>very many people are harmed by side-effects from expensive meds that are no more efficient (sometimes less so) than existing meds

That one is easy: don't fast track drugs that are only marginally better than their peers, if at all, because by definition they aren't as important.

I don't have as clear an answer for pregnancy, other than exempting pregnant users from the fast track approval, but I'm not sure how a slower process actually protects pregnancies in the first place.