What is physiological pregnancy pulsatile tinnitus?

Physiological Pregnancy Pulsatile Tinnitus

Physiological pregnancy pulsatile tinnitus is a normal finding during pregnancy characterized by the perception of a rhythmic sound synchronized with the heartbeat, resulting from pregnancy-related cardiovascular changes including increased cardiac output, peripheral vasodilation, and venous congestion. This condition is considered benign and typically resolves after delivery.

Pathophysiology

The development of pulsatile tinnitus during pregnancy stems from several normal physiological adaptations:

• Increased cardiac output: During pregnancy, cardiac output increases by 30-50% due to:

  • Increased stroke volume
  • Elevated heart rate (10-20 bpm above baseline) 1
  • Peak increase occurring by 32 weeks gestation

• Vascular changes:

  • Peripheral vasodilation leading to decreased systemic vascular resistance 1
  • Widened pulse pressure with bounding pulses 1
  • Expanded intravascular volume (50% increase) 1

• Venous adaptations:

  • Increased venous pressure (at or near upper limits of normal) 1
  • Venous congestion, particularly in head and neck regions

Clinical Presentation

Physiological pregnancy pulsatile tinnitus typically presents as:

• A rhythmic sound synchronized with the maternal pulse
• Often described as a "whooshing" or "rushing" sound
• May be more noticeable in quiet environments or when lying down
• Usually bilateral, though can be perceived more strongly on one side
• Often associated with a cervical venous hum, which can be appreciated in the right supraclavicular fossa 1

Distinguishing Features

Key characteristics that help identify physiological pregnancy pulsatile tinnitus:

• Cervical venous hum: Can be obliterated by movement of the chin toward the stethoscope or digital pressure over the ipsilateral jugular vein 1
• Timing: Typically develops in the second or third trimester as cardiac output reaches its peak
• Resolution: Spontaneously resolves after delivery when cardiovascular parameters return to pre-pregnancy state

Differential Diagnosis

While physiological pulsatile tinnitus in pregnancy is benign, it's important to rule out pathological causes:

• Arterial causes: Arteriosclerosis, dissection, fibromuscular dysplasia 2
• Arteriovenous causes: Arteriovenous fistulae, vascular tumors 2
• Venous causes: Intracranial hypertension, venous anomalies 2, 3
• Other: Jugular bulb abnormalities 4

Evaluation

For suspected physiological pregnancy pulsatile tinnitus:

1. History and physical examination:

   • Confirm timing with pulse
   • Check for associated symptoms (headache, visual changes, focal neurological symptoms)
   • Perform otoscopic examination to rule out visible retrotympanic mass

2. Auscultation:

   • Listen for cervical venous hum in the supraclavicular fossa
   • Attempt to abolish the sound with gentle jugular compression or head turning

3. Imaging:

   • Generally not required for typical physiological cases
   • Consider if symptoms are severe, unilateral, or associated with concerning features
   • MRI/MRA is preferred during pregnancy when imaging is necessary 5

Management

For physiological pregnancy pulsatile tinnitus:

• Reassurance: Explain the benign nature and expected resolution after delivery
• Positioning: Suggest left lateral positioning to reduce venous congestion 1
• Sound therapy: White noise or soft music may help mask the sound when bothersome
• Follow-up: Ensure symptoms resolve postpartum

Red Flags Requiring Further Investigation

Refer for further evaluation if:

• Unilateral tinnitus
• Associated hearing loss
• Neurological symptoms
• Visible abnormality on otoscopic examination
• Persistence beyond the postpartum period 5

Common Pitfalls

• Unnecessary imaging: Avoid extensive imaging for typical physiological cases
• Misdiagnosis: Don't confuse with pathological causes requiring intervention
• Overlooking associated symptoms: Always assess for signs of increased intracranial pressure or vascular abnormalities
• Failure to reassure: Inadequate explanation can lead to unnecessary anxiety

Physiological pregnancy pulsatile tinnitus is a benign condition that reflects normal cardiovascular adaptations during pregnancy and should resolve spontaneously after delivery.