For anyone who speaks German I have written a post about my experience of cycling (road bike) during my two pregnancies, including some hacks on how to enjoy riding throughout those quite intensive nine months. I included some data on the heart rate zones, I target as well as the progress of my performance indicators during all three trimesters.

There was scarcely any resources on the subject on the internet, so I hope this might be useful to other people in the future.

Rennrad Training in der Schwangerschaft