Frequently Asked Questions

Read up on the questions we get asked the most.

To use the app you will need a two decimal basal thermometer. It’s more sensitive than a regular fever thermometer, as it shows two decimals. The good news is that you get one included when you sign up for our ‘Annual subscription’.
The app works effectively from the beginning and it takes around 1-3 cycles for the app to get to know you. That’s why you might have more red days in the beginning. Be patient and continue to measure.
Your temperature will deviate if you feel sick, hungover or have slept more less (±2 hours) than usual you. The app will often detect a deviating temperature automatically but if you have these symptoms - you can select this manually in the app by tapping ‘Deviating temp.’. The app will still work effectively and takes temperature fluctuations into account, but you might get a few more red days.
On average you get around 10 red days a cycle. You and your partner should be comfortable with abstaining or using protection like a condom on these days to effectively prevent a pregnancy.
It depends on the type of contraception you are using. If you are using NON-hormonal contraception (condoms, copper IUD etc.), you can get started right away. Hormonal contraception affects your cycle and temperature, so you cannot start using Natural Cycles until you have come off it. You will have to wait approx. a week to get started (read more on Cyclerpedia). The exception for this is the hormonal IUD, which as well as the copper IUD can be used in combination with Natural Cycles. After coming off hormonal contraception cycle irregularities are quite common.
We recommend the app to women between the ages of 20-40 who are in a stable relationship, comfortable with using protection (condoms) on red days and don’t mind measuring their temperature in the morning. The better it suits your lifestyle, the more you get out of using the app. You will soon see that a little habit like measuring your temperature every morning will allow you to get to know your body and enjoy a method of contraception with no side-effects.
It’s quite common to have irregularities, especially if you have recently stopped using hormonal contraception. The Natural Cycles algorithm takes factors such as cycle regularity and temperature fluctuations into account when analysing your unique cycle and calculating predictions. It will still be effective, but you might experience more red days. That’s why it may not be suited as a contraceptive for women with very irregular cycles. However, by tracking your cycle you will have a complete overview of how your unique cycle works and may even find out what is causing these irregularities by taking note of symptoms or discussing it with your doctor.
Once you have ordered your thermometer you can expect the following shipping times: Up to 6 days for Sweden and the UK. Up to 11 days for the rest of Europe and the US (except Alaska and Hawaii). Up to 22 days for Brazil. Up to 30 days for the rest of the world. You can order your thermometer in Celsius or Fahrenheit. We ship thermometers all around the world except to the countries of Mexico, Argentina, Colombia, South Africa, Saudi Arabia, United Emirates, and Chile. You can, however, get your own two decimal certified thermometer and use it in combination with the Natural Cycles app.
Yes. Clinical studies have shown that Natural Cycles’ effectiveness as a contraceptive method is comparable to other conventional methods. During one year, 1 woman out of 100 gets pregnant due to a falsely attributed green day or condom failure on red days. 7 women out of 100 get pregnant during one year due to all possible reasons (e.g. having intercourse without protection on red days or failure of the contraceptive method used on red days).
During your menstrual cycle your temperature rises and falls slightly which is due to the change in your body's hormone levels. So the Natural Cycles algorithm analyses your temperature and also takes other factors like sperm survival, temperature fluctuations, past cycles and cycle irregularities into account - to determine whether you are fertile or not and calculate your red and green days. Optional ovulation (LH) tests also help the app to pin-point your ovulation and determine these days.
Although Natural Cycles and Natural Family Planning show similarities, the method is not the same, which is why Natural Cycles has a different Pearl Index. Natural Cycles only takes objective measurements into account such as temperature, LH (ovulation) tests, sperm survival etc. and adapts to your unique cycle. There is no extensive studying, paperwork or second guessing - the app does the work for you and tells you exactly when to use protection, so you can learn about your body and cycle along the way.
Natural Cycles is an app you can download from the App Store or on Google Play. You can start using the app by purchasing a ‘Monthly or Annual subscription’. The Annual subscription includes a two decimal basal thermometer, which you will need to be able to use Natural Cycles. It’s more sensitive than a regular fever thermometer. Both subscriptions will renew automatically unless cancelled. You can cancel, renew or change payment type at any stage in your ‘Profile’ within the app. If you have purchased through In-app purchases go to your iTunes settings. Please note that with the ‘Annual subscription’ payment and you will be charged in full for 12 months of access to Natural Cycles.
We are extremely proud to say that our extensive research into women’s health, our product design, the precision of the algorithm and the company’s quality assurance system have all led to this certification. Without the immense support and genuine love of the product from thousands of Cyclers throughout the years - we wouldn’t have gotten to where we are today.