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Pediatrics

Neonatal chest radiograph - imaging hints of preterm versus term birth

Knowing gestational age at birth is essential to interpretation of neonatal chest radiography. The best way to be sure is to check the EMR. For speed, you can also use humeral head ossification as a clue, but you'll need to know how to use this clue properly.

Humeral head ossification in a term newborn at day 0. On the left is the original radiograph. On the right is the same radiograph with ossified humeral heads outlined. Notice how far these ossification centers are from the rest of the humerus. This patient was born with meconium-stained amniotic fluid and respiratory distress.

Basic Definitions

  • Term birth is >=37 weeks
  • Preterm birth is <37 weeks

Humeral Head Ossification

  • If you see the humeral heads ossified, you can be sure your patient was born at term.
  • If the humeral heads are not ossified, the patient could be either preterm or term birth.
Two different term newborns with (left) and without (right) humeral head ossification at day 0. Presence of humeral head ossification is a strong sign of term birth, but absence of humeral head ossification does not necessarily mean preterm birth. Both patients were born with meconium-stained amniotic fluid and respiratory distress.