How did she get here? Why my door and not another one? You can call 911 and ask someone to come out and help.
Something similar has happened in my area. A woman will knock on people's doors and NEEDS money, but no baby. I don't remember her reason, but the consensus is that she is looking for money for drugs. That is one part, the other is that it happens in the middle of the night, such as 2:00 in the morning. It was in a group discussion and people were asking what they should do. My response was that it is not safe to answer your door in the middle of the night. If it is someone you know, they will have called. One person in particular thought I was a terrible person, what if it was an emergency? I asked her for her address and we could send them to her. No response.
Honestly, I would not answer the door in the middle of the night, between the hours or 10 p.m. and 6 a.m. I actually have a note on my front door that says if I am not expecting you, I will not be answering the door. If someone was knocking on my door in a desperate manner, I might call 911. Since I have put the note on the door, no one knocks any more, unless I know they are coming over.