It all sounds a bit scary doesn't it? I guess no intervention is the best, but only you can know and decide what you will need/want/be comfortable with.
Read reliable sources and definitely give your GP the 3rd degree about the effects and risks of each drug. I think each has its pros and cons, and you will just need to decide what is important to you, and what will make you comfortable with the idea of birth.

All the best, and you're totally right, you do still have a fair bit of time to decide what options you would consider