WEDNESDAY, Dec. 12, 2007 (HealthDay News) -- Infants delivered by elective Caesarean section are up to four times more likely to have breathing problems than babies born vaginally or by emergency C-section, says a Danish study published in the Dec. 12 online issue of the British Medical Journal.
Researchers analyzed data on 34,000 births and found the 2,687 infants delivered by elective Caesarean section had a nearly fourfold increased risk of breathing problems if they were delivered at 37 weeks' gestation, a threefold increased risk at 38 weeks' gestation, and twice the risk at 39 weeks' gestation.
For example, 2.8 percent of infants delivered by intended vaginal delivery (which includes both vaginal delivery and emergency Caesarean) at 37 weeks gestation had general respiratory problems, compared with 10 percent of infants delivered by elective Caesarean section.
At 38 weeks, the rates were 1.7 percent versus 5.1 percent, and at 39 weeks, 1.1 percent versus 2.1 percent.
The reasons why elective Caesarean increases the risk of respiratory problems aren't clear. The study authors suggested that certain hormonal and physiological changes associated with labor are necessary for an infant's lungs to mature. These changes may not occur in infants delivered by elective Caesarean section.
Postponing elective Caesarean section until 39 weeks gestation may greatly reduce the risk of breathing problems in infants, the researchers noted.
The Nemours Foundation has more about Caesarean section.