Your urine is too diluted
A high concentration of hCG in your urine is required for an accurate positive pregnancy test result, and this concentration can vary depending on a number of factors.
You checked the results too soon
Your pregnancy test should come with instructions about how long you will need to wait between taking the test and checking your results — the wait time is usually about one to two minutes. This is because the antibodies in the test need time to sense the hCG in your urine and display a result.
Even if you are pregnant, if you check the test before the waiting period is up, you might see a negative result.
What Can Cause a False Negative Pregnancy Test?
There are a few possible reasons why a pregnancy test could come back negative.
Timing, or testing too soon, is “almost always” the cause of false negative pregnancy tests, according to Dr Price.
The placenta may not have produced enough hCG for the test to detect it if someone takes the test too early in their cycle. This might also happen if a person skips taking a pregnancy test after having sex for too short of a period of time. As soon as your period is missed, you should test.
If the urine used for testing is too diluted, this is another factor that could result in a false pregnancy test. There might not be enough hCG in the urine if it is not concentrated enough for the test to detect it.
Because of this, Dr. Before performing a pregnancy test, Price suggests waiting a couple of hours before drinking anything. First thing in the morning, urine also tends to be less diluted because you probably didn’t drink anything over night.