Babies born by caesarean have a 50 percent increased risk of developing asthma and for emergency c-sections, the risk is even higher, say researchers at the Norwegian Institute of Public Health. Researcher Mette Christophersen Tollånes explained that there were two main theories about why caesarean sections could cause asthma. The first is that babies who are born by caesarean section are not exposed to their mothers' bacteria during birth, which is detrimental for development of the immune system.
The other is that babies born by caesarean section have more breathing problems after birth because they are less exposed to stress hormones and compression of the chest, since these mechanisms contribute to emptying the lungs of amniotic fluid. Tollånes speculates that this may negatively affect lung function in the long term.
Why emergency caesarean sections had a stronger effect on the risk of asthma than planned caesarean sections cannot easily be explained by any of these theories, says Tollånes.
The new findings were based on an analysis of over 1.7 million births reported to the Medical Birth Registry at the Norwegian Institute of Public Health in the period 1967-1998. Multiple births and children with congenital malformations were excluded. The children were monitored until they became 18 years old.
Related:
Environmental Toxins Behind Asthma?
Researchers Link Asthma To Birth Order
Hormones Linked To Lung Function And Asthma
Source: Norwegian Institute of Public Health
