Hi yes I was also on duphaston and also cyclogest insert during first trimester due to bleeding. The backache is likely due to baby growing, I find that some daily light stretches helped me ease any backaches. Take care!
I was prescribed this when i had brown discharge. In early weeks. Took it about 2 or 3 weeks then was ok. But my lower back pain started later. With pregnancy pillow it helped me to sleep better on the side.