The test for pregnancy is an immediate way to know if a woman is pregnant and is available at any pharmacy, drugstore, supermarket or online.
It is designed to determine whether urine or blood contains a hormone called human chorionic gonadotropin (beta-hCG).
This hormone is produced immediately after fertilization and implantation of the egg into the woman’s uterus.
Beta-hCG stimulates the corpus luteum (corpus luteum) to release the hormone progesterone (Csapo et al. – 1973), which is required for pregnancy (Rothchild – 1983).
If the woman is pregnant, gonadotropin levels grow rapidly, doubling every two or three days.
The normal values of the hCG concentration are between 0 and 5 mIU/ml. In the first week of pregnancy they are between 12 and 77 mIU/ml, then they continue to rise.
One must not assume pregnancy just because a few symptoms are recognizable.
Conversely, minor blood loss may be menstruation or implantation bleeding.
Contraceptive methods such as the pill or the condom do not offer 100% safety, so the woman can take the test to be reassured.
When does the fertilization of the egg take place?
In order to be fertilized, the ovary must release an egg (ovulation).
Usually, ovulation occurs about 14 days after the first day of the last menstrual cycle.
An egg survives about 12-24 hours after ovulation. In order to become pregnant, the sperm must fertilize the egg during this time.
Sperm can survive in the woman’s body for up to seven days. This means that sexual intercourse up to seven days before or during ovulation can lead to pregnancy.
For a greater chance of getting pregnant, one should have sexual intercourse every two or three days throughout the month.
It is not necessary for these days to coincide with ovulation.
About seven days after fertilization, the
pregnancy test is reliable even during lactation, and the woman can become pregnant.
When should a pregnancy test be performed? The right time
Some home pregnancy tests are more sensitive than others.
The more sensitive tests are able to indicate low gonadotropin levels even four days before ovulation is completed or a week after sexual intercourse.
However, a pregnancy test the day after a risky sexual intercourse is of no use.
The sensitivity of a pregnancy test is described on the packaging in mIU/ml (international milli-units per millilitre).
The sensitivity of the pregnancy test ranges from 10 mIU/ml to 40 mIU/ml. The lower the number, the more sensitive the test is and the sooner pregnancy can be detected.
If the test is done too early (even if it is sensitive), the increase in urinary hCG cannot be detected.
Most home pregnancy tests give an accurate result the moment the menstrual cycle should begin, about two weeks after ovulation.
If the test result is negative, but menstruation does not start, the test should be repeated after three days.
If there is a pregnancy, the hormone levels can be detected by the test.
Blood tests carried out in the hospital can also detect hCG.
The blood test is much more sensitive than the urine test and can reveal pregnancy after a few days (from 6 to 8 days) after ovulation.
How does the pregnancy test work? How is it read?
Each brand of a pregnancy test has a different method of interpreting the results.
The best time for a test is in the morning, because there is a lower amount of beta-hCG in the evening and it is therefore less reliable.
You can do the test on an empty stomach or after eating, alcohol and drugs do not affect the test values.
The description explains how long a test strip must be immersed in the urine.
Then the test strip is placed on a smooth, dry surface and you have to wait a few minutes, as indicated on the packaging.
If the test is negative, only one color line appears in the control zone but no stripes appear on the test area.
If the test is positive, the color lines can be seen both in the control zone and in the test area. These two lines indicate the positive test. The positive line appears directly in the window that displays the result, even a weak line indicates pregnancy.
You should now wait a few days and then repeat the test. The second time, one can get a much stronger line due to the increase in beta-hCG in the body.
Sometimes the result is uncertain, for example if you do not see a line (white test) or the line is not visible (too weak or too bright). This means that the test is worthless, i.e. invalid.
It is likely that the test was not performed correctly and needs to be repeated.
Using a digital stick
You have to remove the cap from the test stick and turn the stick upside down so that the absorbent tip points downwards. Then you hold the rod in the urine flow, which must come into contact with the absorbent surface. Contact is maintained for about 10 seconds to allow sufficient absorption of urine.
The urine should not come into contact with the display, as this can alter the results.
Then close the stick again with the cap and place the test set on a dry surface. The display must point upwards.
Now you have to wait 5 minutes before you get the results. The speed of the results depends on the beta-hCG concentration in the body.
After performing the test, a line is perceived in the control zone (C). This indicates that the test was run correctly.
If the test is positive, a stripe appears in the area marked with “T” and a stripe appears in the area marked with “C”. These two lines indicate the positive test.
If the test is negative, no dash appears in the area marked with “T”.
If the test is invalid, no visible lines appear and the control line remains invisible.
This means that the test has not been performed correctly and must be repeated.
There are also reusable digital pregnancy tests that can be connected to a computer like a USB stick.
After each sample, the test strip must be changed and the test can be repeated.
