After taking birth control pills HCG (urine test) weak positive may be already pregnant, but also may be the pregnancy test stick failure, the test method is not right and other reasons. 1. pregnancy: oral emergency contraceptive pill contraceptive failure is not uncommon, especially taking time more than 72 hours after sex Oral short-acting contraceptive pill leakage can also lead to contraceptive failure. 2. Failure of the pregnancy test, incorrect test method: the pregnancy test has expired, or the quality of the pregnancy test produced by the manufacturer is not qualified resulting in weak positivity, or the test method is incorrect. After taking the contraceptive pill urine test HCG weak positive, you need to go to the hospital for further blood tests to confirm the diagnosis and examination, such as blood HCG, in order to rule out the possibility of pregnancy, and then develop individualized diagnostic and treatment programs.