Period Pain: What Is Normal, What Is Not, and When to Ask Someone

Period pain is common, and the usual version has a shape: it starts around the first day, it eases as the bleeding goes on, and it lasts up to about three days. ACOG says more than half of women who menstruate have some pain for 1 to 2 days each month, and names the mechanism — prostaglandins made in the lining of the uterus, at their highest on the first day of a period and falling as bleeding continues, which is exactly why the worst of it is usually at the front. What is not that shape is worth an appointment: pain that gets worse over time, lasts longer than ordinary cramps, stops you doing your usual activities, or is severe and not touched by painkillers. Nothing on this page is a diagnosis, and the thresholds below are quoted from the NHS rather than invented here.

That is the whole answer. The rest of this page is what each half of it means, what a doctor is looking at when the second half applies, and how to turn a month of pain into something a five-minute appointment can actually use.

Why it hurts, and why day one is the worst of it

The NHS puts it plainly: period pain happens when your womb tightens during your period. It is often a normal part of the menstrual cycle, it usually lasts up to 3 days, and it sometimes spreads to the back and thighs. The NICHD lists abdominal or pelvic cramping and lower back pain among the ordinary symptoms of menstruation, alongside bloating, sore breasts, food cravings, mood swings, headache and fatigue.

ACOG adds the reason for the timing. Primary dysmenorrhoea — pain with no underlying disorder behind it — is caused by prostaglandins made in the lining of the uterus. Their level is high on the first day of a period and goes down as bleeding continues, which is why the pain tends to lessen after the first few days.

That is a genuinely reassuring piece of physiology, and it is worth knowing for a practical reason as well as a comforting one: pain that does the opposite, building through a period rather than fading, is not following the ordinary pattern. What day one is and why it is counted the way it is sits in the menstrual phase explained.

The two shapes, on the four things you get asked

The right-hand column is not a diagnosis and does not mean anything is wrong. It is the description that makes a clinician ask a second question, which is the only thing this page is trying to help you do.

The lines the NHS draws

Two of them, and they are different lines for different situations. Quoted rather than summarised, because a vague version helps nobody decide.

Urgent. Ask for an urgent GP appointment or help from NHS 111 if the pain is severe or worse than usual and painkillers have not helped.

Not urgent, but book it. See a GP if your periods become more painful, heavier or irregular, or if the pain stops you doing your usual daily activities.

Two more things the NHS says belong here. An IUD can cause period pain, particularly in the first 3 to 6 months after it is put in — so a coil fitted this spring is a reasonable thing to raise rather than a coincidence to ignore. And pain that arrives with heavier bleeding is a pair of symptoms rather than one: the NHS's own list of what counts as heavy is a set of concrete tests, set out in what actually counts as a heavy period. If the change is in the timing rather than the pain, irregular periods is the page for that.

What a doctor is investigating

ACOG's name for the other kind is secondary dysmenorrhoea: pain caused by a disorder in the reproductive organs, which tends to get worse over time and often lasts longer than normal menstrual cramps. The NHS names four conditions that can cause painful periods — endometriosis, adenomyosis, fibroids and pelvic inflammatory disease.

Naming them is the honest thing to do and it is where this page stops. It cannot tell you which, if any, applies to you, and nor can any web page: that is what an examination and tests are for.

Endometriosis, named carefully

It gets its own heading because it is the one people arrive already worrying about, and because both of the publishers this page stands on are unusually frank about how hard it is to pin down.

ACOG says endometriosis occurs in about 1 in 10 women of reproductive age and is most often diagnosed in women in their 30s and 40s, that its most common symptom is chronic pelvic pain especially just before and during the period, that heavy menstrual bleeding is another, that many women with it have no symptoms at all — and that the only way to tell for sure is a surgical procedure called laparoscopy.

The NHS describes it as cells similar to those in the lining of the womb growing in other parts of the body, and lists among its symptoms severe period pain that stops you doing normal activities, heavy periods, pain in the lower tummy and back, pain when you poo or pee, pain during or after sex, and extreme tiredness. It says it can take a long time to diagnose and that several different tests may be needed, because the symptoms can be similar to other conditions, and that a laparoscopy can confirm it. It also says there is currently no treatment that cures it, though treatment can help manage symptoms such as pain. Its advice on when to go: see a GP if you think you might have it, or if your symptoms are affecting your everyday life, work and relationships.

What that adds up to is not a self-test. It is a word worth saying out loud at an appointment, and a reason to bring a written record rather than an impression, because "it can take a long time to diagnose" is the part of the NHS's description that a good record shortens.

What helps, in the publishers' own words

Two organisations publish a list, and this section is theirs rather than ours. Nothing here is a recommendation for you specifically, because nobody writing a web page knows what else you take or what else you have.

Heat. The NHS suggests a heat pad or a hot water bottle wrapped in a tea towel on your tummy. ACOG says a warm bath or a heating pad on the abdomen can be soothing. It is the least interesting item on the list and the one most people already know works.

Movement. The NHS names gentle exercise — yoga, swimming, walking, cycling. ACOG puts it more strongly: exercising most days of the week can make you feel better, and aerobic workouts help produce chemicals that block pain. This is the opposite of resting through it, and it is worth noticing that it comes from the same source as everything else on this page.

Painkillers, with a caveat that belongs next to them. The NHS lists painkillers. ACOG is specific about why one class works: nonsteroidal anti-inflammatory drugs reduce the prostaglandins the body makes and lessen their effects, they work best taken at the first sign of a period or of pain, and they are usually taken for only a day or two. ACOG also names who should not take them — women with bleeding disorders, asthma, aspirin allergy, liver damage, stomach disorders or ulcers. That last sentence is the reason a pharmacist is worth two minutes: free, no appointment, and they can check the list against you rather than against nobody.

Hormonal contraception. The NHS says contraception such as the pill, implant or injection thins the womb lining, which makes periods lighter and eases the pain. ACOG says birth control containing estrogen and progestin can be used to treat painful periods. That is a prescription conversation, not a purchase.

And two smaller ones. The NHS adds that cutting down on alcohol and not smoking may help.

What none of them offers is a supplement, a diet or a protocol, and this page does not either. The NHS's own note that treatment can help manage the pain of endometriosis even though nothing cures it is worth carrying into any appointment: "nothing to be done" is not what any of these publishers says.

Turning pain into something an appointment can use

An appointment is short and memory is unreliable, especially about pain, which is remembered as a general impression rather than as a series of days. A written record fixes that, and it is the single most useful thing you can bring.

Four columns are enough: the date, where the pain was, what it stopped you doing, and what you took and whether it helped. Two or three cycles of that turns "my periods are painful" into "it starts the day before, it is worst on day one, I missed work in two of the last three months, and the painkillers I took did not touch it" — which is a different conversation. The printable symptom tracker lays that out on one page you can hand across a desk. The printable period tracker carries the start dates alongside it, because pain that is drifting away from your period is itself worth knowing about.

If you would rather see where you are in the cycle before you write anything down, the cycle phase calculator estimates it from your own dates and is straight about how wide the uncertainty around a phase boundary really is. It runs in your browser and keeps nothing.

What to actually say in that appointment, and what a record has to contain before it is worth carrying in, is set out in talking to a doctor about your periods. And if the pain is landing on a school timetable rather than a work one, PE and periods covers that particular hour.