What it means
Your uterus is a muscle, and it contracts. During menstruation the contractions are stronger and more painful because of chemical messengers called prostaglandins — which also cause the cramping back pain, nausea, loose stools and headache many people get.
That mechanism matters, because it explains why anti-inflammatory painkillers help: they work by reducing prostaglandins. Paracetamol does not, which is why it is usually the weaker option for period pain.
What can vary
Some pain is expected. Cramping in the lower abdomen during the first day or two of bleeding, sometimes spreading to the lower back or thighs, is common and treatable.
What is not expected is pain that:
- Stops you doing normal activities regularly
- Does not respond to ordinary painkillers
- Is getting worse over time
- Is one-sided rather than central
- Happens between periods
- Comes with heavy bleeding, fever, or pain during sex
Severe period pain is not a thing you must endure. The most common causes — endometriosis and adenomyosis — are treatable, and are frequently missed for years because people assume the pain is normal.
Possible explanations
A clinician considers: primary dysmenorrhoea, which is common and responds well to anti-inflammatories; secondary dysmenorrhoea from endometriosis, adenomyosis or fibroids; and less commonly infection or other conditions.
The pattern of when the pain happens is often more diagnostic than how bad it is.
Warning signs
Emergency: pain with fever, fainting, or severe heavy bleeding; severe pelvic pain that is sudden and worsening.
Prompt: pain not responding to painkillers, pain getting worse, one-sided pain, pain between periods, or pain with heavy bleeding or sex.
What to do next
Track your pain honestly — how many days, how bad out of ten, and whether ordinary painkillers work. That record changes what a clinician can do.
If pain is disabling, say that plainly. “It makes me miss school two days a month” gets a different response than “it’s quite bad”.
Ask specifically about anti-inflammatory options rather than accepting whatever is offered.
Self-care
These genuinely work, in rough order of evidence:
- Heat. A hot water bottle or heat pad. This is not a placebo — heat relaxes muscle and reduces pain signalling.
- NSAIDs such as ibuprofen or naproxen, taken at the first sign and as directed. These work on prostaglandins directly. Not suitable for everyone; check the packet and with a pharmacist if unsure.
- Movement. Walking, stretching and yoga reduce pain for many people.
- TENS units and heat patches.
- Sleep, and avoiding known triggers if you notice a pattern.
What does not reliably help: herbal remedies sold for period pain, “detox” products, and anything claiming to cure cramps permanently.
When to seek help
Routine: if periods are painful but manageable.
Prompt: if pain regularly stops you functioning, does not respond to anti-inflammatories, is one-sided, or is worsening.
Emergency: pain with fever, fainting, or severe heavy bleeding.
How to talk about it
“My period pain stops me going to school. Painkillers only take the edge off.”
“It’s mainly on one side and it hurts when I’m on my period.”
“It’s getting worse each cycle.”
Specificity is what gets you assessed. “It hurts” leads to reassurance; “it stops me swimming for two days a month and ibuprofen takes it from a 9 to a 5” leads to a plan.
Related articles
Sources
Public sources are linked so you can read the detail rather than take this site’s word for it. None of this has yet been reviewed by a qualified clinician — see how we handle medical review.
References
Where this comes from
Linked so you can check it against a recognised public health source rather than take this site's word for it.
- Period pain — NHS NHS (opens in a new tab)
- The menstrual cycle — RCOG Royal College of Obstetricians and Gynaecologists (opens in a new tab)
These are public sources from recognised health organisations, linked so you can read the detail rather than take this site's word for it. Reading them does not tell you whether any of it applies to you, and none of these articles has yet been reviewed by a qualified clinician. How we handle sourcing and review.