Though contraceptives are designed to prevent conception, they are not entirely fool-proof. There are several ways of getting pregnant on birth control.

Hormonal birth control pills are designed to prevent women from getting pregnant. When used correctly, both of the most common types of birth control pills are considered to be over 99% effective in preventing the occurrence of pregnancy. Unfortunately, getting pregnant on birth control is not as uncommon as one would think. This is because many women make mistakes when taking the pill. Though is seems like just taking a pill once a day is a fool-proof way of preventing pregnancy, there are several mistakes that women commonly make.

The most common reason why women end up pregnant while taking birth control is that they start the pill at the wrong time of the month. Many women make the mistake of starting the pill later in the cycle than they should, and they do not take extra pills to make up for it. In fact, if you start birth control just three days late, it might mess up the entire month. If you start one day late, you should take the missed pill along with the next day's dosage, then continue taking one pill per day as normal for the rest of the cycle. When you're two days late, you need to take the two missed doses. Anytime you do not start taking pills on the right day, you are actually at risk for becoming pregnant. Another common problem is that women simply forget to take their pill. Missing one day during your cycle shouldn't be a big deal as long as you realize your mistake and take the missed pill within 24 hours. If you miss two days in a row, however, it may not be possible to "catch up" during that cycle, and a back up method of birth control should be taken.

Because it is human nature to make mistakes, most women find themselves unable to never miss a dose or start on the wrong day of their cycle. When this happens, it is important to use a back up method of birth control until the next cycle or call your doctor for further advice. If you do become pregnant while taking birth control, you should stop taking the pill as soon as the pregnancy is discovered as it is possible for birth control to cause birth defects when taken late in pregnancy.