Mode of delivery and the lecithin/sphingomyelin ratio.
Babies born by elective Caesarean section are more likely to develop the respiratory distress syndrome that babies born vaginally. We studied the amniotic fluid and pharyngeal lecithin/sphingomyelin (L/S) ratios in three groups of babies born at term: 20 were delivered vaginally after elective induction of labour; 20 were delivered by elective Caesarean section; and 14 by Caesarean section after spontaneous onset of labour. Babies born after induction of labour had higher pharyngeal L/S ratios than babies born by elective Caesarean section. Those born by Caesarean section after spontaneous onset of labour had significantly higher pharyngeal L/S ratios than those in both of the elective delivery groups. There were no significant differences in the amniotic fluid L/S ratios of the two groups who underwent elective delivery. Regression analysis showed a significant relationship between length of labour and increase in the L/S ratio. These results indicate that, during labour, there is a release of fetal lung surfactant into the airways.
D000653:Amniotic Fluid / Q000032:analysis*; D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced; D010614:Pharynx / Q000032:analysis*; D010713:Phosphatidylcholines / Q000032:analysis*; D011247:Pregnancy; D012127:Respiratory Distress Syndrome, Newborn / Q000378:metabolism; D013109:Sphingomyelins / Q000032:analysis*; D013997:Time Factors
D010713:Phosphatidylcholines; D013109:Sphingomyelins