Hello!
Studies report that some mothers experience an improvement in their condition during pregnancy, while others experience the opposite. In any case, it would be wise to avoid or reduce your exposure to certain environments or conditions that could increase your symptoms (e.g. dust, certain animals, etc).
Please note that poorly controlled asthma in a pregnant woman can affect not only her but also the fetus. Ventolin and Flovent should therefore be continued without any problems in order to maintain good control of your condition.
As for Avamys, there is not a lot of data on its safety, but the drug itself is very poorly absorbed when used properly. If your nasal congestion is severe, you may want to use it, if possible for a short period of time. Reactin is considered safe during pregnancy, so it can be continued if necessary.
Finally, montelukast is not recommended as a first line treatment, but it could be reserved for patients who have less control of their symptoms. I would ask you to speak to your pharmacist who is more familiar with your case, so he/she can guide you more precisely, review the use of your pumps and inhalers if necessary, and finally review your complete medication profile with you.