This is not a Catholic symbol only:
Rev. 12:1-6 (1) A great and wondrous sign appeared in heaven: a woman clothed with the sun, with the moon under her feet and a crown of 12 stars on her head. (2) She was pregnant and cried out in pain as she was about to give birth.
I thought protestants would also accept the scriptures. Or do they only accept what they like?
You hit the nail on the head!