I am pregnant with asthma, although its not chronic asthma I'm guessing the rules still apply. You need to have your asthma in a "controlled" state. Which means that if you are requiring an inhaler more than twice a day, you should really be taking preventative medicine/inhalers.
I noticed that my asthma got worse in my first trimester but after that, it resumed to normal levels. What I would suggest is that you contact your doctor and develop an asthma care plan to ensure your asthma is under control. The last thing you want is to be breathless and scared for your baby's health.
Bye for now...