It is recommended to wait until after the delay in your next menstrual period to take a pregnancy test. This is usually around the time of your scheduled week off from birth control pills. Taking a test at this time increases the accuracy of the results, as most companies guarantee a high level of accuracy (often 95% or higher) at this point. It is possible to take a test earlier, but it may be less precise and more likely to give a false negative result. It's important to carefully read the packaging instructions and consult with a pharmacist for guidance. If you have any doubts about the effectiveness of your birth control or if you had unprotected intercourse within the past 5 days, it may be wise to speak with a pharmacist about emergency contraception options.