Nursery theme might cause drama?

So I wanted to make my little girls nursery rainbow themed (there’s so much cute stuff out there!) but my sister in law has had 3 miscarriages in the past year and a half and I’m afraid the rainbow theme will be offensive to her? She is a VERY sensitive person, and takes everything to heart. Do I just stay away from that theme even though I love it? Any mamas out there who have miscarried, is it offensive to you if someone who does not have a rainbow baby do a rainbow theme?