What causes dizziness in a female patient on the second day of her menstrual period?

Dizziness on Day 2 of Menstrual Period

Dizziness on the second day of menstruation is most commonly caused by iron deficiency anemia from heavy menstrual bleeding, prostaglandin-mediated vasodilation, or menstrual migraine, and requires assessment of bleeding severity, orthostatic vital signs, and associated symptoms to guide management.

Primary Causes to Evaluate

Heavy Menstrual Bleeding with Anemia

• Severe menorrhagia can cause acute anemia leading to weakness, fatigue, dizziness, and headaches during the menstrual period 1
• Look specifically for: passage of large clots, bleeding lasting >7 days, soaking through pads/tampons hourly, and associated symptoms of weakness and fatigue 1
• Check orthostatic vital signs immediately—a drop in blood pressure upon standing indicates significant volume depletion or anemia 1
• Obtain complete blood count to assess for anemia; severe cases may show hemoglobin <7 g/dL with reactive thrombocytosis 1

Menstrual Migraine

• Approximately 60% of women with migraine report increased headache frequency during menses, and these headaches are characteristically more severe and longer-lasting than non-menstrual migraines 2
• Estrogen withdrawal just prior to menses triggers loss of serotonergic tone, precipitating migraine attacks 2, 3
• Menstrual migraines typically occur from 2 days before to 3 days after menstruation onset 4, 3
• Key distinguishing features: throbbing headache, photophobia, nausea, and functional disability; menstrual migraines often lack aura 4
• Have the patient maintain a 3-month headache diary to document the predictable pattern of headaches relative to menstruation 4

Prostaglandin-Mediated Effects

• Prostaglandins released during menstruation cause uterine cramping but also systemic vasodilation, which can contribute to lightheadedness 5, 6
• This mechanism explains why NSAIDs (which inhibit prostaglandin synthesis) can relieve both cramping and associated dizziness 5

Immediate Management Algorithm

Step 1: Assess Severity and Rule Out Dangerous Causes

• Obtain orthostatic vital signs to evaluate for significant blood loss or volume depletion 1
• Ask about neurologic symptoms (dysphonia, dysphagia, visual changes, focal weakness) that would suggest stroke—though stroke typically causes permanent deficits, not cyclical symptoms 7
• Verify this is true "dizziness" (lightheadedness/presyncope) rather than vertigo (spinning sensation), as vertigo suggests vestibular pathology unrelated to menstruation 7

Step 2: Quantify Menstrual Blood Loss

• Document number of pads/tampons used per day, presence of clots, duration of bleeding 1
• If heavy bleeding is present, order CBC, ferritin, and consider coagulation studies if family history of bleeding disorders 1

Step 3: Treat Based on Primary Cause

For Heavy Bleeding with Anemia:

• Start naproxen sodium 440-550 mg every 12 hours to reduce menstrual blood flow and provide symptomatic relief 5
• Initiate iron supplementation for documented iron deficiency 1
• If NSAIDs fail or bleeding is severe, refer for hormonal contraceptive options or gynecologic evaluation 5

For Menstrual Migraine:

• Acute treatment: NSAIDs (naproxen) at onset of headache 8, 4
• Perimenstrual prophylaxis: Start naproxen sodium 2 days before expected menstruation and continue for 5 days 5, 8, 4
• Alternative prophylaxis: Long-acting triptans (frovatriptan, naratriptan) used perimenstrually for 5 days 8, 3
• For frequent migraines requiring long-term prevention: beta-blockers (propranolol 80-160 mg daily or metoprolol 50-100 mg twice daily) 8

For Prostaglandin-Mediated Symptoms:

• Naproxen sodium 440-550 mg every 12 hours starting with menstruation 5
• Add heat therapy (heating pad to abdomen) for additional relief 5

Important Caveats

Contraindications to NSAIDs

• Do not prescribe NSAIDs if patient has active peptic ulcer disease, cardiovascular disease, renal insufficiency, or history of GI bleeding 5
• Use lowest effective dose for shortest duration, especially in patients at risk for bleeding or renal impairment 5
• Never prescribe opioids for menstrual-related symptoms—they are not more effective than NSAIDs and carry significant risks 5

When to Refer

• Dizziness with loss of consciousness (true syncope) requires cardiac and neurologic evaluation 7
• Persistent symptoms despite NSAID therapy warrant gynecologic referral for consideration of hormonal contraceptives or evaluation for secondary dysmenorrhea 5
• Severe anemia (hemoglobin <7 g/dL) or suspected bleeding disorder requires hematology consultation 1

Hormonal Considerations

• If patient has migraine with aura, combined hormonal contraceptives are absolutely contraindicated due to stroke risk; use progestin-only options instead 8
• Reproductive endocrine disorders (PCOS, hypothalamic amenorrhea, hyperprolactinemia) can cause menstrual irregularity and should be evaluated if cycles are consistently abnormal 7