Low-dose Corticosteroids Safe for Asthma in Pregnancy; High Doses, May Affect Outcomes

While long-acting beta2-agonists (LABAs) and low to moderate doses of inhaled corticosteroids for asthma in pregnancy were not associated with an increased prevalence of adverse perinatal outcomes in a recent cohort study, there was a slight trend toward increased prevalence of low birthweight, premature birth, and small for gestational age infants when mothers were exposed to inhaled corticosteroids at high doses.¹
   
During pregnancy, asthma symptoms can improve, worsen, or remain unchanged.² Asthma symptoms typically worsen in women who have severe asthma and improve or are unchanged in women with mild asthma. Well-controlled asthma poses no significant maternal or fetal risk. Uncontrolled asthma, however, can cause serious maternal and fetal complications. Maternal complications include hypertension, toxemia, premature delivery, and even death (rarely). Fetal complications include an increased risk of stillbirth, intrauterine growth restriction, premature birth, low birthweight, and a low APGAR score at birth.
   
There are no asthma controller medications that have been proven entirely safe to use during pregnancy, and the benefits of the medication should always be weighed against the risks. Currently, safety data on the use of LABAs and inhaled corticosteroids in pregnancy are lacking, but women with more severe disease often are prescribed these agents or continue their use during pregnancy. To assess whether the use of LABAs and inhaled corticosteroids during pregnancy are associated with an increased prevalence of low birthweight, preterm birth, and small for gestational age, researchers identified a cohort of women with asthma who gave birth between 1998 and 2008 and analyzed the prevalence of adverse perinatal outcomes.
   
A total of 7376 pregnancies were included in the analysis, which found that 56.9% of pregnancies had exposure to inhaled corticosteroids and 8.8% had exposure to LABAs. All women who used LABAs during pregnancy also used inhaled corticosteroids. Overall, the prevalence was 7.7% for low birthweight, 9.5% for premature birth, and 13.5% for small for gestational age. In the LABA group, there was no increased prevalence for any of the 3 adverse perinatal outcomes. However, there was an insignificant trend toward increased prevalence of low birthweight, premature birth, and small for gestational age when the mean dosage of inhaled corticosteroid exceeded 125 micrograms/d.
   
These findings suggest that more research is needed to determine whether higher doses of inhaled corticosteroids are associated with adverse perinatal outcomes. Overall, however, the use of LABAs and low to moderate doses of inhaled corticosteroids during pregnancy does not increase the risk of low birthweight, premature birth, or small for gestational age.

Pertinent Points:
- The use of long-acting beta2-agonists was not associated with an increased prevalence of low birthweight, premature birth, or small for gestational age.
- Higher doses of inhaled corticosteroids may trend toward an increased prevalence of low birthweight, premature birth, or small for gestational age.
 

References:

1. Cossette B, Forget A, Beauchesne MF, et al. Impact of maternal use of asthma-controller therapy on perinatal outcomes. Thorax. April 13, 2013. doi: 10.1136/thoraxjnl-2012-203122. [Epub ahead of print]
2. American College of Allergy, Asthma, & Immunology. When pregnancy is complicated by allergies and asthma. Available at: http://www.acaai.org/allergist/liv_man/pregnancy/Pages/default.aspx. Accessed July 5, 2013.