Effects of delivery by caesarean section on lung function in healthy newborn infants.

With the aim of extending previous studies showing differences in lung function after birth between infants delivered vaginally (VD) and by Caesarean section (CS) we investigated lung volumes, ventilation, efficiency of ventilation, and lung mechanics in 24 healthy, full term infants with no clinical signs of respiratory disease, 12 after VD and 12 after CS. Measurements were made on two occasions: 2 and 26 hours after birth. At 2 hours no differences in any measured quantity were found between the groups. The only difference found 24 hours later was that the average thoracic gas volume (TGV), was lower in infants after CS than after VD. The difference in functional residual capacity was, however, not significant. This means that the difference in TGV, previously also found by other workers, did not affect the ventilated air space. Our results do not support the theory of general inferiority in lung performance after birth in healthy, full term infants without respiratory disease delivered by CS.