Rainbow Baby?

I saw in another app someone said that it’s offensive for women to say they’re having a rainbow baby after a miscarriage when they already have a healthy child.

So like for instance I have a 5 year old but I’ve had three miscarriages and am currently 13 weeks pregnant. She found it offensive if I called this baby my rainbow baby.

Thoughts?

Edit: Her reasoning was because women who already have children don’t truly know what it’s like to have a loss or don’t know what it’s like to actually have infertility.