Use of Antibiotics During Pregnancy Increases the Risk of Asthma in Early Childhood

Abstract

To investigate whether maternal use of antibiotics during pregnancy influences the development of asthma and eczema early in life.The Copenhagen Prospective Study on Asthma in Childhood (COPSAC), a birth cohort of 411 infants born between 1998 and 2001 to mothers with a history of asthma. The COPSAC data were supplemented by data from the Danish National Birth Cohort (DNBC) consisting of 101 042 pregnant women and their children recruited between 1997 and 2003. Both cohorts were followed prospectively for 5 years.History of maternal exposure to antibiotics in the third trimester was obtained during the first COPSAC enrollment visit. Asthma exacerbations were defined as need for oral prednisolone, high-dose inhaled corticosteroids (ICS), or asthma hospitalization. In the DNBC data, investigators defined maternal antibiotic use as at least 1 filled antibiotic prescription during pregnancy. Asthma was defined as either an asthma hospitalization or an ICS prescription filled at least once.In the COPSAC birth cohort, children of mothers who used antibiotics during the third trimester were at a significantly increased risk of developing early asthma exacerbation (hazard ratio [HR]: 1.98). Maternal use of antibiotics in the third trimester did not influence the child’s risk of eczema. An increased risk of asthma after maternal antibiotic exposure was confirmed via DNBC analysis: children of mothers exposed to antibiotics during pregnancy were at a higher risk of asthma hospitalization (HR: 1.17) and ICS use (HR: 1.18). For each additional antibiotic prescription filled during pregnancy, a progressively increased risk of asthma was demonstrated (adjusted P = .01).An increased risk of asthma was found in a prospectively followed cohort of children whose mothers received antibiotics during the third trimester of pregnancy. This finding was confirmed in an unselected national birth cohort of mothers. No increased risk of eczema was detected in either cohort.Perturbing the native microbiome in the lungs has been increasingly shown to affect both asthma development and clinical control. This study adds to the mounting evidence suggesting that changing the balance between beneficial and pathogenic bacteria may play a role in the development of asthma. In a prospective analysis, these investigators implicate in utero exposure to maternal antibiotics as a significant risk factor in early asthma pathogenesis.