test result. But here it is important to note that such a situation in itself is extremely unhealthy. Blood in the urine indicates the functioning of the bladder or kidneys, high protein indicates internal inflammation.
Therefore, it is likely that fever and / or discomfort in the genital area and kidneys will be attached to the erroneous two stripes on the test.
What to do
Do not rely on a rapid test if you have a fever and lower back and lower abdominal pain. With such ailments, it is necessary to consult a therapist, gynecologist or urologist as soon as possible so as not to miss a serious illness.
8. You develop an ovarian tumor
Certain types of tumors can trick the test into showing two stripes.
What to do
After receiving a positive result, do not delay the visit to the gynecologist. The physician will conduct research, during which he will establish the actual gestational age (if any), or he will send you for additional tests and to specialized specialists.
How to do a pregnancy test correctly
- Read the instructions. And follow it, of course!
- Remember the rule: if you are healthy and the test is positive, the chance of pregnancy is 99%. A negative result can be false for up to a week after the delay.
- Choose tests with a high sensitivity level. 10 is ideal.
- Do the test in the morning, not in the afternoon and even more so not in the evening.
- Try not to drink at least an hour before the test.
- Do not rely on the test if you are taking the medications listed above or if you are concerned about fever and lower abdominal pain.
- Buy two tests at once to be able to double-check the result.
- If the rapid tests contradict each other, you shouldn't wonder what this is. Do a laboratory blood test to get a reliable result.
Important! A positive test, even if you've been waiting for it for a long time, is, alas, not a reason to rejoice. An increased level of hCG in the urine can be recorded, including with an ectopic or frozen pregnancy. Therefore, having received two strips, go to the gynecologist as soon as possible.