The active ingredient in ella® is ulipristal acetate, whereas other morning after pills contain an active ingredient called levonorgestrel. Ulipristal acetate has been shown to be highly effective and the agent of choice for many women.
ella® gives you a longer window to access emergency contraception, but both medicines are more effective the sooner you take them. ella® can still be effective for up to 120 hours (5 days) afterwards whereas levonorgestrel can be effective emergency contraception for up to 72 hours after unprotected sex.
If ella® is taken as directed, it will reduce the chances of your becoming pregnant. However, ella® is not effective in every case. ella® is only to be used for a single episode of unprotected intercourse. Be sure to use a barrier method until your next period. Wait 5 days after using ella® to start/resume use of hormonal birth control methods. ella® and other emergency contraceptives may be less effective in women with a body mass index (BMI) >30 kg/m2