Question 1

Can this tool tell me when to go to the hospital?

Accepted Answer

[Important Notice: This tool is strictly a calculation aid and does NOT constitute medical judgment or clinical advice]

This application objectively tracks your timestamps and computes frequency intervals, durations, and regularity trends purely mathematically.

① Every labor progression is unique. When to go to the hospital or birth center depends on whether this is your first baby, your specific clinical background, and your OB-GYN or midwife's customized instructions.

② If you experience water breaking, persistent bright-red bleeding, significantly reduced fetal movement, intolerable severe pain, or any symptom that concerns you, please contact your maternity unit or proceed to the hospital immediately without waiting for numbers in this tool.

Question 2

How does this tool calculate "how often" and "how long" contractions are?

Accepted Answer

Each time you press Start and then Stop, the tool records the start and end time of one contraction:

① Duration (how long): end time minus start time.

② Frequency (how often): from the start of one contraction to the start of the next. This is the standard method taught in prenatal classes, not measured from the end of the previous one.

The numbers shown are the median of the most recent 5 contractions. The median is used instead of the average because a single missed or accidental press would skew the average, while the median stays stable.

Question 3

How is "regular" determined, and how is "how long this pattern has lasted" calculated?

Accepted Answer

[Regularity] The tool checks how consistent the 4 intervals between the latest 5 contractions are (coefficient of variation = standard deviation ÷ mean): within 20% is "Regular", within 35% is "Fairly regular", above that is "Irregular".

[Pattern duration] Starting from the latest contraction and walking backward, a contraction belongs to the same pattern if its interval is within ±25% (at least ±1.5 minutes) and its duration within ±30% (at least ±15 seconds) of the current values. One mismatch in between (such as a missed press) is tolerated; two in a row ends the scan. The earliest matching contraction marks the start of the pattern.

[Trend] The latest 5 contractions are compared with the 5 before them. A trend such as "Getting closer" or "Getting longer" is only shown when the change exceeds 15%.

Question 4

Why use the latest 5 contractions? Why are there no numbers at first?

Accepted Answer

Prenatal education commonly advises timing 5 to 6 contractions in a row before judging the pattern, so this tool uses the latest 5 as its calculation window.

Preliminary numbers appear after 3 contractions (2 intervals), marked as "Collecting data"; they become more stable after 5.

If two contractions are more than 30 minutes apart, the tool treats it as a break and starts counting again.

Question 5

What if I pressed by mistake or forgot to press Stop?

Accepted Answer

① While timing, press "Cancel this one" to discard the current record.

② Records shorter than 10 seconds are marked as "Possible mis-press" and records longer than 3 minutes as "Possibly forgot to stop". Neither is included in the calculations.

③ Every record in the list below can be deleted individually.

Question 6

Where is my data stored? Is it uploaded anywhere?

Accepted Answer

Nothing is uploaded. All records are stored only in the browser on this phone or computer (the browser's local storage, localStorage). This tool has no server database, requires no login, and never sends any contraction data anywhere.

This means you will not see previous records on another phone, another browser, or in private browsing mode. To keep your partner informed, use "Copy summary" and paste it into a messaging app.

Question 7

How long are records kept? Can I delete them manually?

Accepted Answer

This tool only looks at changes within the last 6 hours. Records older than 6 hours are deleted automatically and are never kept long term.

You can also press "Clear all records" at any time to delete everything immediately. Clearing the site data in your browser will delete them as well.

Contraction Timer

Current Status

Phone Cheat Sheet (Quick Script)

6-Hour Trend

Contraction Log

Frequently Asked Questions7 Q&As