Many women with asthma are concerned about the effect of drugs on the fetus, and this can lead to inappropriate cessation of treatment in early pregnancy. However, it is safer to take asthma drugs in pregnancy than to leave asthma uncontrolled. Inhaled beta-sympathomimetics are safe, as is theophylline, although its metabolism is altered and drug levels need to be monitored. Long-acting B2 agonists like salmetrerol do not cause fetal malformation or FGR in prospective studies and there is limited systemic absorption. Inhaled corticosteroids prevent asthma exacerbations in pregnancy and have been shown to be safe with no association with fetal malformations or perinatal morbidity in large studies and reviews. Oral corticosteroid use in the first trimester has been associated with an increased risk of fetal cleft lip or palate in epidemiological studies, but the increase i risk is small and not confirmed in other work. Data are scarce on the safety of the relatively newer leukotriene antagonists, although no adverse outcomes have been reported.