Project 173037

The prevalence of asthma among pregnant women is between 4 to 7% and is known as one of the most frequent chronic diseases encountered during pregnancy. Concerns about teratogenicity of asthma medications during pregnancy might lead women to stop or reduce their use of controller therapy, but this fear must be balanced against the risk of loss of asthma control and exacerbations. Lack of oxygen to the foetus can lead to perinatal mortality, intrauterine growth retardation, and preterm birth. Inhaled corticosteroids is the controller therapy of choice during pregnancy and its discontinuation may be one of the most important reasons leading to uncontrolled asthma during pregnancy. Evidence on the association between asthma control through the use of controller therapies during pregnancy and the prevention of adverse perinatal outcomes is scarce. We plan to reconstruct a large cohort of pregnancies from asthmatic women from the linkage of three databases: Régie de l'assurance-maladie (RAMQ) database which provides medical service and prescription claims data, MED-ECHO database which provides hospitalization data and the birth and death registries. This cohort of pregnancies will be used to investigate whether or not there is an association between the dose of inhaled corticosteroids used during pregnancy and the risk of small for gestational age babies, low birth weight babies and preterm delivery. The use of inhaled corticosteroids during pregnancy will be measured with medication claims data recorded in the RAMQ databases. This study will allow us to evaluate whether or not inhaled corticosteroids taken at moderate to high doses during pregnancy are safe for the fetus.