Antenatal steroid therapy for fetal lung maturation: Is there an association with childhood asthma?

Over the past decade the prevalence of asthma in Canadian children has risen from approximately 7 percent to 12 percent. The specific causes of this increase in asthma are unclear. Mothers with threatened preterm labour before 34 weeks gestation in Canada are routinely offered steroids to prevent complications such as Infant Respiratory Distress Syndrome. The objective of this study is to examine the association between exposure to steroids amongst mothers and their infants and the risk of developing asthma. Mothers who reside in Nova Scotia and gave birth between January 1, 1989 and December 31, 1997 will be followed for 72 months. The incidence of childhood asthma will be compared among those infants exposed to steroids during the gestational period and those infants who were not exposed. By better understanding the fundamental relationship between health risks in the unborn infant and childhood asthma, future research, health policy and physician practice guidelines could be shaped to decrease the health burden associated with asthma.