You cannot use test strips to detect pregnancy before your period. If you use a test strip to detect pregnancy before menstruation, the pregnancy in this case is relatively short, usually can not accurately detect pregnancy. The main reason for this is that the fertilized egg has not yet settled in the uterine cavity in the period before menstruation. It is recommended that you use a pregnancy test or pregnancy test stick to detect pregnancy about 7 to 10 days after menopause. During this time, the level of human chorionic gonadotropin in the urine is relatively high, and testing at this time is more likely to detect pregnancy. If you want to know whether you are pregnant or not, it is recommended that you go to a specialized hospital for a blood test to check the human chorionic gonadotropin in your blood, which can usually be measured more accurately about 25 days after your period. It should be noted that before menstruation can not be detected through the test paper to determine whether pregnancy, in addition to the above detection methods, you can also go to the hospital to carry out urine pregnancy test, blood HCG test, blood progesterone test, pelvic ultrasound and so on to determine whether pregnancy.