The test paper refers to the early pregnancy test paper, 13 days of intercourse theoretically with the early pregnancy test paper can be tested, especially in the ovulation period after 13 days of intercourse, the early pregnancy test paper can be measured. Under normal circumstances, the fertilized egg will enter the uterine cavity on the 6th to 7th day after fertilization and start to secrete human chorionic gonadotropin, generally in the 1st to 2nd day after the implantation of human chorionic gonadotropin can be detected by blood test to determine whether the pregnancy. And the use of early pregnancy test paper for detection, mostly in the 10 ~ 16 days after fertilization can be detected. Therefore, the use of early pregnancy test paper for 13 days after intercourse will more often than not be detected. The use of early pregnancy test paper for testing should also pay more attention to strictly follow the instructions, and can not drink too much water before the test, so as not to affect the results of the test.