How to time contractions, and what your provider means by 5-1-1

Every contraction gives you two measurements:

• Duration — how long one contraction lasts, from the moment it starts to the moment it eases off completely.
• Frequency — how far apart contractions are, measured from the start of one contraction to the start of the next. Not from the end of one to the start of the next; that gap is the rest period.

Mixing these up is the most common mistake, and it makes contractions look further apart than they are. If a contraction starts at 10:00 and lasts a minute, and the next starts at 10:05, they are five minutes apart.

You need a clock with a second hand or a phone stopwatch, and something to write on. Your partner can do the writing while you breathe through each one.

1. 1When a contraction starts, note the time to the second or as close as you can.
2. 2When it ends, note the time again.
3. 3Repeat for each contraction.
4. 4After several contractions, work out the duration of each (end minus start) and the frequency (this start minus the previous start).

A few rows might look like this: start 10:00:00, end 10:00:55; start 10:06:10, end 10:07:00; start 10:11:30, end 10:12:30. That is roughly every five to six minutes, lasting about a minute each.

Timing a single pair of contractions tells you very little. Most providers want to know the pattern over the last hour or so: are they getting longer, stronger and closer together?

Many providers give a simple rule for when to call or come in during early labour. Two common ones are:

• 5-1-1: contractions about 5 minutes apart, each lasting about 1 minute, for at least 1 hour.
• 4-1-1: contractions about 4 minutes apart, each lasting about 1 minute, for at least 1 hour.

These are not universal. Your provider may give you a different rule depending on how far you live from the hospital, whether this is your first baby, and your own medical history. People who have given birth before are often told to come in earlier, because later labours can move faster. If you were not given a rule, ask at your next appointment, and write the answer somewhere you will find it.

Practice contractions (often called Braxton Hicks) can start weeks before labour. They tend to be irregular, do not steadily get closer together, and often ease when you change position, rest, or have a drink of water.

Labour contractions usually follow a pattern: they become longer, stronger and closer together over time, and keep coming whatever you do. Timing is exactly how you tell the difference, which is why it helps to start writing them down early rather than trying to remember.

If you cannot tell, call your provider. That is what they are there for, and they would rather hear from you.

Most maternity units ask you to call straight away, whatever your contractions are doing, if any of the following happens. Your own provider's list comes first; this is the general idea:

• Your waters break, or you think they might have, especially if the fluid is green, brown or smells unusual.
• You have vaginal bleeding.
• The baby is moving less than usual.
• You have constant, severe pain rather than pain that comes and goes.
• You have a fever, a bad headache, changes in your vision, or you feel very unwell.
• You are having regular contractions before 37 weeks.

In an emergency, call your local emergency number.

• Let the person in labour simply say 'now' at the start and end; you do the writing.
• Keep the record in one place and keep going even when you think you see a pattern. The phone call to the hospital goes better when you can read out the last hour.
• Note anything else relevant next to the times: waters breaking, bleeding, the baby's movements.
• Have the hospital bag, documents and the number to call ready before labour starts.

When you add a baby to Baton with a due date, the app becomes a contraction timer: one large button to tap when a contraction starts and again when it ends. Baton works out the length of each one, the time between them, and a summary of the last hour — how many, how far apart and how long — so nobody has to do arithmetic between contractions.

The Start/Stop button is also on the Lock Screen and the Dynamic Island. If your provider gave you a 5-1-1 or 4-1-1 rule, you can choose it (it is off by default) and Baton tells you when your last hour matches it — and always tells you to follow your doctor's or midwife's instructions. You can share a summary as a message or PDF, and your partner can time contractions on their own phone through iCloud.

Baton only times contractions; it is not medical advice. The contraction timer is free, and Baton never shows a paid offer during labour. When the baby arrives, the same profile becomes the baby log.