Newborn with inspiratory stridor that worsens when supine is most consistent with which condition?

• A. Vocal cord paralysis
• B. Laryngomalacia
• C. Tracheomalacia
• D. Croup

Answer: (B)

Worsening inspiratory stridor when a newborn is supine is classic for laryngomalacia. In this condition the structures above the glottis are unusually floppy and tend to collapse inward during inspiration, creating a high-pitched, musical sound. When the baby lies on the back, gravity and reduced airway support make this collapse more likely, so the stridor becomes more noticeable. Laryngomalacia typically presents in the first weeks of life with inspiratory stridor that can be aggravated by feeding, agitation, and lying supine, and it often improves when the baby is placed prone and gradually resolves over the first year or two.

Other causes have different patterns: vocal cord paralysis can cause inspiratory or biphasic noise but doesn’t have the classic positional worsening; tracheomalacia tends to produce expiratory or biphasic sounds and may worsen with crying; croup is associated with a barky cough and typically follows a viral illness rather than being tied to body position.