Period tracker without predictions: logging vs. forecasting

When you look for a period app, most of them show the same thing on the home screen: “Your period is due in 4 days.” That date sounds certain, but it is really a prediction. Some apps don't predict at all; they only log the days you actually have. In this article we explain the difference between the two approaches, why predictions don't always match and who might prefer record-based tracking.

What does a “prediction” mean in period apps?

An app that predicts takes the period start dates you enter and works out an average cycle length. It then adds that average forward to place your next period on the calendar, and sometimes dates such as an ovulation day or a “fertile window” too.

At heart this is a calendar calculation. The app doesn't know what is happening in your body; it only looks at the dates you logged in the past. If your cycle is the same length every month, the prediction may come close. If your cycle varies, the prediction shifts as well.

That doesn't make predictions a problem; for many people they are a handy reminder. What matters is knowing what the date on the screen means. A future date on the calendar says “your past records give this average”; it doesn't say “your period will definitely start on this day.” Once you know this, you won't blame yourself or worry straight away if your period doesn't start on the predicted day.

Why aren't predictions always right?

According to the NHS, the UK's health service, a cycle is usually around 28 days, but it commonly varies between 21 and 35 days. So “normal” isn't a single number, it's a range. The same person's cycle can also move by a few days from month to month.

The NHS also lists some things that can affect your pattern:

• Stress and anxiety
• Significant weight loss or weight gain
• Very intense exercise
• Some hormonal contraception methods
• Times of transition such as puberty and the years approaching menopause

An average can't see these factors. So when a predicted date comes and goes, or your period starts earlier than expected, it's your own body that tells the truth, not the prediction. For some people a date that looks “late” on the calendar can also cause needless worry. Especially if your pattern has only just started to change, seeing alerts like “late” or “early” on the screen can raise more questions than it answers.

What does an app without predictions offer?

A record-based app only keeps the days you really lived. There are no future dates on the calendar; you see whatever you logged in your history. Days you didn't log stay empty, and the app doesn't fill the gaps with guesses.

Here is what this approach gives you:

• A real history: what you show your doctor isn't a calculation but the dates you logged.
• Less false certainty: the calendar doesn't wait for a date, so you never see a “late” label.
• Seeing your own pattern: after a few months of records, you can read your cycle lengths and period lengths yourself.
• Noticing changes: when something changes in your pattern, you see it clearly in your records.

Record-based tracking asks for a little more attention: the app won't tell you when your next period is, you get a rough idea by looking at your own records. For many people this means looking at the calendar more calmly. As your records grow, you see your own average and how much it varies; this is more personal than a prediction, because it comes straight from the days you lived.

We also covered what else to look at when choosing an app in 6 things to check when choosing a health app.

Who might prefer record-based tracking?

Neither apps that predict nor apps that don't are right for everyone; you choose based on what you need. Record-based tracking can be especially useful if:

• your cycle often changes and predictions mislead you
• you want a simple, accurate history to take to your doctor
• predicted dates on the calendar make you anxious
• your pattern is changing because you are in a time of transition in your life

One point needs to be said separately: no app's prediction is enough on its own for contraception. The NHS recommends learning fertility awareness methods from a trained expert and does not officially recommend any app for this purpose. If you are thinking of relying on cycle tracking to avoid or to plan a pregnancy, be sure to talk to your doctor about it.

Reading your own records: 4 steps

You can learn a lot about your cycle without predictions. You don't need complicated maths for it:

1. Log the start day. Note the first day of bleeding; your cycle is counted from this day.
2. Count the length. Write down how many days your period lasts. According to the NHS, a period usually lasts between 2 and 7 days.
3. Note the gap. Work out how many days pass from one period start to the next. We showed how to do this step by step in how to track your period and work out your cycle length.
4. Talk about changes. If your pattern changes, your period lasts longer than 7 days or you bleed between periods, take your records and talk to your doctor.

If you're looking for a plan for the first months, starting cycle tracking: a simple plan for your first 3 months can be a good place to begin. If something frightens you, such as severe pain or very heavy bleeding, see a doctor without waiting; in an emergency, call your local emergency number.

Cycle tracking without predictions in Oveluni

Oveluni is record-based. In the Cycle area that opens in the Woman profile, you log the days you have with Period days in the Quick add menu; these days appear in the Calendar. In the app's own words: “Only recorded history is available. There are no fertility, ovulation or pregnancy predictions.”

On the Insights screen you can see your recorded period lengths and place two equal periods side by side with period comparison. “These summaries reflect your entries. They do not diagnose conditions or predict future cycles.” If you'd like to take it to your doctor, you can create a PDF report. You can find what the women's profile includes on the Women's Profile page. Oveluni is coming soon to the App Store.

Sources

1. NHS: Periods and cycle length
2. NHS: Irregular periods and possible causes
3. NHS: Natural family planning and fertility awareness