Impact of Delivery Mode on Childhood Asthma and ADAM33 Methylation: A Birth Cohort Study

Abstract

Cesarean section (CS) rates and childhood asthma are rising, but the link is unclear. In this nested cohort (N=240), elective CS was associated with neonatal ADAM33 hypomethylation (median 20% vs. 100% in emergency CS, p<0.001). While methylation normalized by preschool age, lower levels correlated with higher asthma risk. These findings reveal a novel epigenetic mechanism linking delivery mode to respiratory health, suggesting early-life programming of asthma susceptibility.