Omg I feel you! I was told to stop duphaston at end of T1, and I feel so uncomfortable since I have history of 1 loss and I ate duphaston since week 4. 3 different gynae said I can stop duphaston at end of T1. As for prenavit, I was prescribe by 1 gynae at week 9. I stop when I change gynae at week 10 and she ask me to only take folic and duphaston till end of T1. From T2 onwards, I was prescribe Neogobion (multi bit iron supplement with folic of 1mg), fish oil and also calcium tablets . If you are really concern, check back with ur gynae on the multi vitamin. And I also will fly to see gynae if I see any spotting / weird discharge after I stop duphaston. We’ll be ok mummy!
Trust in ur dr's advice. He wont wan to harm u intentionally. Dont be too stress as it will affect the baby inside. Stay happy and healthy, thats the best u can do for ur little one.