The short answer
Rythena pauses its fertility estimate layer during an ongoing tracked period or recorded menstruation. This avoids conflicting UI states; it is a product safety rule, not a conclusion that pregnancy cannot occur.
Seeing fertility estimates during a period can be confusing when the screen's most relevant fact is that you are currently bleeding. The app should not make you decide which of two competing messages to believe.
The upcoming Rythena app prioritizes the ongoing period-day counter and recorded menstruation. Its fertility layer can pause rather than display a conflicting “possibly fertile” state over that information.
A paused layer has a narrow meaning
It means the app is not presenting this calendar estimate in the current saved state. It does not mean that the app has measured your hormones, established that ovulation cannot happen or ruled out pregnancy.
That distinction is essential. Rythena's estimates must not be used as birth control, whether the layer is visible or absent. An unmarked calendar date is not a clinically verified safe day.
Check the period episode first
If you used Start period, inspect whether the episode is still ongoing. The day counter should continue until you record an actual last day. It should not disappear merely because you skipped daily logging.
If the period ended and you forgot to save the end, use End period with the correct last day. Do not end an episode solely to force fertility information to reappear. The saved state should describe what happened, not what you want the interface to display.
Recorded daily bleeding is a separate check
You can have individual recorded menstruation observations as well as an explicitly tracked episode. The app needs to consider these records when deciding what it can show.
If something appears contradictory, inspect the selected day's observations and any episode boundaries. Correct an actual mistake at its source rather than repeatedly changing the fertility toggle. A toggle cannot repair a wrong date.
Other reasons can still withhold the estimate
After an episode ends, the layer does not necessarily become eligible immediately. The calculation also considers the chosen cycle basis, available history, variability, current context and whether the estimated window has already passed.
Read the unavailable-state explanation. Manual mode is a chosen input basis, not a command to ignore all other rules. Early provisional visual estimates also have different requirements from reminder eligibility.
Keep the daily screen useful
While fertility is paused, you can still record a mood, note a symptom and review the period counter. If those are the things you came to do, there is no need to complete more setup merely to fill an empty calendar layer.
The goal is a clear answer for the current task. A well-labelled unavailable estimate can be more useful than a marker that suggests a certainty the app does not have.
See the ovulation-calendar guide for the broader explanation, the ongoing-period counter for episode boundaries and simple period tracking for a lighter routine.
Sources & product basis
Product steps checked against Rythena’s upcoming iOS implementation and listing. Examples are illustrative. AI-assisted writing; no clinical sign-off. Sources checked 2 November 2026. Editorial approach and corrections.
Make it a smaller routine.
See the app, check what stays free and choose the tools that help you.