A 38-year-old woman with a new occipital headache that started two days ago at the onset of her menstrual period, who is normotensive and has no red‑flag symptoms, what is the most likely diagnosis and first‑line treatment?

Menstrual-Related Migraine Without Aura

This is a menstrual-related migraine without aura, and first-line treatment is NSAIDs (naproxen 500-825 mg or ibuprofen 400-800 mg) taken at headache onset, with the option to add a triptan if NSAIDs alone provide inadequate relief. 1

Diagnosis

The temporal relationship between headache onset and menstruation onset (both starting two days ago) strongly suggests menstrual-related migraine. 2, 3 Key diagnostic features include:

• Occipital location is consistent with migraine presentation 1
• Normal blood pressure (114/80) rules out hypertensive emergency or preeclampsia-related headache 4
• Timing with menses indicates estrogen withdrawal as the trigger mechanism 2, 5
• No aura reported classifies this as migraine without aura 2

Menstrual-related migraine affects 20-25% of female migraineurs and is defined as migraine occurring on day 1 ± 2 of menstruation (but may also occur at other times in the cycle, unlike pure menstrual migraine which occurs exclusively perimenstrually). 3

First-Line Acute Treatment

Start with NSAIDs immediately:

• Naproxen sodium 500-825 mg at headache onset, can repeat every 2-6 hours as needed (maximum 1.5 g/day) 1
• Ibuprofen 400-800 mg is an alternative first-line option 6, 1
• NSAIDs work best when taken early while pain is still mild 1

Add antiemetic if nausea is present:

• Metoclopramide 10 mg provides synergistic analgesia beyond just treating nausea 1
• Give 20-30 minutes before the NSAID to enhance absorption 1

Escalation if NSAIDs Fail

If NSAIDs provide inadequate relief after 2-3 episodes, add a triptan:

• Sumatriptan 50-100 mg PLUS naproxen 500 mg is superior to either agent alone, with 130 more patients per 1000 achieving sustained pain relief at 48 hours 1
• Alternative oral triptans include rizatriptan 10 mg (fastest oral triptan), eletriptan 40 mg, or zolmitriptan 2.5-5 mg 1
• Subcutaneous sumatriptan 6 mg provides highest efficacy (59% complete pain relief at 2 hours) if rapid onset is needed 1

Critical Frequency Limitation

Restrict all acute medications to no more than 2 days per week to prevent medication-overuse headache, which paradoxically increases headache frequency and can lead to daily headaches. 6, 1 This non-negotiable limit applies to NSAIDs, triptans, and all acute agents. 1

When to Initiate Preventive Therapy

Consider preventive treatment if:

• Headaches adversely affect quality of life on ≥2 days per month despite optimized acute therapy 6
• Acute medications are needed more than twice weekly 6, 1
• Menstrual attacks are predictably severe and disabling 6, 7

Short-term perimenstrual prophylaxis options (started 2 days before expected menses, continued through day 3 of menstruation):

• Naproxen 500 mg twice daily during the 5-day perimenstrual window 8, 7
• Frovatriptan 2.5 mg twice daily or other triptan during the perimenstrual window 7
• This approach takes advantage of the predictable timing of menstrual migraine 7

Long-term preventive options if attacks occur frequently throughout the cycle:

• Beta-blockers (propranolol 80-240 mg/day, metoprolol, or atenolol) are first-line 6
• Topiramate 50-100 mg/day is first-line with strong evidence 6
• Candesartan 16-32 mg/day is first-line 6

Pathophysiology Relevant to Treatment

Estrogen withdrawal immediately before menstruation triggers loss of serotonergic tone, precipitating migraine attacks. 5 This explains why:

• Menstrual migraines are typically more severe, longer duration, and more treatment-resistant than non-menstrual attacks 5, 3
• Triptans (serotonin receptor agonists) are particularly effective for menstrual migraine 5
• Maintaining stable estrogen levels (via transdermal estrogen patches during perimenstrual window) can prevent attacks, though this is a specialized approach 8

Critical Pitfalls to Avoid

• Do not prescribe opioids or butalbital-containing compounds—these have questionable efficacy, cause dependency, trigger rebound headaches, and lose efficacy over time 6, 1
• Do not allow frequent acute medication use in response to recurring attacks—this creates medication-overuse headache; instead transition to preventive therapy 6, 1
• Do not dismiss the menstrual relationship—menstrual migraines are a distinct disorder requiring recognition of their predictable pattern and potentially different treatment approach 3