Has anyone had experience with hiking trails and adventurous type vacations while pregnant?

We are going to Iceland next week, I'll be 10 weeks. I've never been there but DH is planning an active vacation with a lot of outdoor activities. I am planning on just going along and taking a lot of rest breaks when I need to and staying hydrated, but wanted to know if anyone had done this type of travel and have any advice.

Thanks in advance!