Generally speaking, it takes the algorithm 1-3 cycles to get to know your cycle. Depending on the mode that you are using, your data may be affected differently:
For NC° Birth Control
NC° Birth Control is effective from day one, and this is why you should expect more red days until the algorithm has gotten to know your unique cycle. The app will only give you green days if it has enough data to do so, either by confirming that you have ovulated or that you are unlikely to do so within five days (due to sperm survival).
For NC° Plan Pregnancy
For those using NC° Plan Pregnancy, it's normal to get many brown days in the beginning. You will be given brown days when the algorithm needs more data to be able to identify the fertility status for that day. For instance, towards the beginning of a cycle, you may get brown days instead of green ‘Not fertile’ days when the algorithm is unsure whether or not you’re approaching your fertile window.
What can affect how long it takes the algorithm to get to know you?
Recently quitting hormonal birth control
If you have recently come off hormonal birth control, the first ovulation may only occur after a couple of months – this is normal and nothing to worry about. If you find yourself in that situation, be patient, and keep measuring. You will get more red days (for NC° Birth Control) or brown days (for NC° Plan Pregnancy) in the beginning, but these will decrease with each ovulatory cycle as the app gathers more data on you.
You can read more about what to expect after quitting hormones here.
Certain medical conditions
If you have a medical condition such as PCOS, endometriosis, or hypothyroidism, you can still use the app. It may however take longer for the algorithm to get to know your cycle. Learn more here.
If you have irregular cycles, the algorithm may also need more time to understand your cycle, and you may get more red days than average. A cycle is considered irregular if it lasts less than 21 days or more than 35 days, and/or if the length varies greatly from one cycle to the next. Learn more here.
How will my predictions look as a new user?
In the beginning, you will be given more generalized predictions. As you move forward in your cycles and log more data, your predictions will adapt accordingly and will become more and more personalized.
How can I make sure that the algorithm gets to know my cycle as fast as possible?
The best way to ensure that the algorithm gets to know your unique cycle is to add data regularly into the app. The more data you add, the more personalized your experience will be!
Temperature data is the most important data that you can log, as it allows the algorithm to identify your fertile window. For this reason, you should make sure to log temperature data as often as possible (we recommend at least five days a week). That said, if you sometimes forget to measure your temperature, it will not affect Natural Cycles’ effectiveness as birth control. Less temperature data will make it harder for the algorithm to identify your fertile window, and as a result, you will get more red days (for NC° Birth Control) or brown days (for NC° Plan Pregnancy), which may reduce your satisfaction with the app.
It’s also very important to log period data; make sure that you select Period for each day that you experience period bleeding. Learn more here.
A bonus way for the algorithm to get to know you is to log LH test results, as it may help narrow down ovulation, but please keep in mind that LH tests are optional. Learn more here.