The chances of getting pregnant on birth control, if you take it correctly, are actually pretty low.
Women have been taking the pill as birth control since the 60′s to help prevent unplanned pregnancies, and while birth control pills are effective at preventing pregnancy in 99% of all cases, there have been rare occurrences where some women have gotten pregnant.
Forget a day or two?
Usually it’s because the she has forgotten to take the pills on one or more days, or even taken it much later in the day that usual. This can be easy to do especially with today’s busy lifestyles. To be effective birth control needs to be taken at the same time every day. Miss a day and you are at a higher risk of conceiving if you are sexually active.