The effect of pregnancy on asthma varies. Worsening of the disease is slightly more common than improvement, but most pregnant women do not have severe asthma attacks. The effect of asthma on pregnancy also varies, but risk of preterm delivery and poor fetal growth is increased.
Because asthma can change during pregnancy, doctors may ask women with asthma to use a peak flow meter to monitor their breathing more often. Pregnant women with asthma should see their doctor regularly so that treatment can be adjusted as needed. Maintaining good control of asthma is important. Inadequate treatment can result in serious problems.
Inhaled bronchodilators (such as albuterol) and inhaled corticosteroids (such as beclomethasone) can be taken during pregnancy. When inhaled, the drugs affect mainly the lungs and affect the whole body and the fetus less than when they are taken by mouth. Aminophylline (taken by mouth or given intravenously) and theophylline (taken by mouth) are not usually used during pregnancy. Corticosteroids taken by mouth are used only when other treatments are ineffective or after asthma suddenly worsens.
Being vaccinated against the influenza (flu) virus during the flu season is particularly important for pregnant women with asthma.
Last full review/revision December 2008 by Sean C. Blackwell, MD