Relationship between Maternal and First Year of Life Dispensations of Antibiotics and Antiasthmatics.

Antibiotics are the most frequent prescription drugs used by pregnant women. Our objective was to investigate if the dispensation of antibiotics and antiasthmatics in children less than 1 year of age is associated with prenatal antibiotic exposure. A secondary aim was to explore the incidence of dispensed antibiotics in pregnancy and dispensed antibiotics and antiasthmatics in children. We conducted an observational study using the Peer Academic Detailing study database to select patients eligible for match in the Medical Birth Registry of Norway, a total of 7747 mother-and-child pairs. Details on antibiotic and antiasthmatic pharmacy dispensations were obtained from the Norwegian Prescription Database. One quarter (1948 of 7747) of the mothers in the study had been dispensed antibiotics during pregnancy. In their first year of life, 17% (1289) of the children had had an antibiotic dispensation, 23% (1747) an antiasthmatic dispensation, and 8% (619) of the children had had both. We found a significant association between dispensed antibiotics in pregnancy and dispensed antibiotics to the child during their first year of life; OR = 1.16 (95% CI: 1.002⁻1.351). The association was stronger when the mothers were dispensed antibiotics at all, independent of the pregnancy period; OR = 1.60 (95% CI: 1.32⁻1.94). We conclude that the probability for dispensation of antibiotics was increased in children when mothers were dispensed antibiotics, independent of pregnancy. Diagnostic challenges in the very young and parental doctor-seeking behavior may, at least in part, contribute to the association between dispensations in mothers and children below the age of one year.