Does ellaOne work if you've already ovulated?

Emergency contraception pills, like ellaOne, only work if you take them before ovulation. This is the point in your menstrual cycle when the ovary releases an egg.

They will not be effective after you have ovulated. This is because they work by delaying ovulation so there’s no egg in the womb to be fertilised.

Because it can be hard to know exactly when you’ve ovulated, if you have had a pregnancy risk and do not want to be pregnant, it’s recommended that you take emergency contraception. Even if you don’t know what point you’re at in your cycle. 3 weeks after taking the pill, you can do a pregnancy test to check that it has been effective.

Find out how to predict when you ovulate.

Both these types of emergency contraception work by delaying ovulation. You can take ulipristal acetate up to 5 days (120 hours) after pregnancy risk. Levonorgestrel must be taken in the first 3 days (72 hours) after pregnancy risk.

The non-hormonal coil, or IUD, is the most effective type of emergency contraception and is effective if used up to 5 days after ovulation. It needs to be fitted within 5 days of pregnancy risk. It can also be fitted if you are within 5 days of the earliest time that you are expected to ovulate that cycle. If you like, you can keep using the coil as a long-term form of contraception.

Reviewed by Dr Paula Baraitser. Medical Director
Last updated at: 05 May 2023