A Meta-Analysis of Adverse Perinatal Outcomes in Women With Asthma

Abstract

Asthma is a relatively common chronic medical condition among pregnant women. Although some studies have suggested that maternal asthma increases the risk of perinatal complications in both mothers and infants, the published data are conflicting. Thus, the aim of this meta-analysis was to investigate whether maternal asthma is associated with an increased risk of adverse perinatal outcomes and to determine the extent of these effects. Electronic databases were used to identify abstracts of studies published between 1975 and 2009 using the following search terms: (asthma or wheeze) and (pregnant or perinatal or obstetrics). All observational studies were either prospective or retrospective in design and reported at least 1 perinatal outcome of interest. Among women with and without asthma, the relative risk (RR) was compared for at least 1 perinatal outcome, and, when possible, stratified by active asthma management and no active asthma management. Of the 103 articles identified for possible inclusion, 40 involving a total of 1,637,180 women met the inclusion criteria, including data on birth weight, preterm labor, preterm birth, and preeclampsia. Several adverse perinatal outcomes were associated with maternal asthma: an increased risk of low birth weight (RR, 1.46; 95% confidence interval [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 preeclampsia (RR, 1.54; 95% CI, 1.32–1.81); all P values were <0.0001 or <0.00001. However, with active management, the risk of preterm delivery and preterm labor was reduced to clinically and statistically nonsignificant levels (RR, 1.07; 95% CI, 0.91–1.26, and RR, 0.96; 95% CI, 0.73–1.26, respectively). These findings indicate that maternal asthma increases the risk in both infants and mothers of several perinatal complications, including those affecting the baby's size and timing of birth and preeclampsia. The data suggest that active asthma management to reduce the exacerbation rate has the potential to decrease the risk of perinatal complications.