(440) Association between cesarean delivery and childhood respiratory outcomes

Secondary analysis of a prospective, follow-up study of children delivered in the NICHD Antenatal Late Preterm Steroids study. Children were included if their mothers were enrolled in the follow-up study and had data available for the primary outcome at age 6 or greater. The primary exposure was CD. The primary outcome was a composite of adverse childhood respiratory outcomes: abnormal pulmonary function testing, diagnosis of asthma or of other chronic respiratory illnesses, or inpatient admission for respiratory illness. It was planned a priori to assess whether results differed according to whether CD occurred after labor or rupture of membranes (ROM). Log-binomial regression was used to calculate unadjusted and adjusted relative risk (RR), with vaginal delivery as the referent group.

Results:

Of 1,218 children enrolled in the follow-up study, 833 (68.4%) delivered vaginally and 385 (31.6%) by cesarean. Children born by CD had lower birth weight, were more likely to be small for gestational age, have had respiratory distress syndrome and to have been admitted to the neonatal intensive care unit, and were less likely to have been breastfed. Mothers of children born by CD were older and more likely to have private insurance. The average age at follow up was 7 years in both groups. There was no difference in the primary outcome between children born vaginally and those born by CD (48.6% vs. 41.5%; aRR 1.14; 95% CI: 0.99, 1.31), although those born by CD were more likely to have had pneumonia (11.2% vs. 7.6%; aRR 1.48; 95% CI: 1.01-2.15) or wheezing or whistling in the chest (49.4% vs. 40.2%; aRR 1.17; 95% CI: 1.02-1.34). There was no evidence that the elevated risk was specific to CD after labor or ROM (Table 1). 

Conclusion:

Delivery via CD in children who were at risk for late preterm delivery was not associated with the primary outcome, although some individual adverse respiratory outcomes were more likely among those with CD.