Yes, there is still a chance that you could become pregnant. This is because Emergency contraception (Plan B) lowers the chances of getting pregnant, but it is not as effective as using a regular long term method of birth control.
Usually Plan B is taken after unprotected sex and it is not known how well it will protect against pregnancy when you take the pills before you have sex.
However, if you take pills within 24 hours of having sex, they should provide some protection against pregnancy.
If you do not get a period within 2 – 3 weeks, we recommend that you get a pregnancy test done.
Have a look at the following links for more information on Plan B
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