Figure 4.

Effect modification of maternal asthma status and the cumulative number of prenatal antibiotic courses on the risk of childhood asthma. Multivariable logistic regression adjusted for maternal age, education, smoking, presence of group B Streptococcus infection, delivery method, and infant characteristics including birth hospitalization length of stay, gestational age, birth weight, infant race, sex, and number of living siblings at home. The cumulative number of prenatal antibiotic courses was assessed with restricted cubic splines (4 knots). The gray band around the lines indicates the 95% confidence interval.