Overview
Premenstrual syndrome (PMS) refers to a collection of physical and emotional symptoms that occur in the luteal phase of the menstrual cycle (typically 1 to 2 weeks before the period) and resolve within a few days of menstruation starting. Premenstrual dysphoric disorder (PMDD) is a severe form with prominent mood symptoms that significantly impair daily functioning.
How common is it?
Premenstrual symptoms are common and vary between people and between cycles. A smaller number have severe symptoms called PMDD that substantially affect everyday life.
Causes and risk factors
The cause is not fully understood. PMS and PMDD may involve increased sensitivity to normal changes in reproductive hormones, with effects on mood and physical symptoms.
Common risk factors
- Abnormal sensitivity to progesterone metabolites (allopregnanolone) in genetically susceptible women
- Serotonin system dysregulation in the luteal phase
- Inherited differences may contribute to susceptibility, particularly in PMDD.
- Stress amplifies severity
- Evidence for magnesium or vitamin B6 supplements is limited; symptoms do not establish a deficiency.
- Calcium deficiency is not established by PMS symptoms; discuss dietary concerns before taking supplements.
- Psychological vulnerability (history of depression, anxiety, or trauma increases PMDD risk)
Symptoms
- Mood changes: irritability, mood swings, anxiety, low mood, tearfulness
- Physical: breast tenderness and swelling, bloating, headache, fatigue, acne
- Behavioural: food cravings, poor concentration, social withdrawal
- PMDD: severe depression, hopelessness, marked anger, suicidal thoughts in the luteal phase
- Symptom diary over 2 months is needed to confirm the cyclical pattern
When to see a doctor
See a GP if premenstrual symptoms affect work, relationships or daily life. Severe depression or suicidal thoughts need urgent assessment. If you cannot keep yourself safe, seek emergency care now; do not wait for your period or a symptom diary.
Diagnosis
Prospective daily symptom diary over 2 complete menstrual cycles is essential to establish cyclical timing and severity. Blood tests rule out thyroid disorder, anaemia, and endocrine conditions. PMDD is diagnosed against DSM-5 criteria.
Treatments
SSRIs (first-line for PMDD)
SSRIs (fluoxetine, sertraline, escitalopram) are the most effective treatment for PMDD. Can be used continuously or only in the luteal phase (from ovulation to menstruation). Effect is rapid, often within the first treated cycle.
Combined oral contraceptive (DRSP-containing)
A combined contraceptive pill, sometimes one containing drospirenone, may help PMS symptoms. It is not suitable for everyone; a clinician should assess clot risk, migraine history, blood pressure and diabetes complications before prescribing.
GnRH agonists (second-line)
Suppress ovarian function and cyclical hormonal changes. Highly effective but cause menopausal symptoms and bone loss with long-term use. Add-back HRT is given alongside them.
Lifestyle and supplements
Regular exercise may help symptoms. Evidence for magnesium, calcium and vitamin B6 supplements is limited. Ask a pharmacist or GP before using them; excessive vitamin B6 can cause nerve damage.
Self-care and lifestyle
- Aerobic exercise 3 to 4 times per week throughout the cycle
- Reduce caffeine and alcohol, especially in the luteal phase
- Eat regular balanced meals (blood sugar swings worsen mood symptoms)
- Sleep consistently 7 to 9 hours per night
Prevention
PMS and PMDD cannot be prevented but can be effectively managed. Identifying the cyclical pattern through diary keeping is the first step toward effective treatment.
Sources for targeted updates
Updated: 24 October 2026. Targeted corrections to treatment, causes, key facts, urgent-care guidance, frequency, risk factors. This update covers the named sections; a full review of the remaining guide is pending.