Neonatal Respiratory Morbidity Linked to Near-Term Cesareans


PRAGUE — Elective cesarean sections that are carried out near the end of term may be more likely to result in neonatal respiratory morbidity than planned vaginal births, Dr. Anne Kirkeby Hansen reported at the 20th European Congress of Perinatal Medicine.

Using data from the prospective Århus Birth Cohort, Dr. Hansen and her colleagues identified 2,438 singleton neonates born in 1998–2005 by elective cesarean section at a gestational age of greater than 36 weeks.

Overall, 403 (17%) of these infants had respiratory morbidity classified as respiratory distress syndrome, transient tachypnea of the newborn, or persistent pulmonary hypertension of the newborn, said Dr. Hansen of the Perinatal Epidemiology Research Unit at Århus (Denmark) University Hospital.

Respiratory morbidity occurred significantly more often among infants who were delivered by elective C-section at 37 weeks (4.5%) or 38 weeks (3.4%) than among those who were born via an intended vaginal delivery (1.4% and 1%, respectively). The relative risk of respiratory morbidity was 3.2 and 3.6 times higher if an elective C-section was performed at those gestational ages instead of an intended vaginal delivery, which included deliveries by vacuum, forceps, and emergency C-section.

Elective C-section at 37 weeks was associated with a significant, nearly sixfold higher relative risk of respiratory morbidity than among infants born by intended vaginal delivery at a gestational age of 40 weeks, 0.8% of whom had respiratory morbidity. The relative risk of respiratory morbidity for those born by C-section at 38 weeks was 4.4 times higher than that of neonates who were intended to be born vaginally.

Infants born by elective C-section at 37 weeks were 3.6 times more likely and those born at 38 weeks were 2.7 times more likely to have respiratory morbidity than infants born by elective C-section at 39 weeks.

The incidence of respiratory morbidity did not differ significantly between neonates in either category at a gestational age of 39 or 40 weeks.

“Both way of delivery and timing of elective cesarean section influence the risk of respiratory morbidity,” Dr. Hansen said.

“These results indicate that elective cesarean section is associated with an increased risk of respiratory morbidity regardless of gestational age. Timing of elective C-section is crucial as the risk of respiratory morbidity increases with decreasing gestational age,” she said.

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