Learning to apply a pregnancy test before the delay
There is hardly any woman in the world who does not want to know about the pregnancy as early as possible. The first physiological signs of a delicate situation, such as morning sickness, frequent urination, increase and soreness of the mammary glands, are rather subjective and appear after the delay of menstruation.
Ultrasound examination of the uterine cavity will also show a pregnancy for at least five weeks. That is why scientists have set themselves the task of developing a pregnancy test before the delay of menstruation. And modern technology has allowed them to successfully solve this issue.
The pregnancy test before the delay for home use is based on a qualitative definition of the level of human chorionic gonadotropin( hCG) in a woman's urine. HCG is a special hormone that begins to be produced by the embryo immediately after the implant is implanted into the uterine wall.
Below are the norms of the content of HCG in the serum( in mIU / ml) in women:
- no pregnancy( 0-5)
- pregnancy in question( 5 -25)
- 1-2 weeks( 25-156)
- 2-3 weeks(101-4870)
- 3-4 weeks( 1110-31500)
- 4-5 weeks( 2560-82300)
- 5-6 weeks( 23100-151000)
- 6-7 weeks( 27300-233000)
- 7-11 weeks(20900-291000)
- 11-16 weeks( 6140-103000)
- 16-21 weeks( 4720-80100)
- 21-39 weeks( 2700-78100)
It should be clarified that these standards are approximate and depend on the specific laboratory in question.which is being analyzed. In addition, the concentration of hCG in urine is usually slightly less than in the blood.
Most home tests allow you to "catch" hCG, whose content in the urine exceeds 25 mIU / ml. Although more highly sensitive tests with a threshold of 20 mIU / ml and even 10 mIU / ml are also sold.
test There are several varieties of home tests for pregnancy detection. Most of them operate according to the same principle. Only the way of carrying out the diagnosis differs and the variant of displaying the result.
So, there are jet tests, which you just need to substitute for a stream of urine. There are tests in the form of a cassette, on which you need to drop a few drops of urine from a special pipette. Typically, these cassettes are highly sensitive. The most common and cheap are the tests in the form of strips. They need to be lowered to a special mark in a small container with urine and hold for 15-30 seconds.
Most often, the presence of pregnancy can be judged by the appearance of a second strip. At the same time, its brightness does not matter. The first strip is the control and indicates that the test is not spoiled. Sometimes, instead of two strips, you can see a plus sign. This result also indicates the presence of pregnancy( respectively, minus indicates its absence).
Digital tests have become increasingly popular. The result of the diagnostic performed with this test is very easy to interpret. The electronic display will highlight not only the message that you will soon become a mother, but also the estimated period from the date of conception.
When to apply the pregnancy test
So, we turn to the most exciting question for most women: how many days before the delay can you confirm the pregnancy? Usually implantation of the embryo into the uterine cavity takes place 7-10 days after ovulation( DPO), but early or late implantation is possible. Below we see how the probability of implantation from DPO depends:
- 3-5 DPO - 0.68%
- 6 DPO - 1.39%
- 7 DPO - 5.56%
- 8 DPO - 18.06%
- 9 DPO - 36.81%
- 10 DPO - 27.78%
- 11DPO - 6.94%
- 12 DPO - 2.78%
Immediately after the fertilized egg is introduced into the uterine wall, a hCG hormone appears in the blood of the uterus( and a little later in the urine), the level of which doubles approximately every two days. So, if the implantation occurred at 7 DPO, the HCG content in the blood will be approximately 2-4 mIU / ml. At 9 DPO, the hCG level will reach 8 mIU / ml. And only at 11 DPO the concentration of hCG in the blood will be 16 mIU / ml, and the earliest pregnancy test will show a positive result.
And imagine, if the implantation happened on the 10th day? That's why doctors are not advised to do a pregnancy test before menstruation and are encouraged to wait at least the first day of delay.
When do: morning or evening?
Most manufacturers recommend early diagnosis using the first portion of urine. But practice shows that it is enough not to take a lot of fluids and not go to the toilet for several hours.
These recommendations are for those cases where you are conducting a pregnancy test before the delay. If the delay has already come, and you suspect that you are pregnant, then safely perform the diagnosis without waiting for the morning. Most likely, the concentration of the hormone hCG in the urine has already crossed the threshold of sensitivity, and you will see the long-awaited second strip.