Homemade pregnancy tests
The use of natural substances in the pregnancy test has been common since ancient times.
Pine Sol All-Purpose Cleaner
As a rule, this product is used as a cleaning agent and lubricant, but Pine-Sol can also be used as a pregnancy test. Put some pine-sol in a vessel filled with urine. If the urine changes color, the test is positive.
- The waiting time is not specified.
- If the color change is only slight, this is difficult to detect, even if the pregnancy is positive.
A mixture of toothpaste and urine can be used to detect pregnancy. A small amount of toothpaste and a small amount of urine are mixed, the foam turns blue if the test is positive.
- The ratio of toothpaste and urine is not specified.
- The time limit at which the foam should turn blue is not specified.
- If you wait too long, the mixture becomes frothy and this can be confusing.
The problem with a home-made pregnancy test is that it’s not very safe and not scientifically explained. It is very likely that the results on a homemade pregnancy test will not be reliable.
How many pregnancy tests are there?
To carry out this examination, it is necessary to go to a clinic or to the doctor. There are two types of investigation, quantitative and qualitative. The first test indicates the concentration of hCG in the blood sample and shows how long the woman has been pregnant.
Also, the qualitative test is performed to confirm the presence of hCG. But you have to wait a day or two for the results.
Most women who take a pregnancy test at home can use it to know whether they are pregnant or not. This type of pregnancy test is inexpensive and fast, the result can be seen in 5 minutes.
Home pregnancy tests are 97-99% safe, so they can be considered reliable.
A positive test result is to be regarded as reliable.
If the positive test is detected on the first day of the delay of menstruation, fertilization may have taken place two weeks earlier.
A negative result is less reliable.
If the test is negative, the test should be repeated after one week or a doctor should be consulted.
Pregnancy test after miscarriage, abortion or extrauterine pregnancy If there is an abortion or extrauterine pregnancy, it is possible to have a positive pregnancy test for a few weeks, even if the woman is no longer pregnant (Van der Lugt et al. – 1985).
The reason for this is that hCG may still be present in the body.
False negative pregnancy test
- Early test
Women who want to get pregnant are usually terribly excited and can take the pregnancy test prematurely. In fact, beta-hCG levels are very low in the first weeks of pregnancy and therefore the test is unable to detect pregnancy.
- Low sensitivity
pregnancy test Women who use a pregnancy test of low sensitivity may get a false negative result in the first weeks of pregnancy.
- Improper use of the pregnancy test
One should use the morning urine, because the beta-hCG is more concentrated there.
If a woman takes the test at another time of the day, a false negative result is more likely.
- Insufficient response time Apart from the factors mentioned above, another reason is the lack of response time
. In other words, if you do not wait as long as stated in the package leaflet, you can get a false negative result.
Reasons for a false positive pregnancy test
The urine sample is contaminated when mixed with any other substances, for example, soap, detergent, cream, etc.
- Improper test application
The result of a home pregnancy test must be read within 10 minutes. After 10 minutes, the test is no longer considered reliable, because the stick changes color after 10 minutes. Thus, the test must be considered invalid after 10 minutes.
- Evaporation line
Each stick for pregnancy tests has two lines. One line turns pink when wetted, the other only turns pink when wetted with a liquid containing beta-hCG.
If the test is wetted, the first line becomes dark pink, while the second line shows a light pink.
If the color of the second line is not as dark as that of the first line, the test result is negative.
Most women confuse this second light pink line with a positive result.
- Chemical pregnancy
At the beginning of pregnancy and before the onset of the child’s heartbeat, the probability of spontaneous abortion is about 15%. After the heartbeat of the fetus is detected, the probability of miscarriage drops to 5%. According to research, this seems to be a common phenomenon when the woman first becomes pregnant. As a result, the result of the pregnancy test may be false positive. The reason for this is that after a spontaneous abortion, beta-hCG levels in the blood decrease, but are still present in the urine.
of medication Treatment with drugs containing beta-hCG can affect the test and give an incorrect result. Women who are being treated for sterility should keep this in mind.
- Faulty pregnancy test Before buying a home pregnancy test
, one should check the expiration date on the product. If the pregnancy test has expired, it is not suitable for correct use. It is also possible that the test is defective.
Frequently asked questions about pregnancy tests
When I took the pregnancy test, the pink line first appeared, but then disappeared after a few minutes. Am I pregnant?
The rapid disappearance of the pink line indicates a negative result. You are not pregnant. You should perform a second test to verify the result.
What should I do if the pregnancy test is negative but I still do not menstruate?
In this case, you should wait another week and then take a new test.
If the result is also negative and the cycle has not yet returned, you should consult a doctor, as the cause may be a disease.
How much does a pregnancy test cost?
The price depends on the brand. The cheapest ones are already available for 8-10 euros, others can also cost about 18 euros.