Experts recommend doing pregnancy test 12~14 days after IVF embryo transfer, and it is not recommended to do the test too early. The early detection of a deep and light bar on the tenth day of embryo transfer, that is, the early pregnancy test paper detects a weak positive, which may be caused by pregnancy, improper use of the test paper, or bad quality of the test paper. 1. pregnancy: embryo transfer on the tenth day because the pregnancy time is relatively short, so the amount of human chorionic gonadotropin secretion in the body is less, the check will appear a deep and shallow situation, can go to the hospital for blood HCG test, to get accurate results. 2. Improper use of test strips: If the test strips are used improperly and the urine is over-diluted, a weak positive result may occur, in which case it is still recommended to draw blood for HCG test to obtain accurate results. 3. Bad quality of test strips: If the test strips are expired or damp, it will lead to error in the result.