Intrauterine bacterial growth at birth and risk of asthma and allergic sensitization among offspring at the age of 15 to 17 years

Background: Microbial colonization of the airways and intestine during birth might have an effect on the risk of asthma and allergic diseases later in life. Objective: We sought to evaluate the association between intrauterine microbial growth at the time of delivery and the development of asthma and allergic sensitization among offspring. Methods: Intrauterine bacterial culture results were recorded at the time of cesarean delivery of 460 children who were born at Kuopio University Hospital during 1990-1992. When the children reached the age of 15 to 17 years, self-administered questionnaires were sent to the mothers, and 382 of the children were also examined by using skin prick tests. Results: Intrauterine growth of potential pathogenic anaerobic bacteria and Streptococcus species at birth was associated with an increased risk of doctor-diagnosed asthma ever (odds ratio [OR], 4.51 [95% CI, 1.56-13.01]; OR, 2.53 [95% CI, 1.19-5.38]) and doctor-diagnosed current asthma (OR, 7.34 [95% CI, 2.44-22.03]; OR, 3.37 [95% CI, 1.46-7.76]) at the age of 15 to 17 years compared with the risk seen in subjects with negative microbial cultures. These findings remained significant also after applying the Bonferroni correction. No significant association after the Bonferroni correction was detected between intrauterine microbial growth and allergic sensitization among offspring. Conclusion: The results of this study indicated that specific intrauterine microbial growth at the time of birth might increase the risk of asthma among offspring through inflammatory mechanisms. These results indicate new potential targets for future studies on the effects of maternal vaginal microflora and intrauterine infection in the development of asthma among children (J Allergy Clin Immunol 2009;123:1305-11.)