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Every woman who dreams of having a baby or simply doubts whether she is pregnant or not is in a hurry to find out about the onset of conception. Therefore, many of the fair sex acquire pregnancy tests and conduct them much earlier than the due date. As a result, they get an unreliable result and, after a certain time, they are surprised to learn that the pregnancy has nevertheless come. At the same time, women believe that the test turned out to be faulty, although in fact it was only necessary to calculate the optimal date when to take a pregnancy test after conception.
How exactly does the test determine pregnancy?
Naturally, trying to find out with a pregnancy test the day after intercourse whether conception has occurred is pointless. The reason lies in the peculiarities of the work of all rapid tests.
The simplest pregnancy tests are represented by strips on which there are two indicators. After the test is lowered into the urine to the desired mark, one band becomes visible – it is the control. If after a few minutes a second strip appears, then this indicates conception. It is the second band that contains a special substance that reacts with hCG (human chorionic gonadotropin). This hormone begins to be produced in enhanced volumes after the embryo implants against the wall of the uterus. HCG circulates to a greater extent in the blood, and after a while it begins to accumulate and be excreted in the urine.
It should be understood that this hormone is always present in the female body, but if there is no pregnancy, then its level is very low. The hormone reaches its peak value 2-3 months after conception. However, the test is able to recognize it in the urine much earlier – on average, 15 days after the onset of pregnancy.
After how many days do different types of tests show pregnancy?
There are various types of devices on the modern market, including test strips, tablet tests, inkjet electronic tests.
The optimal days when you can conduct a study to determine pregnancy depend on a number of factors:
Test sensitivity.
Condition of a pregnant woman. For example, with a threatened miscarriage or an ectopic pregnancy, tests may be uninformative for a long time.
Accuracy in following instructions.
Test sensitivity and timing of pregnancy
Tests that have a sensitivity of 10 mIU / ml are able to detect pregnancy already 7-10 days after embryo implantation. Previously, it makes no sense to conduct a study, since there are currently no tests with greater sensitivity on sale. Moreover, before this period, the hCG hormone in the required concentration in the urine simply cannot accumulate. Therefore, it is best to perform a pregnancy test 10 days after a possible conception. This will save money on the purchase of the device and once again not be nervous about the result. As a rule, tests with hypersensitivity will be presented either by electronic or tablet devices.
Tests that have a sensitivity of 15 mIU / ml allow pregnancy to be determined 10 or more days after conception has occurred. These tests most often include inkjet devices that are not equipped with an electronic scoreboard. Although on sale you can also find tablet tests with similar sensitivity to hCG.
Tests with a sensitivity of 20-25 mIU / ml are able to determine pregnancy no earlier than 15 days after fertilization of the egg. Such devices are represented by strip strips. These tests are the most affordable, but at the same time, have the least accuracy. Moreover, it will be the lower the earlier the woman conducts the study.
When to take a pregnancy test after conception to get an accurate result?
A pregnancy test after conception should be done at the time when you can get the most accurate result. Most manufacturers indicate that their testing systems are highly reliable, which is 97-99,8%. Thus, the risk of error is minimal. However, you need to carry out the procedure on certain days. The optimal date is considered to be the date on which menstruation should begin.
If you do the test earlier, then the risk of getting an erroneous result increases significantly:
The reliability of the test is equal to 55% when conducting a study 4 days before the onset of menstruation.
The reliability of the test is equal to 86% when conducting a study 3 days before the onset of menstruation.
The reliability of the test is equal to 97% when conducting a study 2 days before the onset of menstruation.
The reliability of the test is equal to 98% when conducting a study 1 day before the onset of menstruation. Thus, the risk of error at this time is already minimal and does not exceed 2%.
Be sure to take into account the instructions of the test manufacturers that the study should be carried out on the first day of the delay in menstruation, as this guarantees the most reliable result. This statement is true, but you need to know some subtleties. The thesis is based on the fact that a woman’s pregnancy occurs exactly in the middle of the cycle, when ovulation occurred, and menstruation should begin 14 days after the conception occurred. Tests are able to show pregnancy only in the third week of gestation, that is, on the 15-16th day after fertilization. If everything happened exactly according to this scenario, then the result of the study conducted on the first day of the delay in menstruation will be as reliable as possible.
Now about the most important thing – conception does not always occur exactly in the middle of the cycle. Therefore, conducting a study even within the time recommended by the manufacturer may be uninformative. Practicing gynecologists are well aware of this, so they give an unequivocal recommendation – to do a pregnancy test after 1-2 weeks of delayed menstruation. If a woman knows that sexual intercourse, which could lead to conception, occurred exactly closer to the day of ovulation, that is, by the middle of the menstrual cycle, then the test can be performed on the 7th day of the delay in menstruation. When sexual intercourse was closer to the onset of menstruation, and it did not occur, then the most accurate test result can be obtained two weeks after the delay in menstruation. Only in this case can we say that the test was 99,8% reliable.
For many women, this waiting period may seem too long and tedious. In this case, they need to purchase a test that is highly sensitive to hCG and conduct a study 15 days after unprotected sexual contact. At the same time, it is important to know on which day intimacy occurred, which was capable of leading to conception. Using such calculations, you can not take into account the duration of the delay in the next menstruation.
Now on sale there are tests that are highly sensitive to human chorionic gonadotropin. On packages with such products, the number 10 mIU / ml is indicated. These devices allow you to diagnose pregnancy, starting from 7-10 days after intimacy. If just such a test was purchased, then it is necessary to count 7-10 days from the date of unprotected intercourse and conduct a study within these terms. When performing a test on day 7 from a possible conception, you can get a result whose accuracy will be 88%. If the test is performed after 10 days from the date of fertilization, then the risk of error is completely reduced to 1%.
So, it would be more correct to conduct a study not on the first day of a delay in menstruation, but to calculate from the date when unprotected intercourse occurred. In this case, the day of the beginning of the next menstruation does not matter. However, it is important to pay attention to the sensitivity of the device. With the help of conventional tests, it is possible to perform diagnostics after 15 days from the date of the intended conception. Tests with increased sensitivity to hCG allow the procedure to be carried out as early as 7-10 days after possible fertilization.
Why can a test fail?
Sometimes even compliance with all the deadlines and strict adherence to the instructions leads to the fact that the tests give false positive and false negative results.
This happens due to a number of factors, including:
Getting a false negative result:
The concentration of the hormone in the urine did not reach the desired level due to the individual characteristics of the organism.
The woman has severe kidney dysfunction, which prevents the normal excretion of hCG in the urine.
Urine is highly diluted. This is observed when taking diuretics, or in the case when a woman drank a lot of liquid on the eve of the study. Therefore, doctors recommend testing in the morning, immediately after waking up. This is especially true for determining pregnancy in the early stages.
Getting a false positive result:
The woman had an abortion or miscarriage, and no more than 30 days have passed since then.
A woman takes medicines that contain hCG in their composition.
A neoplasm develops in the body that produces chorionic gonadotropin or stimulates its increased production. It can be cystic drift, pituitary tumor, uterine chorionepithelioma, etc.
In other cases, it makes no sense to distrust the results of the testing. Therefore, if pregnancy is detected using a test, it is necessary to seek the advice of a specialist. In the event that the test gives a negative result, and menstruation does not occur even after 10-14 days from the due date, a trip to the gynecologist should be mandatory.