Beta Stimulants in Pregnancy-Any Harm?

Recent review in AJOG points to possible association between beta stimulants used for tocolysis (>2 weeks) as well as oral beta stimulants used in asthma with possible autism and other psychiatric disorders. They caution to limit the terbutaline to a max of 48 hours and use only inhaled albuterol. They discuss shift of balance between sympathetic and parasympathetic activity due to over stimulation of beta2 receptors during nervous system formation. Interesting buy, I feel it needs more evidence and research.