Emergency contraception can be used as a last attempt to prevent unintended pregnancy, for example after having unprotected sex or when a contraceptive method has failed (e.g. condom breaking). In certain circumstances when using Natural Cycles, you might consider using emergency contraception depending on where you are in your cycle.
What You Need to Know
There are two options to choose from; the emergency pill or the copper IUD.
Copper IUDs are the most effective method of emergency contraception and can be inserted up to 5 days after having unprotected sex1.
Depending on what type of emergency pill you take and where you are in your cycle, it should be taken within 72 - 120 hours of having unprotected sex2.
Understanding how fertile you are, based on where you are in your cycle, can help you and your healthcare professional decide on the best method.
You can continue to use Natural Cycles as normal, make sure to write #EmergencyPill or #EmergencyIUD in the ‘Notes’ section of the app on the day you took the pill or had an IUD inserted.
How Effective is it?
This depends on where you are in your cycle. There is a risk of becoming pregnant in the 6 days prior to and including ovulation (the fertile window). Emergency contraceptive pills contain either levonorgestrel or ulipristal acetate and work to delay ovulation2,3. They can be effective if taken before ovulation happens, during the most fertile time of the cycle. The copper IUD works by stopping implantation of a fertilized egg, it can be used at any point during the fertile window and for a few days after ovulation has occurred. Keep in mind that this is different to mifepristone (RU-486 or ‘abortion pills’) which act to terminate an established pregnancy, where implantation of a fertilized embryo has occurred.
You can use Natural Cycles to understand where you are in your cycle. In the ‘Graph’ view you can see where any given day is in relation to ovulation day.
Using Natural Cycles after Emergency Contraception
• Add #EmergencyPill or #EmergencyIUD into the ‘Notes’ section of the app on the day you took the pill or had an IUD inserted.
• Continue measuring your basal temperature and entering it into the app as normal.
• Continue to abstain or use barrier protection during red days.
• Spotting or light bleeding can happen soon after using emergency contraception - this is not equivalent to your period.
• If your period is delayed by more than 1 week, take a pregnancy test.
When you use #EmergencyPill, the Natural Cycles algorithm will take into account how the additional hormones in the emergency contraceptive pill will affect your temperature measurements and cycle. The copper IUD is non-hormonal, so your temperature won’t be affected. It is common that the cycle in which you use emergency contraception might be slightly different, longer or shorter than usual for you.
Please read Natural Cycles' Instructions for Use for more information on how to manage your app following use of emergency contraception.
Using Natural Cycles requires that you abstain or use a barrier method, such as condoms, during intercourse on red days. Read more here.
This information is provided for educational purposes only and is not intended to replace the advice of your healthcare professional. Please consult your healthcare professional if you are unsure about using emergency contraception.
1. Cleland K, Zhu H, Goldstruck N, Cheng L, Trussell J. The efficacy of IUDs for emergency contraception: a systematic review of 35 years of experience. Hum Reprod. 2012;27:1994–2000.
2. Glasier AF, Cameron ST, Fine PM, Logan SJ, Casale W, Van Horn J, Sogor L, Blithe DL, Scherrer B, Mathe H, Jaspart A, Ulmann A, Gainer E. Ulipristal acetate versus levonorgestrel for emergency contraception: a randomised non-inferiority trial and meta-analysis. Lancet. 2010;375:555–62.
3. Richardson AR, Maltz FN. Ulipristal acetate: review of the efficacy and safety of a newly approved agent for emergency contraception. Clinical therapeutics. 2012 Jan 31;34(1):24–36.