Why Women Experience Premenstrual Headaches
Women develop headaches before their period primarily due to the rapid drop in estrogen levels that occurs 2-3 days before menstruation begins, triggering migraine attacks in hormonally susceptible individuals. 1
Hormonal Mechanism
The key trigger is estrogen withdrawal, not the absolute hormone level itself 2. This explains why:
- Approximately 50% of women with migraine experience increased attacks during menstruation, though only about 8% have attacks exclusively related to their period 3
- The headaches typically occur during the 2 days before and 3 days after menses onset, coinciding with the steepest decline in circulating estrogen 1, 4
- These menstrual migraines are usually without aura and tend to be more severe, longer-lasting, and more treatment-resistant than non-menstrual migraines 2, 4
Clinical Patterns
Any woman of reproductive age presenting with migraine should be asked about the relationship between attacks and menstruation 3. The pattern matters for classification:
- Pure menstrual migraine (1% prevalence): attacks occur only with menstruation 4
- Menstrually-related migraine (6-7% prevalence): attacks occur both during menstruation and at other times 3, 4
Treatment Approach
Acute Treatment
NSAIDs should be the initial choice, with strongest evidence for aspirin, ibuprofen, and diclofenac 3. The medication must be taken early when headache is still mild 3.
Triptans should be offered when NSAIDs provide inadequate relief 3. Among triptans, rizatriptan has the best overall evidence for acute treatment, with pain-free responses of 33-73% at 2 hours 4.
Short-Term Perimenstrual Prevention
If optimized acute therapy fails, initiate perimenstrual preventive treatment with a long-acting NSAID or triptan for 5 days, beginning 2 days before expected menstruation 3. Evidence supports:
- Frovatriptan twice daily (four randomized controlled trials) 4
- Naratriptan twice daily (two studies) 4
- Naproxen sodium 4
Long-Term Daily Prevention
For women requiring continuous prophylaxis, start with first-line agents: β-blockers (metoprolol or propranolol), valproate, venlafaxine, or amitriptyline 3. If ineffective, progress to CGRP-targeted therapies (oral gepants or monoclonal antibodies) 3. Topiramate is reserved as third-line only after adequate trials of both first-line and CGRP therapies have failed 3.
Important Caveats
Patient diaries tracking headache onset and menstrual timing through three complete cycles are essential for accurate diagnosis and treatment planning 5. This allows prediction of attack timing for perimenstrual prophylaxis.
Many antiepileptic preventive medications can reduce oral contraceptive efficacy, so caution is needed when combining these treatments 4. Topiramate has the least effect on oral contraceptives at doses below 200 mg/day 4.
During pregnancy, paracetamol is first-line despite poor efficacy, with NSAIDs only permitted in the second trimester 3. For breastfeeding women, paracetamol is preferred, though ibuprofen and sumatriptan are considered safe 3.