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?
Up to 80% of women experience some premenstrual symptoms. About 20 to 30% have moderate PMS affecting daily life. PMDD affects 3 to 8% of women of reproductive age and is classed as a mental health condition in DSM-5.
Causes and risk factors
PMS and PMDD result from abnormal neurobiological response to normal cyclical fluctuations in oestrogen and progesterone, particularly affecting serotonin signalling in the brain.
Common risk factors
- Abnormal sensitivity to progesterone metabolites (allopregnanolone) in genetically susceptible women
- Serotonin system dysregulation in the luteal phase
- Genetic predisposition (heritability estimated at 50%)
- Stress amplifies severity
- Low magnesium and vitamin B6 levels associated
- Calcium deficiency
- 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 for PMS that significantly affects work, relationships, or daily function. Seek urgent help for suicidal thoughts or severe self-harm risk in PMDD — these warrant immediate specialist psychiatric assessment.
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)
Drospirenone-containing OCP (Yasmin, Eloine) or continuous COC use suppresses ovulation and eliminates cyclical hormonal fluctuation. Effective for both physical and mood PMS symptoms.
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
Magnesium 200 to 400mg daily reduces fluid retention and mood symptoms. Calcium 1,000mg daily reduces overall PMS severity. Vitamin B6 50mg has modest evidence. Aerobic exercise reduces symptom severity.
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.