A meta-analysis of adverse perinatal outcomes in women with asthma

Background Asthma is a common condition during pregnancy and may be associated with adverse perinatal outcomes. Objective This meta-analysis sought to establish if maternal asthma is associated with an increased risk of adverse perinatal outcomes, and to determine the size of these effects. Search strategy Electronic databases were searched for the following terms: (asthma or wheeze) and (pregnan* or perinat* or obstet*). Selection criteria Cohort studies published between 1975 and March 2009 were considered for inclusion. Studies were included if they reported at least one perinatal outcome in pregnant women with and without asthma. Data collection and analysis A total of 103 articles were identified, and of these 40 publications involving 1 637 180 subjects were included. Meta-analysis was conducted with subgroup analyses by study design and active asthma management. Main results Maternal asthma was associated with an increased risk of low birthweight (RR 1.46, 95% CI 1.22-1.75), small for gestational age (RR 1.22, 95% CI 1.14-1.31), preterm delivery (RR 1.41, 95% CI 1.22-1.61) and pre-eclampsia (RR 1.54, 95% CI 1.32-1.81). The relative risk of preterm delivery and preterm labour were reduced to non-significant levels by active asthma management (RR 1.07, 95% CI 0.91-1.26 for preterm delivery; RR 0.96, 95% CI 0.73-1.26 for preterm labour). Author's conclusions Pregnant women with asthma are at increased risk of perinatal complications, including pre-eclampsia and outcomes that affect the baby's size and timing of birth. Active asthma management with a view to reducing the exacerbation rate may be clinically useful in reducing the risk of perinatal complications, particularly preterm delivery.