Standard Fertility Method
Using a scientific method to measure the length of your monthly cycle, Cycles is most accurate when calculating cycles that fall between 26 and 32 days long. This method marks days 8 through 19 as fertile.
As long as your cycle is within 26 to 32 days, this method will maintain its accuracy regardless of when your ovulation day actually falls.
Logging your Cervical Mucus Quality will also have an impact on your fertility dates in Cycles. Learn more about this here.
For shorter or longer cycles, fertility dates are calculated based on your ovulation day. Cycles does this by marking 5 days before and 2 days after your ovulation as fertile. This is because, under optimal conditions, sperm can stay alive inside a woman for up to 5 days. It’s been reported that women can conceive up to 2 days after ovulation.
If you consistently log your BBT, CMQ or ovulation tests, Cycles will check if you'd like to switch to the Ovulation Method for improved fertility accuracy.
Please note: your ovulation day may change based on outside factors, such as stress or sickness. Also, Cycles is not intended to use as a means to prevent pregnancy in any way.
Looking to switch your ovulation method?
Simply tap Settings > Fertility Tracking > Toggle off Automatic Selection and chose the option that best suits your needs.