No, it is not a guarantee. In fact, missing only one pill does not significantly increase your risk of pregnancy. Hopefully, you made your pill up correctly by taking it as soon as you remembered and then taking your next pill at the regular time or by taking two pills the next day.
When you are on the pill, you do not ovulate. That is how the pill works. It changes the hormone levels in your body (it makes them similar to the levels produced when you are pregnant). When your brain sees these different hormone levels, it thinks you are alrealy pregnant and sends a message back down to your ovaries instructing them not to ovulate. As long as your brain sees these hormone levels, you do not ovulate. However, if you miss two or more hormone pills in a row or if you forget to take the very first hormone pill in a new pack, your hormone levels may go back to where they were before you were on the pill, and then you may ovulate. (Your hormone levels will build up during your three weeks of hormone use and will continue to protect you from pregnancy during you period week.) That is why it is so important to take your pill at the same time every day – to maintain those hormone levels.
Of course, even when used perfectly, the birth control pill is not 100% effective. If you miss your next period, take a pregnancy test just in case.
25. June 2012
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