At what age does the foramen ovale (FO) typically close in babies?

Foramen Ovale Closure Timing in Infants

The foramen ovale typically closes functionally within 24-48 hours after birth in most infants, but anatomical closure occurs gradually over the first year of life, with approximately 75% closed by age one. 1

Normal Closure Process

The closure of the foramen ovale follows a predictable pattern:

• Functional closure: Occurs within 24-48 hours after birth

  • Triggered by increased left atrial pressure following the establishment of pulmonary circulation
  • Results in the septum primum pressing against the septum secundum, creating a functional seal

• Anatomical closure: Progressive process over months

  • Complete fusion of the septum primum and secundum
  • By age one year: approximately 75% of infants have complete anatomical closure
  • By adulthood: 25-27% of people have persistent patent foramen ovale (PFO) 1, 2

Factors Affecting Closure

Several factors can influence the timing and likelihood of foramen ovale closure:

• Gestational age: Premature infants may experience delayed closure
• Congenital heart defects: Can prevent normal closure
• Pulmonary hypertension: May delay or prevent closure due to altered pressure gradients

Clinical Significance of Persistent PFO

When the foramen ovale fails to close, it results in a patent foramen ovale (PFO):

• Prevalence: Present in approximately 25-27% of adults 1, 2
• Age-related decline: The prevalence of PFO appears to decline with age 1
• Clinical implications:
  • Most PFOs are asymptomatic and clinically insignificant
  • Associated with cryptogenic stroke, particularly in younger adults (<55 years) 1
  • May serve as a pathway for paradoxical embolism 2
  • Linked to decompression illness in divers and migraine with aura 3, 4

Diagnostic Considerations

If PFO is suspected beyond the expected closure period:

• Gold standard: Contrast-enhanced transesophageal echocardiography 3
• Alternative methods:
  • Transthoracic echocardiography with contrast
  • Transcranial Doppler sonography
  • Cardiac MRI or CT with contrast

Management of PFO

For patients with persistent PFO:

• Observation: Appropriate for asymptomatic individuals
• Medical therapy: Antiplatelet or anticoagulation therapy for those with cryptogenic stroke 1
• PFO closure: Consider for selected patients with cryptogenic stroke under age 60 1, 5, 2

Important Caveats

• Normal variant: PFO is a normal anatomical variant in 25% of adults
• Incidental finding: Most PFOs are discovered incidentally and require no intervention
• Age consideration: The association between PFO and stroke is stronger in younger patients (<55 years) 1
• Risk stratification: Tools like the RoPE score and PASCAL classification help determine the likelihood that a PFO is pathogenic in stroke patients 5, 2

Common Pitfalls

• Overdiagnosis: Not all PFOs require treatment or intervention
• Inappropriate closure: PFO closure should be reserved for carefully selected patients
• Incomplete evaluation: When evaluating stroke patients with PFO, comprehensive workup for other stroke etiologies is essential 5
• Post-closure monitoring: Patients who undergo PFO closure require follow-up for potential complications including atrial fibrillation 5, 6