A seventh brand was recently approved. The first dose of contraceptive pills must be followed precisely 12 hours later by a second dose. If those 100 women all took the emergency contraceptive pills, on average, only two would become pregnant. Waldron says a Planned Parenthood client is given a pregnancy test first, because if she has already become pregnant, it will do no good to take the emergency contraception pills and suffer their side effects. Those effects are mainly nausea in about half of women taking the pills, and vomiting in about 20 percent.
Some providers prescribe the pills to women for use in an emergency.
Waldron says, but Planned Parenthood isn't doing that yet. Because the makers of birth control pills haven't asked the FDA for permission to label their products with information on emergency contraception, such instructions don't come with the pills. Therefore, a provider has to give special information to a woman for emergency use. For most kinds of contraceptive failure, emergency contraception is straightforward. But Princeton's Trussell says that one situation that isn't so clear is when a woman already taking birth control pills misses one or more pills and worries that she might be at risk of pregnancy.