Natural Cycles App

Yes. You can use Natural Cycles if you have irregular periods. However Natural Cycles may be less suitable for you as it is more difficult for the algorithm to predict ovulation and therefore when you are likely to be fertile. Since the timing of ovulation can change with irregular cycles you may be given more red days i.e. days when you need to avoid sex or use other protection like condoms.

If you take the morning after pill, you can log this directly in the app. The Natural Cycles algorithm will then adapt to the changes in your cycle.

Natural Cycles is a type of fertility awareness method, which works by identifying your 'fertile window' and avoiding sex or using barrier methods such as condoms during this time. During your menstrual cycle your temperature rises and falls slightly which is due to the change in your body’s hormone levels. The Natural Cycles app uses an algorithm to analyse your temperature (and optional LH test results) and also takes into account other factors like sperm survival, temperature fluctuations, and cycle irregularities to identify ovulation. It then tells you if you are on a 'red day' or 'green day'.

To use Natural Cycles you need to pay for a subscription, download the app and buy a two decimal basal thermometer. You will need to measure your temperature under your tongue every morning – measuring before you get out of bed at roughly the same time every day and after a similar amount of sleep. You enter this data along with your menstrual cycle data, into the app. You will need to use protection like condoms or abstain from sex on red days. The number of green days will increase as the algorithm gets to know your menstrual cycle, and it can take around three months of using Natural Cycles for the algorithm to be effective. Check out the Natural Cycles website for further information.

There are no medical risks when using Natural Cycles. The only thing that can go wrong is that it leads to an unexpected pregnancy. Lots of factors (illness, lifestyle, stress or travel) may make fertility indicators harder to interpret or you may forget to take your temperature or input your menstrual cycle data into the app. You may also accidentally have sex or not use protection on a red day. If this happens you may need to use emergency contraception. When not using condoms you are also not protected from STIs.