Period pain

What it is

Primary dysmenorrhoea is period pain with no underlying disease. Prostaglandins released as the uterine lining breaks down make the uterus contract strongly, and strong contractions temporarily reduce its own blood supply - which is what produces cramping pain, in the same way angina does in heart muscle.

On top of that sits a second layer that is much more amenable to physical treatment: the abdominal wall, pelvic floor, low back and hip muscles guard against the pain, which restricts blood flow further and refers pain into the back and inner thighs. That layer is where exercise, heat and massage make their difference.

What it feels like

• Cramping in the lower abdomen, often coming in waves
• A dragging ache in the lower back and the tops of the inner thighs
• Worst in the first day or two of bleeding
• Nausea, loose bowels, headache or fatigue alongside it
• Curling up and bracing, which helps for a moment and tightens everything

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Prostaglandin-driven uterine contraction

Prostaglandins released as the lining sheds cause the uterus to contract hard. Women with more severe pain generally have higher prostaglandin levels, and this is why anti-inflammatory painkillers work well when taken early.

Reduced blood flow during contraction

A strongly contracting uterus temporarily compresses its own blood supply. The pain is genuinely ischaemic, which is why it comes in waves matching the contractions.

Protective guarding of the abdominal wall and pelvic floor

The body braces around pain. Sustained tension in the abdominal and pelvic muscles restricts blood flow further and produces its own aching, adding a layer that is entirely muscular.

Referred pain into the back and thighs

The uterus shares nerve supply with the lower back and inner thighs, so the pain is genuinely felt there. Muscle guarding in those areas then adds a second, local source of pain.

Stiff hips and a stiff low back

Restricted hips and lumbar spine mean less movement and less circulation through the whole pelvis, and there is less capacity to move in ways that ease the guarding.

Inactivity

Regular exercise reduces period pain in trials, probably through improved pelvic blood flow, endorphin release and lower prostaglandin sensitivity. Being inactive removes that protection.

Stress and poor sleep

Both lower pain thresholds, and both are common in the premenstrual week. The same physical event hurts more in a hard month.

Secondary causes

Endometriosis, adenomyosis, fibroids and pelvic inflammatory disease all cause period pain and need different treatment. Pain that started later in life, is worsening, lasts beyond the period, or comes with pain during sex or bowel movements is a different conversation.

Who tends to get it

• Younger women, in whom primary dysmenorrhoea is most common and usually eases with age
• Anyone with heavy periods
• Smokers, in whom period pain is consistently more severe
• Women who are inactive, which removes one of the few protective factors
• Anyone under high stress or sleeping badly in the premenstrual week

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineMenopause & Cycle Support

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

New severe pain, heavy bleeding, or pain outside menstruation needs gynecological review (endometriosis)

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Regular exercise across the cycle reduces pain severity measurably within two to three cycles, which is worth knowing because the effect is not immediate and people abandon it after one month. Heat and gentle movement help during the period itself. Primary dysmenorrhoea often eases with age and after childbirth. Pain that is severe enough to stop you functioning, that began later in life, that is getting worse, or that comes with pain during sex, bowel movements or urination needs proper investigation rather than management.

Prevalence basis: WHO and gynecology society estimates; one of the highest-prevalence entries on this list

Others the same routine covers

These share the Menopause & Cycle Support routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.