False negative urine test for early pregnancy

After a woman finds out she is pregnant, she will go to the hospital for a checkup to make sure the fetus is developing normally. Generally speaking, pregnant women are examined through B-ultrasound or urine test. The positive or negative urine test can be used to determine whether a woman is pregnant. But some women find that their urine tests are false negative, but they are indeed pregnant. So, what is the reason for false negative early pregnancy in urine test?

1. What is a false negative pregnancy test?

There are several main reasons why a pregnant woman may get a negative result in a urine pregnancy test: first, the pregnancy is still in the very early stages and the hormone level in the pregnant woman's urine is still very low and cannot be detected; second, the pregnant woman drinks too much water, which dilutes the concentration of human chorionic gonadotropin in the urine; third, there is a problem with the quality of the test paper. Therefore, in clinical practice, β-hCG is measured in the blood for quantification, because blood is more accurate and sensitive than urine, and it can usually be detected eight or nine days after fertilization.

When doing a urine pregnancy test, be sure to use first morning urine. This is because morning urine is concentrated and contains higher levels of hormones. In order to increase the positive rate of the test, you should try to reduce your water intake the night before. Now you can do this experiment at home, and do it several times when you have questions.

For women who are preparing to become mothers, if they encounter amenorrhea and a negative urine pregnancy test, they should not take menstruation-regulating drugs casually. It is best to consult a doctor to avoid accidentally taking drugs that may have adverse effects on the fetus.

2. How long does it take for an early pregnancy test paper to detect

To know how long it takes for an early pregnancy test to detect pregnancy, you must first understand how long it takes for HCG to be produced after pregnancy.

1. Waiting time for sperm and egg to combine after intercourse: 1-3 days. After intercourse, it takes some time for the sperm to merge with the egg. Sometimes he may have to wait for 72 hours for the shy egg to mature and come out (ovulate) before he can have sex.

2. The time it takes for the fertilized egg to pass through the fallopian tube and enter the uterus: 3-4 days. After the sperm and egg successfully combine, the fertilized egg develops and moves through the fallopian tube toward the uterus, and it takes about 3-4 days to reach the uterus.

3. The time the fertilized egg wanders in the uterus: 2 to 3 days. After the fertilized egg enters the uterus, it will wander around in it for a while before it finds a place to settle and finally implants in the uterus.

4. After implantation, the fertilized egg is connected to the uterus through the placenta. The placenta produces HCG. HCG will appear in the urine, but the concentration is very low at the beginning. Sometimes the early pregnancy test paper will not be able to detect it, or only two lines will be shown, one dark and one light. The lighter ones may be very light and almost invisible. Some people also call this faint bar a "watermark".