is effective when taken within 72 hours of conception. Its effectiveness decreases the longer from the unprotected intercourse
that you take it. The overall effectiveness is 7 in 8. That means for every 8 women who would have gotten pregnant through midcyle unprotected sex, 7 will not. The Plan B you took April 4 was less effective for sex on April 6 and 7 but still somewhat protective, as long as the sex on April 7 was not more than 72 hours from the Plan B.