Start with the first day of bleeding
Cycle day 1 is the first day of menstrual bleeding. If spotting is difficult to distinguish from a period or the bleeding is unusual for you, record the date and pattern and ask a clinician when needed.
When you log a start in MiniCycle, the app initially fills an end date using the current period-length setting. Correct that end date when the actual last day is different.
How to count cycle length
Cycle length is counted from the first day of one period to the first day of the next, including the bleeding days.
Two start dates give one cycle interval. Several months of dates are more useful for seeing a typical range and changes than a single interval.
Twenty-eight days is not a rule
Major health sources describe typical cycle ranges rather than requiring exactly 28 days, and their cutoffs differ slightly.
An app-based study also found wide variation, but its Natural Cycles users are not representative of everyone who menstruates. Use research averages as context, not a target for your body.
What else to record
Flow, pain, bleeding between periods, clots, mood changes, and medication can be useful details for a medical appointment.
Illness, sleep or schedule changes, exercise, and nutrition may provide context, but a note cannot establish that one event caused a cycle change.
What early predictions use
With no usable record, MiniCycle starts from 29 days for cycle length and 5 days for period length. These are defaults, not personal measurements.
The app uses up to 12 recent start dates and a median-based interval estimate. With at least 10 intervals it removes one shortest and one longest value. More records still cannot guarantee the next cycle. Data stays on the device by default; enabling iCloud Sync stores a copy in your iCloud through Apple CloudKit.
Limits of tracking and when to seek advice
Tracking can show dates and symptoms but cannot diagnose a cause. Estimated ovulation and fertile-window dates are not contraception or pregnancy confirmation.
Seek medical advice if periods stop for more than 90 days when pregnancy is not the reason, a regular pattern changes, bleeding lasts longer than seven days, bleeding occurs between periods, pain is severe, or the change concerns you. Very heavy bleeding with dizziness, shortness of breath, chest pain, or other urgent symptoms needs prompt assessment.
MiniCycle for iPhone
Try MiniCycle
MiniCycle is built for a clean iPhone period calendar, local records, simple statistics, and a home screen widget.
MiniCycle editorial