Can we switch from one BC pill to another straightaway or do we have to wait for menses then start new BC pill??

Yes. You do not need to finish the pill pack before switching to another method. You can stop taking your pill at any point in the pack. If you are switching to pills from another method, you should start by taking the first pill in the pack. These rules also apply to switching from one kind of pill to another kind of pill. You may have changes in your period after switching birth control methods. Thi.