Alveolar development in the human fetus and infant

Early Hum Dev. 1986 Feb;13(1):1-11. doi: 10.1016/0378-3782(86)90092-7.


The lungs from 29 infants aged from 29 weeks of gestation to 18 weeks postnatal age were studied using morphometric analysis; total DNA was estimated in 12 of these. Alveoli could first be counted and measured at 29 weeks gestation; with increasing age they became more mature in appearance as the walls elongated and thinned, and they gradually increased in diameter. Lung volume increased 4-fold between 29 weeks and term, and further doubled in the 4 months after birth. Lung volume, alveolar surface area and DNA all increased linearly with age and weight. Alveolar number showed a curvilinear increase with age and DNA, but a linear relationship to body weight. At birth the lungs had an average of 150 million alveoli, half of the expected adult number. There was a wide normal range. The surface area was between 3 and 5 m2 at birth, one twentieth of the adult value.

MeSH terms

  • Body Weight
  • DNA / analysis
  • Female
  • Gestational Age
  • Humans
  • Infant
  • Infant, Newborn
  • Lung / analysis
  • Lung / embryology
  • Male
  • Pulmonary Alveoli / embryology*
  • Pulmonary Alveoli / growth & development


  • DNA