\”False\” Positives
Some women find out they are pregnant after using a pregnancy test. After going to the hospital for diagnosis, the doctor told them that they were not pregnant. The result reflected by the pregnancy test paper is a false positive. How is this going?
Why do false positives occur?
This situation may also be a false pregnancy. Physiologists believe that false pregnancy is a combination of physical and psychological \”defects\”. After some women get married, because they are eager to have children, when they see others getting pregnant, they tend to feel envious and anxious compared with their sisters who got married at the same time. When daydreaming or dreaming, the cerebral cortex will form a strong \”hope\” excitement area, affecting the functions of the hypothalamus and pituitary gland, which can eventually lead to menopause. After menopause, under the influence of sex hormones in the body, fat in the lower abdomen will also accumulate. Under the influence of psychological factors such as longing for pregnancy, they think they are pregnant, resulting in \”pregnancy\” reactions such as anorexia, picky eating, and vomiting. Under the psychological effect of \”simulating pregnancy\”, some women will experience an imbalance in the ratio of estrogen and male hormones in their bodies. They may even develop butterfly spots on their cheeks or even feel \”fetal movements\” in their abdomen. This is purely a psychological effect. 
Generally speaking, if a woman takes a pregnancy test at home without any outside guidance, the accuracy of the test results can only reach 51% to 76%. Pregnancy tests can give false positives due to stress or other factors. If the test is done in a lab in front of a doctor, and the doctor can ensure that the test strips are working properly and that the woman is using them correctly according to the instructions, the test accuracy could be closer to 99.9%.
Expert Tips:
Relevant obstetrics and gynecology experts remind everyone that when we use early pregnancy test paper for testing, we must use accurate methods, otherwise the structure will easily produce the above-mentioned The phenomenon of false positives leads to inaccurate results.
80% of women have used test strips before going to the hospital for a pregnancy test
Liu Mingxing, deputy chief physician of the Obstetrics and Gynecology Clinic of the Third Affiliated Hospital of Guangzhou Medical College, said that when women are pregnant, The placenta secretes a substance called human chorionic gonadotropin (HCG).
Among the rapid pregnancy test paper products on the market, whether it is early pregnancy test paper or pregnancy test stick, the principles are mostly the same: they all determine whether they are pregnant by detecting the concentration of HCG in a woman’s urine. The first horizontal bar appears on the test paper. The test strip has been absorbed into the urine. If a second horizontal bar appears, the test result is positive and HCG is present in the urine. \”Under normal circumstances, before the sixth to seventh weeks of pregnancy, the HCG in a pregnant woman\’s body will double every other day. The higher the concentration of HCG in the urine, the darker the color of the second horizontal bar.\”
Liu Mingxing said that these products are now widely used among women of childbearing age. 80% of women who go to hospital outpatient clinics every day to check whether they are pregnant have already done self-examination at home. \”Positive HCG does not necessarily mean pregnancy, and not seeing the second horizontal bar does not necessarily mean that you are not pregnant. It may just be that the color is too light to see clearly.\” Liu Mingxing pointed out that when using early pregnancy test strips, pay attention to \”appropriate time” and “right place”. People to People avoids false positives of “yes” as “no” or false positives of “no” as “yes”.
The results will not be known until at least 10 days after intercourse.
The reporter learned that there are early pregnancy self-test products that claim to be able to test with test strips on the day of suspected pregnancy. Some couples who are eager to know the results of \”baby giving birth\” or who do not want to have a baby so soon rush to buy test strips the day after sex. You usually won\’t see the second horizontal bar when you take the test, but that doesn\’t mean you\’re not pregnant.
Liu Mingxing said that at this time, it is almost difficult to use early pregnancy test strips to detect whether she is pregnant, because it takes several days for sperm and eggs to combine into fertilized eggs, implant into the uterus, and form eggs. embryo. HCG cannot be detected until several days after pregnancy. It appears in the blood and may not be detected at first because the amounts are so small.
If a urine test is performed too early, a negative reaction may be in error.
If you want to know the accurate results as soon as possible, you can refer to these two methods provided by Liu Mingxing to calculate the time:
Using the last menstrual period as the standard: If menstruation has been compared Accurate, the cycle is 28-30 days, then the test strip can detect a weak positive from the 3rd to 5th day after the menstruation is delayed.
For example, if your menstrual cycle is 30 days, you got your period on the 11th of last month, and then you had sex, you can use a pregnancy test from the 3rd to 5th day after the 11th of this month. Take a test, it will be around the 14th to the 16th. But for women with irregular menstruation, this method is not suitable.
According to the time of sexual intercourse: If a woman becomes pregnant during a certain sexual intercourseIf pregnancy is successful, a weak positive result can be obtained by using a pregnancy test paper 10 days after sexual intercourse. It usually takes 14 days to get clear results.
In addition, the concentration of HCG in morning urine is higher, so it is best to use the urine after getting up in the morning for self-test.
If the test paper gets wet, it will affect the results.
Liu Mingxing said that when buying early pregnancy test strips or pregnancy test sticks, you should choose those produced by regular manufacturers. When purchasing, you should pay attention to whether the packaging is intact and avoid storing it in a humid place after taking it home.
Check whether the product is still within the expiry date before use. Since most early pregnancy test products are used in the bathroom, care should be taken when taking them apart to avoid letting the test paper get wet, which will affect the results.
