Ovulation is a result of a surge in luteinising hormone (LH). ellaOne® delays ovulation by inhibiting or delaying the LH surge.1
If the woman is due to ovulate tomorrow or the next day after unprotected sex, when the risk of pregnancy is highest, only ellaOne® can delay ovulation.1
This is when LH has started to surge but has not yet reached the peak. At this time, levonorgestrel will not prevent the follicle from rupturing whereas ellaOne® is highly effective.1
Intake after LH surge, but before peak1
If she is due to ovulate 3 or more days after unprotected intercourse, both ellaOne and levonorgestrel can delay ovulation .1 However, ellaOne® remains more effective in preventing follicle rupture and therefore unintended pregnancy 1.
Intake before LH surge1
If the woman has already ovulated, or is due to ovulate, in the immediate 24 hours of unprotected intercourse, no emergency contraceptive pill help1
This is because the LH has already peaked, meaning the ovulation process is at a point where it cannot be stopped, or has already happened.
Intake after LH surge 1
ellaOne® can delay ovulation even when it is about to happen (when risk of fertilisation is highest)1