We read with concern the recent review of in utero exposure to beta 2 agonists and possible associations with adverse behavioral outcomes. The suggestion that beta 2 agonists used in therapeutic doses for treatment of maternal asthma during pregnancy may be responsible for an increased rate of autism in children of these mothers is a very serious one. If true, it would suggest the need for a paradigm shift in the treatment of asthma during pregnancy.

We wish to highlight the paucity of evidence on which these claims have been made. The claim of terbutaline being associated with delayed development of expressive language was based on a single case report, which on reading of the original text was in fact thought likely to be a constitutional delay with no pathologic process. The reference to correlation of autism with aerosol use for asthma is not from a recognized peer-reviewed journal, and the aerosol use was by a single asthmatic mother with 3 autistic sons. The claim that “a reported association of maternal asthma and autism spectrum disorders in the offspring might be explained by treatment with beta 2 adrenergic agonists for treatment of asthma during pregnancy” is contrary to the findings of the article cited, whose authors specifically state that “no independent effect was observed for medication use.” Finally, a personal communication is cited of work that we presume has yet to be subject to a peer-review process that may show a “modest” increase in the risk of autism spectrum disorder (ASD) in offspring of mothers taking beta 2 agonists during the first and second trimesters.

If a true cause-and-effect relationship of inhaled beta agonist use for treatment of maternal asthma during pregnancy and ASD exists, this is of course vital to know. However, we would strongly suggest that, regarding inhaled beta agonist use at least, the references supplied to support such sweeping statements as “beta 2 agonists should only be used when alternate drugs are ineffective or unavailable” are both grossly inadequate and in at least 1 case a misinterpretation of the originally published data. At present, the evidence does not support a change in the current recommendations for management of asthma with beta 2 agonists. Undertreatment of this common and potentially lethal maternal condition is a far greater risk than the risk of autism suggested by this article.