The Morning After Pill comes with a pregnancy test. No urine pregnancy test will show a positive result until 7 to 10 days after conception; therefore, a positive pregnancy test at this point means that the woman is pregnant from an earlier sexual encounter.
The instructions in the kit say that “it will give you ‘peace of mind’ to know you are not pregnant from sex earlier in the month or in previous months.”
The literature provided in the kit states over and over that women who are pregnant should not take the Morning After Pill. The effects of doing so are not known because no direct studies have ever been done.