Assessment and Plan for Irregular Menstruation and Headaches
Begin by determining if headaches are temporally related to menstruation (occurring between 2 days before through day 3 of menses), as this fundamentally changes both the diagnostic approach and treatment strategy.
Initial Assessment Algorithm
Step 1: Characterize the Menstrual Pattern
- Document cycle length, duration, and regularity over at least 3 months using a prospective diary 1
- Identify if oligomenorrhea (cycles >35 days), amenorrhea (absent menses >3 months), or regular cycles with breakthrough bleeding
- Note age at menarche and any history of previously regular cycles
Step 2: Characterize the Headache Pattern
Critical screening questions 2:
- "Do headaches occur between 2 days before through day 3 of your period most months?"
- "When headaches are related to your period, do they become severe?"
- "When headaches are related to your period, does light bother you more than usual?"
If question 1 is positive plus ≥1 other question positive: sensitivity 94%, specificity 74% for menstrual migraine 2
Document specific features:
- Unilateral vs bilateral location
- Duration (minutes vs hours vs days)
- Associated symptoms: nausea, photophobia, phonophobia, aura, autonomic features (lacrimation, rhinorrhea, conjunctival injection)
- Severity and disability level
- Response to prior treatments
Step 3: Mandatory Laboratory Exclusions
- TSH (exclude thyroid dysfunction)
- Prolactin (morning, resting, NOT postictal; exclude hyperprolactinemia if >20 μg/L) 1
- 17-hydroxyprogesterone (day 3-6 of cycle; exclude non-classic congenital adrenal hyperplasia if elevated) 3, 4
- Pregnancy test if any missed menses, irregular bleeding, pelvic pain, or before starting new medications 5
Step 4: Hyperandrogenism Evaluation (if irregular menses present)
Obtain on days 3-6 of cycle 1:
- LH/FSH ratio (>2 suggests PCOS)
- Total testosterone (>2.5 nmol/L abnormal)
- Mid-luteal progesterone (<6 nmol/L indicates anovulation) 1
Additional testing if indicated:
- Androstenedione (>10.0 nmol/L: rule out adrenal/ovarian tumor) 1
- Fasting glucose/insulin ratio (>4 suggests insulin resistance) 1
- Pelvic ultrasound (≥10 peripheral cysts 2-8mm diameter suggests polycystic ovaries) 1
Step 5: Red Flags Requiring Urgent Evaluation
- Rapid onset virilization (clitoral hypertrophy, voice deepening, male-pattern baldness, severe hirsutism): suspect androgen-secreting tumor 3
- Very high androgen levels: neoplasm workup 3
- New severe unilateral headache with autonomic features lasting 5-20 minutes, 5-8 times daily: consider paroxysmal hemicrania (requires indomethacin trial) 6
- Headache with papilledema: exclude idiopathic intracranial hypertension 7
Management Algorithm
For Menstrual-Related Headaches (Menstrual Migraine)
If headaches occur exclusively days -2 to +3 of menses (pure menstrual migraine) OR at these times plus other cycle times (menstrually-related migraine):
First-line acute treatment 8, 9:
- Standard migraine abortive therapy (triptans, NSAIDs) at headache onset
- Treat aggressively as menstrual migraines are typically more severe and longer-lasting than non-menstrual attacks 10, 11
Short-term prophylaxis (for predictable cycles) 9, 12:
- Frovatriptan 2.5mg twice daily OR Naratriptan 1mg twice daily OR Zolmitriptan 2.5mg 2-3 times daily
- Start 2 days before expected menses, continue through day 3 of bleeding (total 5-7 days)
- This approach has strongest evidence among preventive strategies 9
Hormonal management (if contraception also desired) 12:
- Continuous combined hormonal contraceptives (CHCs) with NO placebo interval OR maximum 2 placebo days to prevent estrogen withdrawal trigger 12
- CONTRAINDICATION: Do NOT use CHCs if migraine with aura present (unacceptable health risk, especially with additional risk factors like smoking) 12
For Irregular Menses WITHOUT Menstrual Relationship to Headaches
If PCOS diagnosed (requires 2 of 3: hyperandrogenism, chronic anovulation, polycystic ovaries) 4:
Treatment priorities 3:
- Metabolic screening: 40-45% have impaired glucose tolerance or type 2 diabetes at presentation 3
- Weight management: Critical for insulin resistance and long-term cardiovascular risk 3
- Insulin-sensitizing agents: Consider metformin, especially if insulin resistance, obesity, acanthosis nigricans present 3
- Combined oral contraceptive + antiandrogen: Effective for hyperandrogenemia but may not address metabolic abnormalities 3
Critical counseling point: Discontinuation of therapy leads to recurrence; this requires long-term endocrinology follow-up for metabolic surveillance (diabetes, hypertension, dyslipidemia, atherosclerosis) 3
For Epilepsy Patients with Irregular Menses
PCOS prevalence is 10-25% in temporal lobe epilepsy patients, even without antiepileptic drugs 1. Valproate specifically increases risk. Follow same PCOS evaluation and management as above.
Common Pitfalls to Avoid
Do NOT prescribe oral contraceptives for "irregular cycles" without proper diagnostic workup 3. This delays diagnosis of hyperandrogenic disorders and misses opportunity for early metabolic intervention.
Do NOT assume all menstruation-associated headaches are migraine 6. Short-lasting unilateral attacks with autonomic features may be paroxysmal hemicrania requiring indomethacin.
Do NOT use estrogen-containing contraceptives in migraine with aura 12. This carries unacceptable thrombotic risk.
Do NOT overlook metabolic screening in PCOS 3. These patients require lifelong surveillance for diabetes and cardiovascular disease regardless of symptom control.
Do NOT rely on patient recall for menstrual-headache relationship 1, 2. Require prospective 3-month diary for accurate diagnosis.