Scientists used to think that babies’ airways and lungs were sterile at birth and colonized with microbes only after that.
Babies’ Airways Are Colonized Before Birth:
New research from the University of Alabama at Birmingham has found that even preterm infants are born with their airways already colonized. An imbalance in the respiratory microbiome may set very low birthweight babies up for a lung disease linked to prematurity, bronchopulmonary dysplasia. Infants who did not develop this condition, despite being born very small, had more Lactobacillus organisms living in their airways.
This is the first study of the respiratory microbiota at birth, and it was confirmed in a second study of extremely low birthweight babies at Drexel University College of Medicine in Philadelphia. Babies born vaginally and those delivered by Caesarean section had similar microbes already resident in their airways.
The authors suggest that prenatal colonization of babies’ airways might be linked to the microbiome now known to exist in the amniotic fluid and placenta. Presumably having an appropriate balance of bacteria can help prime the infant’s immune system to function properly. A skewed balance, with too few of the “right” bacteria and too many of the “wrong” kind, seems to set the baby up for breathing trouble.