The Influence of Timing of Elective Cesarean Section on Risk of Neonatal Pneumothorax

Abstract

Some earlier reports identified neonatal pneumothorax in as many as a third of infants with iatrogenic respiratory distress syndrome. More recently, pneumothorax and/or severe, persistent pulmonary hypertension have been observed in infants delivered by elective cesarean section. These studies, however, were limited to infants admitted to intensive care. The lethality of iatrogenic pneumothorax necessitates prompt diagnosis and specialized care. This study enrolled 66,961 term infants born during a 2-year study period in an attempt to learn whether the timing of elective cesarean delivery influences the risk of neonatal pneumothorax. Just over one-fourth of infants were delivered by cesarean section: electively in 56% of instances and by emergency section in 44%. In 5408 instances, elective cesarean section was carried out before 39 completed weeks of gestation. Pneumothorax was diagnosed in 59 newborn infants, representing 0.8 per 1000 births. All of them were managed by thoracostomy. The incidence of pneumothorax was increased at 2.9 per 1000 births in those infants who were delivered by elective cesarean section, compared with both infants delivered by emergency section and those delivered vaginally. The odds ratio (OR) for pneumothorax following elective cesarean delivery, compared to emergency cesarean delivery, was 4.21 (95% confidence interval [CI], 2.04-8.74), and compared to vaginal delivery, 7.95 (95% CI, 4.41-14.32). In elective cesarean deliveries, the incidence of pneumothorax declined progressively and significantly from the 37th gestational week onward. There was a similar but less significant trend for vaginal delivery but not for emergency cesarean delivery. None of the infants with pneumothorax died, but 14% of those born by elective cesarean section developed pulmonary hypertension, necessitating high-frequency oscillatory ventilation and nitric oxide inhalation. Elective cesarean delivery at term carries an increased risk of neonatal pneumothorax compared to either emergency section or vaginal delivery. Performing elective cesarean deliveries after 39 completed weeks of gestation would be expected to lower the risk of iatrogenic neonatal pneumothorax.