Morning After Pill Effectiveness

The effectiveness of the morning after pill, also known as emergency hormonal contraception, depends on various factors, including which pill you take and when you take it. 

How effective is the morning after pill?

Morning after pills that contain the active ingredient levonorgestrel, such as LoviOne, must be taken within three days (72 hours) of unprotected sex in order to be effective. Medicines that contain ulipristal acetate have to be taken within five days (120 hours) to be effective.

But what exactly does effective mean? Well, figures cited by the NHS suggest that between 0.6% and 2.6% of women who take levonorgestrel within the recommended timeframe will become pregnant. For treatments containing ulipristal acetate, this number is between 1% and 2%. Morning after pills are most effective when taken within 24 hours of unprotected sex or contraception failure.

LoviOne and other morning after pills containing levonorgestrel are up to 99% effective when taken within 24 hours, reducing to 84% when taken within 72 hours following unprotected sex.

Morning after pills containing ulipristal acetate however remain up to 98% effective for up to five days after unprotected sex.

It’s important to be aware that the morning after pill is not as effective at preventing pregnancy as using other contraception methods regularly and should not be used as a regular form of contraception. For example, our progestogen-only contraceptive pill Lovima is 99% effective at preventing pregnancy, as long as you take it correctly at the same time every day from the beginning of your menstrual cycle. You can use Lovima as a follow-on daily oral contraceptive after taking the LoviOne morning after pill.

What can impact the effectiveness of the morning after pill?

Certain things can reduce the effectiveness of the morning after pill. For example, a number of complementary or prescribed medicines can lower its effectiveness. A pharmacist will be able to advise you on this.

If you are sick within three hours of taking levonorgestrel or ulipristal acetate, it’s important to speak to your pharmacist as you’ll need to take another dose. Alternatively, you could have an intrauterine device (IUD) fitted.