See below. Most of the inhalers used for asthma are safe in pregnancy. But make sure that you consult a doctor, as it is particularly important for your baby that your asthma be controlled.
Safe Medications. Its very important to manage asthma as aggressively as possible during pregnancy as you are dealing with two patients now. You and and your baby. Generally pregancy category b drugs are used, which means that the drug is safe in animal studies, but no human studies have been done. (nobody wants to do studies on pregnant females!) its very important to maintain good control of asthma now.
Multiple factors. You want to avoid or minimize exposure to things that make your asthma worse. You should let your doctor know you are pregnant and review your medications. You should take your medications as prescribed by your doctor. You should have a peak flow meter at home and keep track of your numbers periodically. You should get the flu shot. You should do whatever amount of exercise you are allowed to.