Ask Ella: How do I know if the morning after pill has worked?


So, you’ve braved the walk to the pharmacy, leaned over the counter, asked for the morning after pill and taken it. Now what?

Do you head home and wait for some mystical sign to tell you you’re not pregnant? Does an angel fly through your window to give you the good news, “It’s worked!”? What happens after you’ve taken the morning after pill?

Your #MyMorningAfter stories make it clear that many women still have questions about the morning after pill. There’s a lot riding on one little pill, so it’s only natural for you to have a lot of questions: from how it works to if it will affect your body. Allow us to answer some of your queries…

How effective is the morning after pill?


This is one of the most frequently searched questions about the morning after pill. To find out more, we spoke to pharmacist and sexual health expert, Deborah Evans.

Deborah has been working as a pharmacist for over 30 years, and she is able to answer all our questions about the morning after pill.*

“If you have had unprotected sex, then it’s understandable that you may be worried and anxious about getting pregnant” says Deborah, “however, taking the morning after pill as soon as possible can reduce your risk of pregnancy.

Sperm can survive in the female reproductive system for up to five days. The morning after pill works by delaying ovulation which means that no egg will be released and any remaining sperm will have nothing to fertilise.

Taking the morning after pill as soon as possible can reduce your risk of getting pregnant. ellaOne is the most effective morning after pill. If taken within 24 hours after unprotected sex it is estimated that there is only a 9 in 1000 chance that you could get pregnant.

Read next:
How effective is the morning after pill?
How do I get the morning after pill?
What are the morning after pill side effects?

Does the morning after pill affect your period?

“I was concerned about side effects - I have terrible periods and as I’d never taken it before I was concerned about how it might interfere with my cycle.” Anonymous, 33, London


The effect the morning after pill might have on your period is another issue that crops up in many of your stories. Deborah explained that taking emergency contraception can affect your next period: “It can make it late (by up to 7 days) and the bleed could be slightly lighter or heavier than normal” she says.

For many women, a late period after taking the morning after pill might be the last thing they want and can “make you even more concerned about whether it has worked”, adds Deborah. Remember that a delayed, early, light or heavy period is a normal side effect of the morning after pill that women can experience.

How do you know whether the morning after pill has worked?

“I wasn’t really worried about side effects, more worried about it working or not.” – Anonymous, 22, London

We’re guessing this might be your next question. We’ve mentioned how effective our research has shown ellaOne to be, but of course, no contraception is 100%.

The only way to know that the morning after pill has definitely worked is for your next period to arrive.  

This might not be what you wanted to hear, but it’s important not to panic. There are loads of online resources (like this website) which have all the information to help to ease your mind until good old aunt flow turns up.

It is a good idea to get to know your menstrual cycle. Your cycle is more than just your period, understanding it can help you to spot the signs for when your period is due and can make it easier to tell when it’s late.

Should you do a pregnancy test after taking the morning after pill?

“A few weeks after I had taken the morning after pill I began to throw up, and I realised I had missed my period.”Anonymous, 22, Oxford

If you’ve taken the morning after pill and you’re now frantically doing menstrual maths, it might be time to take a pregnancy test. “It’s the only way to be sure,” says Deborah Evans.

Now, this doesn’t mean buy a test straight after taking emergency contraception. This will be too early to be accurate.

“You can carry out most home pregnancy tests from the first day of your missed period,” says Deborah. “If you don’t know when your next period is due, you should do the test at least 21 days after you last had unprotected sex”.

The reason for this is that the hormone that pregnancy tests detect (hCG – human chorionic gonadotrophin) begins to be produced only 6 days after fertilisation.

If your test appears negative but you still suspect you might be pregnant, then you should make an appointment with your GP as soon as possible for another test. False negatives may occur from time to time, but a positive pregnancy test is almost certainly correct.

If your period is late by more than seven days, you should take a test. Other signs of pregnancy to look out for include: “feeling or being sick, tiredness, breast tenderness or soreness and needing to pee more often” according to Deborah.

If the test result is positive it is important that you go and speak to your GP. They will be able to discuss your options with you and help you decide what’s best for you.

There are many other fantastic charities to help women to make this decision, including BPAS and Marie Stopes if you are considering having a termination.

You can even discuss your options with a nurse over the phone. Remember: it’s your body and it’s your choice.

After the Morning After

If you have unprotected sex, and do not want to get pregnant, ‘risking it’ isn’t a good idea. If you take ellaOne within 24 hours of having unprotected sex your chances of getting pregnant decrease to just 9 in 1000.

Have you ever taken the morning after pill and wished you knew more about it? Share your experience below and join a community of women breaking this taboo.

*Deborah Evans does not endorse any medicines or branded 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