Early pregnancy test paper is a simple and easy tool to detect whether you are pregnant or not. If the color is particularly light, according to the result, it is considered weakly positive and cannot be used to determine whether you are pregnant or not, which can be caused by the following reasons: 1, short pregnancy or biochemical pregnancy: due to the short pregnancy time, the hormone level in the body is relatively low, resulting in the result is not obvious. This is a normal test result, there is no need to be too nervous, if the menstruation still has not come, you can test again; biochemical pregnancy although there is conception in bed, but the HCG only has a transient elevation, often accompanied by vaginal bleeding; 2, not pregnant: generally before the menstruation will also have the possibility of weak positive test paper, because the sensitivity of early pregnancy test paper to detect pregnancy is not very high, easy to be affected by other hormones. If the early pregnancy test paper is weakly positive, the diagnosis can be assisted by a blood test for HCG. If the test result is pregnant, it is necessary to monitor the rise of HCG, combined with progesterone and ultrasound to determine if the pregnancy is normal in utero.