Has anyone had experience with their IUD falling out and becoming pregnant immediately?

My sister’s IUD fell out on 9/25 and she had some spotting (normal period for her) she she and hubby did the deed on 9/27 thinking it was safe.

Then they moved across the state and haven’t had time.

Anyway, she popped a positive pregnancy test on 10/15

She’s concerned about the health of the baby and the earliest her doc can get her in is next Friday 😕

In any case, prayers and positive vibes for her please 🙏🏼