Houseguest hasn’t left, HELP!!

I have a house get that i said could stay with us for 3 weeks, we’ll the 3 weeks would have been up yesterday as they came 11/15.... they have not said anything about leaving but i did hear them on the phone a few days ago saying to someone they needed to find somewhere to go... how do i go about telling them the 3 weeks is up when i know they know? I’m 32 weeks pregnant and don’t want any confrontation!