Congratulations on all your 'normals' its really lovely to hear but Im sure much lovlier to say!
Given that your doppler was normal and your previous history, I would suggest that another doppler in 4 weeks time would be appropriate especially if there are beginnings of other PE signs.
There really is not much point doing a doppler as the pregnancy progesses largely due to the fact the arteries become harder to see and therefore can be difficult to interpret.
The good news though is that if the doppler is good now I would not expect to see a deterioration in a few weeks time, hence my thoughts of any PE symptoms brewing.
I hope this helps and long may all your 'normals' continue!
Every Woman is entitled to understand what happened in her pregnancy when pre eclampsia strikes. I hope to be able to support that process.