Antibiotic exposure in third trimester linked to asthma in offspring: BMJ

Denmark: In utero exposure to antibiotics in mid-to-late pregnancy increases asthma risk in vaginally born children, finds a recent study in the BMJ journal Archives of Disease in Childhood. According to the study, delivery mode may modify this association. No association was found for antibiotic exposure in the first trimester of pregnancy. 

The use of antibiotics during pregnancy is suggested to increase asthma risk in offspring but findings are not consistent. Previous studies differed significantly in sample size, research design, diagnostic methods, follow-up period, and timing of exposure in pregnancy.

Cecilie Skaarup Uldbjerg, Aarhus University, Aarhus, Denmark, and colleagues aimed to investigate if antibiotic exposure during pregnancy is associated with childhood asthma and if this relationship was conditional on mode of delivery and timing of exposure.

The researchers recruited participants from the Danish National Birth Cohort (DNBC), conducted in 1996 to explore the impact on health of prenatal and early life exposures. The mums-to-be were referred to the DNBC by their family doctor at their first antenatal visit at 6-10 weeks of pregnancy between 1996 and 2002. Of the 96,832 children born to these women, 32,651 were included in this study.