Mode of Delivery and Asthma at School Age in 9 European Birth Cohorts

Abstract

Evidence on the association between mode of delivery and asthma at school age is inconclusive. We assessed the associations between specific modes of delivery and asthma in children from 9 European birth cohorts that enrolled participants between 1996 and 2006. Cohort-specific crude and adjusted risk ratios for asthma at ages 5-9 years were calculated using Poisson regression models and pooled. A sensitivity analysis was carried out in children born at term to reduce confounding due to perinatal factors. The study included 67,613 participants. Cohort-specific rates of cesarean delivery varied from 9.4% to 37.5%. Cesarean delivery, as opposed to vaginal delivery, was associated with an increased risk of asthma (adjusted risk ratio (aRR) = 1.22, 95% confidence interval (CI): 1.02, 1.46). Compared with spontaneous vaginal delivery, the adjusted risk ratio was 1.33 (95% CI: 1.02, 1.75) for elective cesarean delivery, 1.07 (95% CI: 0.94, 1.22) for emergency cesarean delivery, and 0.97 (95% CI: 0.84, 1.12) for operative vaginal delivery. In children born at term, the associations were strengthened only for elective cesarean delivery (aRR = 1.49, 95% CI: 1.13, 1.97). The large sample size allowed analysis of the associations between specific modes of delivery and asthma at school age. The increased risk of asthma associated with elective cesarean delivery, especially among children born at term, is relevant in counteracting the increasing use of this procedure, which is often performed without a clear medical indication.

Low birth weight contributed to increased serum IL-6 levels in infantile respiratory syncytial virus infection

“…Additionally, a previous study by Rusconi et al showed that the adjusted risk ratio for development of asthma was 1.33 for elective cesarean delivery compared with spontaneous vaginal delivery [ 24 ]. However, Werner et al found no support for the hypothesis that children delivered by caesarean section have an increased risk of asthma during the first 15–18 years of life [ 25 ].…”

The developing gut microbiota and its consequences for health

“…It is then associated with both maternal and fetal stress and exposition to vaginal microbiota, favoring a colonization more similar to vaginal delivery. If Huang et al 49 found a 20% increase in the subsequent risk of asthma in children delivered by both elective or emergency cesarean section, Rusconi et al 54 who worked on individual data from nine European birth cohorts concluded that the increased risk of asthma is more associated to elective cesarean delivery, especially among children born at term. Prematurity and breastfeeding are both perinatal determinants that impact the bacterial establishment and they are studied for their role toward allergy risk.…”

Microbiome and asthma

“…The mode of delivery has a significant influence on colonization. Babies delivered via caesarean section typically have more Staphylococcus species, Bacillales, Propionobacterineae, Corynebacterineae, Firmicutes and Acinetobacter species with fewer Actinobacteria and Bacteroidetes, while vaginal delivery has been linked to increased colonization with Clostridia [ 38 , 47 ]. Clostridia metabolize fibers to SCFAs, which can have systemic anti-inflammatory effects as described above.…”