AIVELA Cycle Tracking begins with something only you can confirm: when your period actually started. It combines that record with your cycle history, nighttime temperature trends, and other suitable physiological information to estimate your current phase and the timing of your next period.

The central rule is simple: your confirmed record is a fact; every future date and phase remains an estimate.

A changing date does not rewrite what you lived

If the next expected period shifts, first check whether you recently confirmed or corrected a record. Your actual history and the future estimate have different roles. That distinction allows the view to become more relevant while keeping your own report visible, rather than presenting every future date as certain.

The starting point: a confirmed period start

During setup, AIVELA asks for your most recent known period and typical cycle information. This supports an initial estimate, so Cycle Tracking can be useful before a deeply personalized temperature pattern has formed.

After setup, each new period start you confirm anchors a new cycle and creates Cycle Day 1. It also gives the prediction system a new real-world reference point.

A predicted start never confirms itself. If the expected date passes without a new log, the App may move into an estimated display cycle so you can still see a useful current view. That display is labeled as prediction-based and does not become part of your confirmed history, cycle-length baseline, or period record.

Start and end dates do different jobs

The first day of a confirmed period defines the start of a new cycle and is the main user-provided input for refreshing future predictions.

The end date you confirm helps AIVELA describe period length, improve your personal period-length baseline, complete cycle history, and draw the Period portion of the Cycle Ring. It does not create a new cycle.

If you have not confirmed the end, AIVELA can estimate it for the current display and ask whether your period has ended. That estimate keeps the Cycle Ring usable, but it never becomes a confirmed end unless you say so.

The useful signal is a pattern, not one warm night

Across many natural menstrual cycles, temperature tends to follow a two-part pattern: generally lower through much of the follicular phase and higher during the luteal phase after ovulation. The shift is influenced by changing hormones, especially the rise in progesterone after ovulation.

AIVELA uses nighttime skin-temperature trends because repeated overnight conditions can provide a more consistent view than scattered daytime readings. The system learns how the pattern appears for you, rather than comparing one absolute temperature with a universal target.

One warm or cool night is not enough to confirm a phase. Skin temperature can also respond to room conditions, illness, alcohol, sleep disruption, travel, and other forms of acute strain. Cycle Tracking therefore considers the developing pattern together with confirmed cycle history and other suitable data.

Skin temperature is not core body temperature, and the ring is not a clinical thermometer.

Useful early, more personal with consistent wear

Initial predictions are available from the information you enter during setup. As overnight data accumulates, AIVELA gains more opportunity to recognize your recurring temperature pattern and adapt future estimates.

Consistent overnight wear and accurate confirmed records help the personal picture develop. There is no single date after which an estimate becomes certain.

Two habits matter most:

1. Wear the ring consistently overnight.
2. Confirm each actual period start, including a corrected date when necessary.

Logging an end date helps your period history, while the confirmed start keeps future cycle timing aligned.

How AIVELA maps the Cycle Ring

When the normal Cycle Tracking experience is available, the current display uses four phase labels:

• Period , based first on the start and end dates you confirm, with an estimated end only when needed for display;
• Follicular , the time after the displayed Period phase and before the estimated Ovulatory phase;
• Ovulatory , a short estimated phase around the system's predicted ovulation timing;
• Luteal , the estimated phase after Ovulatory and before the next expected period.

Confirmed period information takes priority when it conflicts with a prediction. AIVELA does not move a predicted Ovulatory phase to make the picture look neater, and it does not treat the phase as confirmation that ovulation occurred.

The consumer view shows the Ovulatory Phase, not a specific predicted ovulation date. This feature does not calculate or display a fertile window.

An estimate can change while your history stays yours

New confirmed period records or suitable overnight information can change a future estimate. Read the current labels to distinguish what you confirmed from what is predicted.

If a prediction is unavailable, synchronize and check your latest actual record. You do not need to invent a date to make the display look complete.

A changing prediction is not necessarily an error

Prediction dates may shift because cycles themselves vary. They may also change after you add or correct a period start, or after newer temperature and physiological information becomes available.

Look for the label:

• a confirmed date came from a record you saved;
• an estimated date or phase came from the current prediction;
• an unavailable prediction means AIVELA does not have enough current information to extend the view responsibly.

That distinction is more important than making every date appear certain.

What the model cannot establish

Temperature patterns can support cycle-phase estimation, but they cannot by themselves confirm ovulation, fertility, pregnancy, a hormone disorder, or the cause of an irregular cycle. Not everyone shows the same temperature pattern, and hormonal medication or major reproductive changes can make ordinary phase assumptions less useful.

AIVELA may limit or pause phase predictions in those situations rather than present false confidence. Cycle Tracking is for consumer wellness and body awareness, not contraception, conception planning, or medical diagnosis.

The goal is not to turn a changing cycle into a fixed calendar. It is to make the estimate more personal while keeping uncertainty visible.

Related reading

• What Is AIVELA Cycle Tracking?
• What Skin Temperature Can, and Cannot, Tell You
• How AIVELA Builds Your Personal Baseline
• Data Quality, Gaps, and Estimated Results