LONDON, UNITED KINGDOM. A team of British and Finnish researchers has previously reported their finding that birth by Caesarean section is associated with a 40 per cent increase in asthma among seven-year-old children. They now report that the prevalence of asthma in 30-year-old men and women born by C- section is more than three times higher than among adults born via a normal vaginal delivery. Their study involved 1953 men and women born in 1966. At that time C-sections were used in emergencies only so only five per cent of the births involved this procedure. The study participants were interviewed and examined in 1997. The researchers discovered that while the prevalence of asthma in the normal delivery group was only 4.5 per cent it was 13.6 per cent in the C-section group corresponding to a three-fold increase in risk even after adjustment for possible confounding variables. There were no significant differences in the incidence of hay fever or eczema between the two groups. The researchers point out that the use of C-sections has skyrocketed in recent years and now accounts for as many as 25 per cent of all deliveries in some hospitals. Given the clear association between asthma and C-section delivery, this should be cause for considerable concern.
Xu, Baizhuang, et al. Caesarean section and risk of asthma and allergy in adulthood. Journal of Allergy and Clinical Immunology, Vol. 107, April 2001, pp. 732-33 (brief communication)