Ask Ella: How effective is the morning after pill?

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If your regular contraception fails and you find yourself seeking emergency contraception, the wait between taking it and your next period can be a little nerve-racking.

#AskElla is here to put your mind at ease by answering the big questions about the morning after pill and its effectiveness.

How effective is the morning after pill?

There are two types of emergency hormonal contraception (morning after pill) - ulipristal acetate and levonorgestrel.ellaOne contains ulipristal acetate and is the most effective morning after pill.*

Ulipristal acetate is recommended by the Faculty of Reproductive and Sexual Health as the most effective ingredient for emergency contraception.

In a clinical trial it has been shown to be 2.5 times more effective than levonorgestrel when taken within 24 hours of unprotected sex.

No contraception is 100% effective, but of 100 women who take ellaOne, it is approximated that only 2 will become pregnant.

It’s important to note that that emergency hormonal contraception is not 100% effective. “This method of emergency contraception works by delaying ovulation, so if an egg has already been released close to the time of unprotected sex, then you could still get pregnant,” explains Deborah Evans*, pharmacist and sexual health expert.

Deborah’s advice, should you require emergency contraception, is to seek and take it as soon after unprotected sex as possible. Why? Because the morning after pill is more effective the earlier you take it.

It’s important to remember that all morning after pills are for emergency contraception use only and are not effective forms of regular contraception.

Source:  GIPHY

Source: GIPHY


What can impact the effectiveness of the morning after pill?

Throwing Up

The morning after pill is generally well tolerated, however, some women have been known to experience mild side effects, including nausea.

“A small number of women may be sick after taking the morning after pill,” explains Deborah. “If this happens within three hours of taking it, then you may need to take another pill as it may be that not enough of the pill has been absorbed to work.”

Other Medications

Some medications can impact the effectiveness of the morning after pill so it’s vitally important that you give the details of any you’re taking during the consultation process, whether in person with a pharmacist, while filling out a consultation card or when ordering online via ellaOne direct.

“If you have any concerns about your choices and what you should do,” says Deborah, “then your pharmacist or other healthcare professional can advise you on which option of emergency contraception will be best for you.”


There is some evidence to suggest that emergency contraception may be less effective if you have a higher BMI. Deborah notes that “the effectiveness of the morning after pill, could possibly be reduced if you have a BMI above 25, or weigh more than 70kg,” but there is still a lot of debate over these findings.

ellaOne is still recommended for all women regardless of their BMI, but if you are unsure you should speak to your pharmacist or a healthcare professional for more information.  

Unprotected Sex

After having unprotected sex or a contraceptive failure, ellaOne can prevent pregnancy by delaying ovulation. However, this only applies to that specific incident of unprotected sex.

The morning after pill is not effective at preventing pregnancy in any subsequent instances of unprotected sex. Unless you are trying to get pregnant you should not have unprotected sex again after taking the morning after pill.

You should always use some form of regular contraception, such as condoms, to continue to protect yourself and prevent pregnancy.

Don’t Risk It


While there’s no such thing as 100% effective contraception, that doesn’t mean it’s ever worth ‘risking it’. Remember, one millilitre of semen can contain anywhere between 15 million and 200 million sperm ...and it only takes one to get pregnant.

If you aren’t planning a pregnancy, you should always use a some form of regular contraception. If things don’t go as planned, ellaOne is the most effective morning after pill,* available over the counter without a prescription or order online here.

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Want to know more about sexual health and contraception? Send us your questions using the hashtag #AskElla and we’ll answer them. Looking for more answers to your questions? Check out our other #AskElla content here

If you have taken emergency contraception and want to share your story, you can submit it below or by using the hashtag #MyMorningAfter on social.

*For verification visit

*Disclaimer: Healthcare professionals included in this article do not endorse any medicinal brands or products.

ellaOne® 30mg film-coated tablet contains ulipristal acetate and is indicated for emergency contraception within 120 hours (5 days) of unprotected sex or contraceptive failure. Always read the label.

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Leo Kent