Women do not always wait until the start of the delay in menstruation in order to do a home test and get an answer to an exciting question. Sometimes it is very important to find an answer as early as possible, and here a reasonable question arises - how long does it take for test systems to show positive results?
How test systems work
Any pregnancy test, no matter what modification you choose, no matter how much it costs, works on the same principle for all such devices. Manufacturers apply to the test a special substance with antibodies to hCG. This reagent is capable of reacting with the molecules of this hormonal substance if present in urine. If there is no hCG in the urine or there is too little of it, then the reagent does not react, and the test shows a negative result.
The hormone in question is present in small quantities in all people, but at the same time its amount is so small that the tests, even the most sensitive ones, do not react to it. If a woman conceives a baby, then after successful implantation of the embryo into the endometrial layer of the uterus, the chorionic villi begin to produce large doses of this substance, doubling every two days.
The hormone is essential for the development of the baby. It supports the functionality of the corpus luteum formed on the ovary after ovulation. The corpus luteum provides the body with progesterone. If there is no pregnancy or implantation for some reason did not occur, then hCG does not increase, and the corpus luteum begins to fade about a week before the upcoming menstruation. As soon as the production of progesterone ends with a complete regression of the corpus luteum, the next menstruation begins.
The beginning of the production of hCG is a kind of signal to all systems of the female body that now they have to work in a completely different mode, rebuilding to meet the needs of a new man growing in the womb.
Earliest dates for diagnosis
The level of chorionic hormone in the blood, and a little later in the urine, increases gradually. It is to increase the effectiveness of testing that manufacturers advise to do tests after the next menstruation does not come. By this time, usually under standard conditions, the level of the substance in urine is quite high in all women, and the probability of a test system error becomes minimal. But there is not always the opportunity and enough patience to wait for the start of the delay. When planning to conduct self-diagnosis before the onset of a delay, you should know the average time frame in which all biological and physiological processes occur, which lead to an increase in hCG.
After conception, which usually falls on the period of the ovulation window, which lasts about a day after the release of the egg from the burst follicle, a very important process of exchange of genetic information takes place during the first 12 hours. A new cell with its own DNA is being formed. It equally includes information from the maternal and paternal germ cells. This new cell is called a zygote.
Continuous crushing of the zygote begins. At the same time, it begins to move through the oviduct into the uterine cavity. In the tube where fertilization takes place, there are no conditions for the growth and development of the embryo further, and nature provides for at least three-day migration of a new organism. The villi of the inner part of the fallopian tube move and push the zygote further. Only on the fourth day after fertilization, on average, it enters the uterus.
Important! During these three days in the hormonal background of women who conceived a baby, and women who did not, there is no difference. There is no point in doing tests, they will all be negative.
Once in the uterus, the embryo, which has turned into a morula, and then into a blastocyst, begins to look for a place for implantation. This is not to say that this is some kind of deliberate choice, rather, the embryo attaches itself where it managed to stick randomly. The endometrium under the influence of progesterone becomes thicker, friable. How long the embryo will spend in a state of free swimming is difficult to say. Typically, implantation occurs one week after conception, although earlier and later implantation is likely.
Having adhered to the wall of the uterus, the chorionic villi begin to secrete special substances that literally dissolve the cells of the inner lining of the uterus. Thus, the ovum gets the opportunity to go deeper into the layer, "dig in" in it, as in a hole. The entire implantation process usually takes up to 40 hours. After this time, the chorionic villi connect with the blood vessels of the uterus, and the baby begins to receive nutrition from the mother's blood, and hCG begins to enter the woman's body, doubling every two days.
From the point of view of medicine, it is impossible to feel the onset of pregnancy. The processes are cellular, delicate. But many women note that about a week before menstruation, they felt differently than usual - there was a slight weakness, fatigue, an unusual metallic taste in the mouth appeared, some noted unusual discharge - drops of blood or brown or pink daubs. This phenomenon is called implantation bleeding and occurs in about a third of women.... Experts associate it with a violation of the integrity of endometrial cells, which occurs when the ovum is immersed during implantation.
But even such symptoms are not yet a reason to do a test. Only from this moment does the production of hCG begin and it takes time for enough hormone to accumulate in the urine for recognition by the test system.
If ovulation, implantation occurred within the described average terms without time deviations, then the earliest period when the hormone content exceeds the sensitivity of the reagent on the test will be 5 days before the start of the next menstruation. From that time on, the most sensitive of the existing tests will be able to show a second stripe, albeit weak, but already distinguishable.
Sensitivity and timing
The tests are distinguished by the level of susceptibility. This is called the sensitivity threshold. If you conduct self-diagnostics before the start of the delay, it is better to choose the most sensitive systems, the packaging of which indicates a threshold of 5.5-15 mIU / ml. Such tests can indeed show a second stripe, even a weak one, even five days before the start of the delay. Then the strip will become brighter, because the level of the hormone will rise.
It is better to use diagnostic systems with a base sensitivity of 20 units no earlier than 1-2 days before the delay, and the most common average sensitivity tests with a perception threshold of 25 units - after the start of the delay. If you have already 5-7 days from the start of the delay, then almost any test determines pregnancy.
Remember that when diagnosing before the delay, the test accuracy will not be 99% claimed. For example, 5 days before its start, the accuracy of any test does not exceed 57%, and for 3 days - no more than 79%.
Timing ratio and how to count correctly
Since conception occurs during the period of ovulation, even if the intercourse itself took place earlier, consider the timing for choosing the optimal one to do testing, it is better either from the beginning of the last menstruation, or from ovulation, if you know its day. In the first case, the calculation is carried out in DC - days of the cycle. With a standard cycle of 28 days, ovulation usually occurs on the 14th day of the cycle, and you can find out about pregnancy using the test at the earliest on the 23rd day of the cycle. To find out your own timing, subtract 14 from the duration of your cycle, get the estimated day of ovulation and add 9. If you are counting from ovulation, then do the test no earlier than 9 days after ovulation.
Pregnancy is always measured in obstetric weeks. By the time of ovulation, a woman is already 2 full weeks of pregnancy, because the starting point is the first day of the last menstrual period. When the test shows you the cherished two strips, you will have exactly 3 weeks of pregnancy, but if the delay has already begun, then the test shows pregnancy at 5 weeks. It is not accepted to count the terms from conception, since it is impossible to establish the time of conception. If, again, you understand that this happens during ovulation, then one and a half weeks after this event, you can start doing tests.
A digital test for determining pregnancy with a dual sensor with the function of determining the number of weeks calculates the term by the average amount of hCG and quite often "misses".
Be sure to keep in mind that such a diagnostic system counts the number of weeks not from menstruation, but from conception. To establish the obstetric period, add two weeks to the test.
Useful Tips
There are a few expert tips worth taking into account.
- When doing tests before the delay begins, remember that morning urine is best for self-diagnosis. After awakening, urine is more concentrated and dense, it contains more of all substances. Having received a weak second strip, repeat testing no earlier than two days later. With a normally developing pregnancy, the strip should become brighter.
- If a week before menstruation blood appears in the discharge, monitor your well-being. Implantation bleeding looks like a rather scanty discharge and lasts no more than a day. If the discharge lasts longer, consult a doctor, perhaps it is not implantation at all, but an inflammatory process or hormonal disruption associated with insufficiency of the second phase of the menstrual cycle.
- If the delay begins, and the tests continue to remain negative, a blood test for hCG can be done, and a week after the start of the delay, visit the ultrasound office to determine the reasons for the delay.
Do not chase expensive test systems, according to women's reviews, even the most inexpensive tests can show the second strip at the earliest possible date.
