What’s the lowdown?
- Levonorgestrel morning after pills can be taken up to 3 days after unprotected sex, while ellaOne can be taken up to 5 days after unprotected sex
- ellaOne is more effective at preventing pregnancy than levonorgestrel-based morning after pills
- A copper IUD is the most effective method of emergency contraception, regardless of weight or BMI
- You can buy both types of morning after pill from The Lowdown, plus an extra dose for future emergencies
What are the different types of morning after pill?
There are two different morning after pills, each containing a different type of synthetic hormone. The type and dose of morning after pill that will be best for you will depend on things like; how long ago you had unprotected sex, your BMI, and whether you use hormonal contraception. We’ll talk more about these in a second, but here’s a super quick overview of the different types of morning after pill…
- Levonorgestrel morning after pill (also known as Levonelle, Ezinelle or Plan B): this contains the synthetic hormone levonorgestrel and can be taken up to 72 hours (3 days) after unprotected sex
- ellaOne morning after pill: this contains the synthetic hormone ulipristal acetate, and can be taken up to 120 hours (5 days) after unprotected sex
For the lowdown on levonorgestrel and ellaOne, check out their contraception pages or get stuck into our guide to emergency contraception, which explains exactly how they work in more detail.
Which morning after pill is more effective?
The morning after pill works by delaying ovulation (the release of an egg from the ovary). The earlier you take the morning after pill after unprotected sex, the better the chances are of it being taken early enough to delay ovulation and lower your chances of becoming pregnant. If used correctly, studies suggest the morning after pill is around 97-98% effective at preventing pregnancy.⁵
Research¹ shows that the ellaOne morning after pill is more effective at preventing pregnancy than levonorgestrel-based morning after pills, with only 1-2% of users becoming pregnant after using ellaOne, compared to 0.6-2.6% of people who take a different morning after pill.
If you vomit within 2 hours of taking a levonorgestrel morning after pill, or within 3 hours of taking ellaOne, the effectiveness of the pill will be reduced and you will need to take another dose. Alternatively you will need to have an emergency copper coil (IUD) fitted to prevent pregnancy, which is actually the most effective form of emergency contraception – less than 0.1% of people who have one fitted after unprotected sex will get pregnant.
The effectiveness of the morning after pill may also be reduced if you have a higher BMI, which we’ll come on to in a moment. This is something to consider when discussing your options with your healthcare provider.
Which morning after pill is the best if you have a high BMI?
A 2015 study² found that levonorgestrel-based morning after pills are less effective for individuals with a BMI of 26 or above, or weighing over 70kg even with a normal BMI. Some research³ has suggested that doubling the dose of levonorgestrel increases effectiveness, while another study⁴ suggests this doesn’t make a difference. Either way, the current UK guidance for emergency contraception⁵ recommends that if the copper IUD isn’t suitable and you have a BMI of 26 or over, or weigh over 70kg, you should use ellaOne, or if this isn’t suitable then a double dose of levonorgestrel.
Similarly, ellaOne may be less effective if you have a BMI above 30, or weigh more than 85kg.⁵ Again in this case, consider an emergency copper IUD which is not known to be affected by weight or BMI. You can still use ellaOne, or double dose levonorgestrel if this is not suitable. A double dose of ellaOne is not recommended.⁵
Which morning after pill is the best if you use hormonal contraception?
If you’ve used either the combined pill, patch, ring or progestogen-only pill in the last 7 days before taking the morning after pill, the best morning after pill for you to use would be levonorgestrel-based pills. This is because the hormones in these contraceptives can reduce the effectiveness of the ulipristal acetate in ellaOne.
If you require emergency contraception because your injection, implant, hormonal coil (IUS) or copper coil (IUD) has run out and needs replacing, speak to your healthcare provider about the best morning after pill for you.
When can you start hormonal contraception after using the morning after pill?
If you have taken the levonorgestrel morning after pill, you can start any form of long term hormonal contraception immediately after taking it.
If you have taken ellaOne, you will need to wait 5 days before starting hormonal contraception, as the progestogen found in hormonal contraception can stop ellaOne from working as effectively. Avoid sex or use condoms during this time, plus the number of days that takes your contraceptive to start working.
Which morning after pill is best if you use other medication?
There are quite a few medications⁶ that can interfere with the effectiveness of the morning after pill – but this doesn’t mean you can’t use it. It’s important that you tell your healthcare provider – GP, nurse or pharmacist – about any other medications you may be taking, even herbal over the counter remedies. Particularly if you have severe asthma, use epilepsy medication, have HIV or tuberculosis, are on certain antibiotics, use St John’s Wort or take medication for stomach acid.⁷ ellaOne may not work if you’re already taking one of these medicines but levonorgestrel can still be used. Your healthcare professional may advise increasing the dose.⁷
If you’ve made a decision on which morning after pill is best for you, but aren’t quite sure how to get it, check out our complete guide to getting the morning after pill, or buy it directly from The Lowdown in a few clicks.
Tags
- NHS UK, How effective is emergency contraception [Accessed 21st November 2022]
- Nathalie Kapp, Jean Louis Abitbol, Henri Mathé, Bruno Scherrer, Hélène Guillard, Erin Gainer, André Ulmann, Effect of body weight and BMI on the efficacy of levonorgestrel emergency contraception, Contraception, Volume 91, Issue 2, 2015
- Alison B. Edelman, Ganesh Cherala, Steven W. Blue, David W. Erikson, Jeffrey T. Jensen, Impact of obesity on the pharmacokinetics of levonorgestrel-based emergency contraception: single and double dosing,
Contraception, Volume 94, Issue 1, 2016 - Edelman, Alison B. MD, MPH; Hennebold, Jon D. PhD; Bond, Kise PSM; Lim, Jeong Y. PhD; Cherala, Ganesh PhD; Archer, David F. MD; Jensen, Jeffrey T. MD, MPH. Double Dosing Levonorgestrel-Based Emergency Contraception for Individuals With Obesity: A Randomized Controlled Trial. Obstetrics & Gynecology: July 2022 – Volume 140 – Issue 1 – p 48-54 doi: 10.1097/AOG.0000000000004717
- FSRH, Guidelines for emergency contraception (March 2017, Amended December 2020) [Accessed 21st November 2022]
- Drugs.com, Morning after pill interactions [Accessed 21st November 2022]
- NHS UK, Emergency contraception [Accessed 21st November 2022]
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