The US CDC (Centers for Disease Control and Prevention) reports that for every 100 couples that use oral birth control pills alone, 9 of those couples will experience a pregnancy any given year. That’s…okay, but there are a few factors to consider.

This rate takes into account all of those who do not use the pill appropriately. Specifically, in order to be the most effective, pills need to be taken around the same time every day (ideally within the same hour or so) with no missed pills. The 9% rate includes those individuals who do not take the pill around the same time every day and/or miss pills. So if you want a pregnancy rate that is lower than 9%, take the pills as directed.