Premenstrual syndrome explained

Defining PMS

PMS is more than the casual use of the term suggests. Knowing the clinical features helps you make sense of your own experience.

The core definition

Premenstrual syndrome describes a pattern of physical and emotional symptoms occurring in the luteal phase of the menstrual cycle, typically in the week or two before periods, with significant improvement once periods start. The pattern repeats across cycles. PMS can affect women throughout reproductive life, though severity often varies with age and life circumstances.

How common it is

Up to 80 percent of women experience some premenstrual symptoms. Around 20 percent have symptoms significant enough to affect daily life. A smaller proportion, around 3 to 8 percent, has severe symptoms meeting criteria for PMDD. The wide spectrum is part of why PMS gets dismissed as common, even though for some women it is genuinely disabling.

The symptom range

Physical symptoms include breast tenderness, bloating, headaches, fatigue, joint or muscle pain, food cravings and sleep disruption. Emotional symptoms include irritability, mood swings, anxiety, low mood and emotional sensitivity. Many women experience some combination of both. The specific symptoms and severity vary between women and across the lifespan.

When it is more than PMS

PMS that significantly disrupts life, particularly with severe mood symptoms, may be PMDD. PMS that gets dramatically worse during perimenopause may reflect changing hormonal patterns. PMS that does not improve with period onset may indicate something else. Severe or unusual patterns warrant medical assessment. Speak to your GP.

Why PMS happens

PMS is biologically real. The mechanisms are not fully understood but several factors contribute.

The hormonal pattern

The dropping levels of oestrogen and progesterone in the late luteal phase appear to be involved. The brain is sensitive to the rate of hormonal change rather than absolute levels. Women with PMS appear to be more sensitive to normal hormonal fluctuations than those without, rather than having abnormal hormone levels.

The serotonin connection

Hormonal changes affect serotonin, the brain chemical involved in mood. Low serotonin contributes to mood and emotional symptoms of PMS. This is why SSRI antidepressants, which raise serotonin activity, help PMS. The serotonin model explains why mood symptoms are such a prominent feature of PMS for many women.

Other contributors

Inflammation in the body may worsen PMS symptoms. Genetic factors play a role, with PMS often running in families. Stress amplifies PMS symptoms. Lifestyle factors including sleep, exercise and diet influence severity. The full picture involves multiple interacting factors rather than one single cause.

What it is not

PMS is not a character weakness, lack of self control or attention seeking. The dismissal of PMS as women being dramatic or hysterical reflects centuries of women's symptoms being trivialised. PMS is a recognised clinical condition with biological basis. The symptoms are real. Treatment helps.

Treatment options

PMS responds to several different approaches. Most women benefit from a combination rather than relying on one intervention.

Lifestyle approaches

Regular exercise, particularly aerobic activity, helps PMS for many women. Adequate sleep matters. Reducing alcohol, caffeine and refined carbohydrates may help. Stress management techniques including mindfulness can reduce severity. These changes alone may not control severe PMS but support other treatments and have wider health benefits.

Supplements with evidence

Calcium supplementation has reasonable evidence for reducing PMS symptoms. Vitamin B6 may help mood symptoms for some women. Magnesium may help. Evening primrose oil has weak evidence. The supplement market makes many claims with little support. Stick to the supplements with reasonable evidence and speak to your GP before starting them, particularly if you take other medication.

Medical treatment

The combined contraceptive pill helps many women with PMS by stabilising hormones across the cycle. SSRIs help significantly with mood symptoms of PMS. They can be taken continuously or just in the luteal phase. Tranexamic acid helps with heavy bleeding if that is a feature. For severe PMS, more aggressive treatments may be appropriate.

Cognitive behavioural therapy

CBT adapted for PMS has good evidence for improving symptoms and reducing impact on daily life. The therapy helps with coping strategies and managing the impact on relationships and work. NHS access varies but is improving. Self help CBT resources for PMS exist. Speak to your GP about referral options.

Practical considerations

Beyond treatment, practical strategies help manage the day to day impact of PMS. The combination of treatment and management produces the best outcomes.

Tracking your pattern

Cycle tracking helps you identify when symptoms typically appear and which symptoms are most prominent for you. Patterns become clearer across several cycles. Apps designed for cycle tracking simplify the process. Knowing your pattern helps you plan around the difficult days and gives your GP useful information.

Planning around it

Once you know your pattern, you can plan demanding work, social commitments or important decisions around it where possible. This is not always practical but where it is, it helps. Lighter exercise, better sleep priority and easier eating in the difficult days support your function rather than fighting against it.

Communicating about it

Partners, family and trusted colleagues benefit from understanding your pattern. PMS affects relationships and work performance. Open communication helps. You do not need to apologise for having PMS but explaining the pattern lets people support you appropriately. The cultural conversation about cyclical health is improving, slowly.

When to seek help

If PMS is significantly affecting your life, see your GP. If you suspect PMDD (severe mood symptoms meeting specific criteria), track symptoms across two cycles and bring the record to your appointment. If treatment is not working, request a referral to a specialist menopause or gynaecology service. The condition has effective treatments. Persistence often pays off.

More on female health

For the severe form, our PMDD: The Severe Form of Premenstrual Mood Disorder covers the clinically diagnosed condition. The Menstrual Cycle: A Complete Guide covers the cycle pattern PMS sits in. And The Four Hormonal Phases of the Menstrual Cycle covers the phases in detail.