Emergency contraceptive drugs generally do not cause false positives. The main components of emergency contraceptive drugs are estrogen and progestin, and the content is relatively large, mainly by inhibiting ovulation and interfering with the fertilization of eggs, thus playing a contraceptive role. As long as you are not pregnant, you will not get a positive result by using early pregnancy test paper. If you are not sure, you can also see your doctor for a blood chorionic gonadotropin test, if the value is high, such as greater than 25mIU/mL, you can diagnose pregnancy; you can also wait patiently, if your period is overdue for more than 10 days, you can see your doctor for an ultrasound test to determine whether you are pregnant. Even if you are pregnant after sex, it takes at least 10 days to detect whether you are pregnant or not, and the time is too short to do so.