One of the ways Plan B helps to prevent pregnancy is by delaying ovulation. That is why it is recommended for use after unprotected intercourse. Taking it a day or two prior to unprotected sex may decrease its effectiveness.
When taken within 24 hours after unprotected sex, Plan B can be about 80% at reducing the risk of pregnancy. Research has shown that is can be also be effective when taken as long as 120 hours (5 days) after unprotected sex.
If your next period is more than 1 week late, do a pregnancy test.
27. February 2012
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