Yes it’s possible for several reasons: If you don’t take it every day, if you need a higher dose of hormones than you are on. and some people are just really fertile and get pregnant on the birth control pill even if they take it every day. If you think you might be pregnant, you should check a pregnancy test.  However, if you take your medicine everyday and there isn’t any unusual spotting, then it’s unlikely that you would get pregnant. The chance of pregnancy on the birth control pill, if you take it right, is like 3/1000 women. And 9/100 in “normal use” meaning with errors.