How long do period cramps last, and how bad can they get?
The short answer
Period cramps usually begin just before or as bleeding starts, are worst in the first 24 hours, and last 1 to 3 days. ACOG describes typical pain as starting a day or two before the period and lasting 12 to 72 hours. Cramps that last the whole period, start a week early, or keep you off school or work are worth a doctor’s visit.
When cramps start
The womb squeezes to shed its lining, and the chemicals that drive the squeezing (prostaglandins) are highest right at the start of the period. So cramps most often start:
- the day before bleeding, or
- the first morning of the period.
Cramps that begin a week or more before the period are more likely premenstrual symptoms or, if they are strong, something like endometriosis. See signs your period is coming.
How long after cramps does the period start?
If cramps are the kind that come right before a period, bleeding usually follows within a few hours to a day. If you have had cramps for several days with no bleeding, think about: a late period (why is my period late), ovulation pain (a one-sided twinge mid-cycle), a stomach bug, or early pregnancy if you could be pregnant.
How bad can cramps get?
Most people describe period cramps as a dull, squeezing ache that comes in waves, strong enough to notice but not enough to stop the day. For some, cramps are sharp, spread to the back and thighs, and come with nausea, diarrhoea, headache or dizziness. ACOG and the NHS both say pain this strong is common but not something to just put up with: it responds well to treatment, and it can be a sign of a condition such as endometriosis, adenomyosis or fibroids.
A useful test is whether painkillers work. Primary period pain (the ordinary kind) usually eases with ibuprofen or similar. Pain that doesn’t respond, or is getting worse year by year, needs a check.
What helps
- Anti-inflammatory painkillers such as ibuprofen, started as soon as cramps begin (ask a pharmacist if you can take them; some people can’t).
- Heat: a hot-water bottle or heat patch on the belly or back.
- Gentle movement: walking or stretching often eases cramps more than lying still.
- Hormonal contraception reduces cramps for many people and is a common treatment for severe pain.
- Rest, water, and easing up on caffeine help some people.
When to see a doctor
- Pain that stops you going to school or work, or isn’t helped by painkillers
- Cramps that last the whole period or more than 3 days of real pain
- Pain that started being bad after years of mild periods, or is getting worse
- Pain between periods, during sex, or when going to the toilet
- Heavy bleeding with the pain (soaking a pad every 1 to 2 hours)
- Pain with fever, or sudden severe pain on one side
Track the pattern
Noting how many days you had cramps, how strong they were, and whether painkillers helped tells a doctor far more than “they’re bad”. Over a few months it also shows whether things are stable or getting worse. Cycella logs which days you had pain, with the dates, in a few taps with no account, and keeps it on your phone; the app is free on Google Play for Android.
Try the Next period calculator, or see Cycella in Nepal. Cycella is a free, private Android period tracker, now on Google Play.
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