I'm sorry: that's really hard. :(
FWIW, I considered myself pretty darn educated about pregnancy and childbirth last time, but I didn't even THINK about doppler use as a potential issue - even though I tried to avoid unnecessary ultrasounds. This time I'm avoiding the doppler, simply because it seems kind of inconsistent to do one but not the other (although I do plan to have the 20-week anatomy scan). Interestingly, my midwife said the fetoscope probably wouldn't work until 26 weeks or so, so I was expecting to see the baby before I heard it! I'm pleased to hear it can be used earlier than that, though. Anyway - my point is, there is SO much to know about pregnancy, birth and the like. There will ALWAYS be something we find out after the fact - "Ooh, I wasn't supposed to eat that?" or "I was meant to supplement with that?", or "[routine intervention] is linked to [rare complication]?"... or we can know all about the major "conditions" like gestational diabetes and placenta previa, and then get caught completely by surprise by some off-the-wall condition that one in a million women gets. You know? It doesn't mean that we are ignorant, neglectful mothers - it means we're people.
Also, I wish midwives would be clearer about the doppler thing. Neither of mine told me that it used ultrasound waves. You'd think, being midwives, that they'd get enough crunchy/low intervention-type clients who might want to decline them if they knew about it. It doesn't seem to be common knowledge, so I think they should just say before using it the first time, "This uses ultrasound waves", explain how equivalent it is to an ultrasound, and give people the choice. You know?