ellaOne, known as ella in the US is a new emergency contraception that can be taken up to 5 days after intercourse. It blocks Progesterone which the uterus requires to sustain a fetus. ellaOne will reduce the effectiveness of any hormonal birth control, so it is important to abstain from sex, or use another form of birth control until your next regular period.
Do not take ellaOne if you have uncontrolled asthma or you are nursing your baby. ellaOne has not been tested to determine if it would damage an existing pregnancy, so do a pregnancy test before taking ellaOne.