Timing contractions: what the 5-1-1 rule actually means

Somewhere around the middle of the night, someone will ask "how far apart are they?" and the honest answer will be "I'm not sure, maybe five minutes?" That uncertainty is the entire problem a contraction timer solves — not the maths, but the fact that nobody can do the maths while it is happening.

The two numbers that matter

Hospitals and midwives ask about frequency and duration, and people mix them up under pressure.

• Frequency is measured from the start of one contraction to the start of the next — not from the end of one to the beginning of the next. Getting this wrong makes contractions look further apart than they are.
• Duration is how long a single contraction lasts, start to finish.

A third thing matters and cannot be timed: intensity. Contractions that you can talk through are different from contractions that stop you mid-sentence, even at identical timings.

The 5-1-1 rule

The guidance most commonly given for a first birth is 5-1-1:

• Contractions 5 minutes apart
• Each lasting 1 minute
• Sustained for 1 hour

Some hospitals use 4-1-1 or 3-1-1, and second babies often come with different advice because labour tends to move faster. Whatever your midwife or hospital told you overrides the general rule — they know your pregnancy and the general rule does not.

The pattern matters more than any single contraction. Three contractions five minutes apart is not the same as an hour of them, which is why the rule has a third number.

What early labour actually looks like

Early contractions are usually irregular: eight minutes, then twelve, then six. That irregularity is normal and it is also why timing by memory fails — the brain remembers the short gaps and forgets the long ones, so labour feels more advanced than it is.

Braxton Hicks contractions add to the confusion. They tend to be irregular, do not get closer together, and often ease off if you change position or drink water. Real labour contractions get longer, stronger and closer together and do not stop when you move.

Why a phone app rather than a notes app

At 3 a.m., with a contraction starting, nobody wants to unlock a phone, find an app, read a menu and choose an option. What is needed is one button, big enough to hit without looking, that starts and stops. Everything else — the averages, the pattern, whether 5-1-1 has been met — should be worked out afterwards, by the app, not by a person in labour.

What Waves does

Waves is that one button. Tap when a contraction starts, tap when it ends, and it does the rest: frequency measured correctly from start to start, duration, rolling averages, and a clear signal when the 5-1-1 pattern has actually been sustained for an hour rather than just occurring once.

It also counts kicks, using the same one-tap approach, for the daily fetal movement counts many midwives ask for in the third trimester.

The log exports, so at the hospital you can show the timings instead of reconstructing them from memory. There is no account and nothing is uploaded — it works in a car park with no signal, which is roughly where it tends to get used.

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